Well There‘s Your Problem - Episode 121: Therac-25

Episode Date: January 13, 2023

too much electrons Dr. Tom Bowers on Twitter: https://twitter.com/fancywookiee Our Patreon: https://www.patreon.com/wtyppod/ Our Merch: https://www.solidaritysuperstore.com/wtypp Send us stuff! our address: Well There's Your Podcasting Company PO Box 40178 Philadelphia, PA 19106 DO NOT SEND US LETTER BOMBS thanks in advance in the commercial: Local Forecast - Elevator Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 3.0 License http://creativecommons.org/licenses/by/3.0/

Okay. Hello and welcome to Well, There's Your Problem. It's a podcast about engineering disasters with slides. I'm Justin Rosniak. I'm the person who's talking right now. My pronouns are he and him. All right, go. I am Alex Gordalkalli. I'm the person who's talking now. My pronouns are she and her. Jalium. Jalium. Here's the thing. Very formal Jalium. My pronouns are he and him. I'm Liam Anderson. And one of my friends just spelled karaoke. K-E-R-O-K-E. Caroke. Isn't that looking like a Caroke. That's the guy who pioneered assisted suicide, right? Yeah, Dr. Caroke. I just got in Texas and said, going to Caroke late? Yeah, 10 to 1030. Damn, y'all young or something. Y'all spelled wrong. Love your

friends. We have a guest. Guest, please introduce yourself. Hello. My name is Tom Bowes. My pronouns are he, him, for sake of argument. Tom, why the fuck are you here? We'll revisit this at a future time. Yeah, maybe. I've done the visiting this and we'll kind of come back around to it at some point, I'm sure. But for now, he, him, is fine. So, yes. So, we seem to have... Will you not explain why Dr. Tom is here? Oh, we do need to explain why Dr. Tom is here. Dr. Tom, why are you here? I'm here because we are going to talk about a medical disaster. Yeah, you fuckers have been asking for this forever. Yes. So, what we have on screen here, this is a, well, this is in fact a Therax 6 linear accelerator. This is very sort of

Star Trek original series. Yeah, it's the device. They're going to put you in the device. You got too sick, and now they're going to put you in a device, something which I would not enjoy. I'm like halfway between, this is the medical device, and this is what's inside the, you know, the vaporization chambers in that episode where they're having the virtual war. You guys remember the beginning of Quake 4? It's kind of like that. This is, this, this, this, this has the exciting tagline. This is a reliable, high-output linear accelerator featuring extra-large, fully-flattened treatment fields. Looks like a big sewing machine, and it looks like they just put you under it, and then I don't

know. It uses a big, big red flashlight, and it just sort of like knocks all the illness out of you. It's maybe the idea. I love that sort of, even in sort of the, you know, what, early 80s, late 70s here, we've got, we've already agreed that sort of the laser, sort of laser eyes, laser sort of, that's good for marketing, that sells a product. Also, coming in a color that just, you know, medical devices do not have this range of colors anymore. The 1970s, 1980s, sort of the end of an era for, for sort of interestingly colored devices and like contrast trim in like an olive. It's, it's wild. It's got, got some chromed bits. And now, now they all just come in beige.

Yeah, it's, it's, it's a white machine. Yeah, I think, I think they'd look less intimidating. Oh, that's more designed than white. Yeah, you could go the opposite direction, right? I think if you played it up a bit, if you, if you put me in like a black, like a jet black MRI, and you were like, yeah, this is the goth MRI. I would be a lot less scared. It has like a, has like a, like a pointed arch in front, as the entrance. Yeah, every time they put you near the radiologist is like, prepare the sacrifice and just black metal starts playing. This is, this is sort of commensurate with what I'm about to be feeling.

Got like, got like gargoyles on it and shit, you know, I love the more hammer 40 K assessing when it quenches. If it quenches the gas, it goes out of gargoyle on the outside of the building. Yeah, incredible. You guys see that scene from punch back at our dog? Yeah. As someone who has at least some of a medical sort of radiation science degree, then yeah, that's the kind of thing that, that a lot of sort of radiotherapists and

radiation scientists would be into. Yeah, getting into this, because you really want some like hooded robes, you know, yeah, like driving music or this sort of stuff. I mean, it's sort of, I have sort of, well, I do have a degree. I have, but I have a third class degree in this and research this basically involved relearning my entire sort of the x-ray part of my course, which had I done that at the time, I would have done something better. I'm the only one here who is like, I will never go back to my degree for a

subject because we've made everyone else here, except me, revisit their degree. And I'm not going back to law school for this. I'm not sure how I would, but I'm not going back to any of my own books for this. But so this thing is the precursor of what we're going to talk about, which is this is the one you can still find pictures of because it worked by popular demand. We're talking about this thing's less successful descendant, Therac 25. But first, we have to do the goddamn nose.

Come on. So we managed to have a helicopter crash in Australia and two helicopters smacked directly into each other at, I guess, like a heliport. Two sighting helicopters, one of them climbing the other one, landing. And there's actually footage from on board, the one descending, which shows the thing that you don't want, which is a passenger grabbing the pilot's arm and pointing so as to convey there is a helicopter that you are about to fly into. Whoops.

So the the helicopter is taking off shears the front off of the one landing, including the entire windscreen. Like the first sort of like, say, like half a, you know, half a foot of the helicopter was just gone. It's just missing. That still manages to land safely, which, you know, credit to that pilot who now does not have a windshield and has just had a very, very close shave from some like rotor blades or fuselage or whatever, managing to land that safely.

The other one, as we see here, has lost the entire tail. That did not make a safe landing. It makes a very deadly landing and kills everyone on board. That's gone poorly. Yeah, the last I heard that there was one, there was one survivor from the Gratial has that now changed. I believe that has now changed. I believe everyone has died.

But yeah, so these are all like tourists because this is a sightseeing helicopter and yeah, helicopters have seen the dangerous machines. I'm terrified of the moving parts looking for a place to crash. As I put on the the car on here, the only thing more dangerous than a helicopter is two helicopters. In fact, it's twice as dangerous. Bloody hell.

You remember when we did that Kobe Bryant thread and people got really mad at us? Mm hmm. Yeah, I've been on helicopter tours before. I went on one over the Grand Canyon as a child and the whole time I was like, well, if I die, at least it'll be an interesting fall. It'll be very scenic, you know? Yes, like 20 seconds of just like going into a big hole on the ground, like Joshua Graham and I'm like, yeah, this is this is fine to me. I can't imagine going on one of those tours just because it'd be so loud.

You would get to the point where it's loud enough that, you know, A, I can't hear anything and then my vision starts going blurry. You can't hear anything anyway. This is true. But when there's when there's enough noise, when there's enough noise, my other senses start going. It's actually not that it's not that bad. Like once they put the like the headset,

the like air defenders and radio thing on you, it's really not so bad. It feels feels I've been in a much louder situation. I don't allow the trains. I'm pretty certain, although that may just be the poor quality of British rails. But so the Australians are now investigating how this happened. But as yet, we don't know other than the fact that helicopters, it's bad when you crash them into each other. Yeah, don't do that.

Don't do that. Well, there's your problem. Top tip, don't get in a helicopter if you can avoid it. Yeah. And if you do try to like, I mean, this is a valuable example of like passenger assisted see and avoid, right? Not successfully. But, you know, if you as a passenger can see that the aircraft you're on is about to crash,

it's probably a good thing to like give the pilot a heads up. And so, you know, very helpful. So wait, was the was the helicopter that crashed and killed everyone? The one where the pilot gave the got the heads up or was it? No, no, that was the other one, I believe. So I believe they they gave them the heads up right before the the helicopter that killed everyone like crashed into it. I see.

Well, well, yeah, that's yeah, I saw some of the stuff about the people involved and that was pretty tragic. In other news. There's weather. Weather is occurring. Weather did happen. This is like the second instance of weather in the United States

in the same week, I believe, because previously the East Coast got it. And now the West Coast had a bomb cyclone, which we didn't get shit here in Philly. We got like a little flurry for a couple of hours. It was over. Meanwhile, Buffalo is like trapped in a big block of ice like the end of the shining. Oh, yeah, for the second time in the past couple of months. You know, it's almost as if there's some kind of climatic

instability occurring here. It's like there's weather could be more often. I don't know if anyone's noticed this or thought about this. Maybe formed a sort of international working group about this. It's it's fascinating, isn't it? How the sort of yeah, that's I mean, I don't know about anyone else. I'm I'm somewhat getting quite accustomed to these once in a generation events that's I mean, I don't know if it's just me.

If I'm getting old or whatever, you know, every year, the one just rides you down once in a generation weather event seems to come around earlier and earlier. Yeah, it seems like I'm I'm living through one of those one in a hundred year things pretty often every year. Yeah, that's what shock said is that, you know, climate change is basically just watching the planet be destroyed through cell phone cameras until you're holding the camera.

Well, like, you know, I just want I just want some snow to happen here. And, you know, what happens instead is it's consistently like fifty four degrees in January. I mean, my God, it's just lame. Yeah. Yeah. But so the worst part is if you believe in sort of like radical optimism or like climate optimism or whatever, then that that requires you to go. This is all locked in. It's going to be like this like forever now.

This is normal. Therefore, it is time for us to exert sort of maximum effort to make sure it is only this bad plus as worse as it gets, like, until it bottoms out, you know? And I put down there's weather because like all of this shit's already locked in. This is happening, whether we make it worse than this or not. And eventually we're going to have to do like covid. We're going to have to like stop considering this as news in order to like cope with it psychologically.

Otherwise, it would be all the news that there was. If you remember that that New York Times front page that was like here in the New Yorkers who have died of covid and like really small print. And then they just the number of deaths from covid in New York just like quintupled after that. And yes, well, OK. What are you going to do? Well, it's weather.

My joke for this is that God sent a storm to kill Jeremy Renner, but instead he got Ken Block, which RIP is very sad. Snowmobiles also very dangerous machines. You know, be careful with those two. I was about to say people seem to get that get themselves killed on snowmobiles like constantly. I was not doing tricks with them. I was looking up to see which was

invented first, the snowmobile or the jet ski, but it is actually the snowmobile. So the jet ski was invented as a safer alternative to the snowmobile. Wow. I mean, those things in ATVs as well, like just generally any sort of equipment that you put a powerful engine in, then you don't really require that much training to let people use is fine. It's normal. And, you know, this is just going to just continue.

And it's up to you whether you get like whether you live in a climate change zone that gets this kind of fucked up weather or Philadelphia, where it's just like it's just hot in the winter. It's just it's just yeah, it's just 100 plus in the summers now. Yeah, miserable drizzle. Just constantly the cold cloud cover for for like months on end. Everything's gray. But the living Nova Scotia.

Yeah, I do want to say that, like, obviously, you know, it's it's hard to just on a personal to like the grind of this is so fucking exhausting of like watching, you know, everything just sort of go up and smoke and people might give a shit about it. But I know I'm not I'm not even saying that to be depressing. I'm just saying that to be like, you're not the only person feeling that way. I mean, I'm and I suggest personally what you do is you will have to bleep this, but I'm doing it for me to go to the Exxon Mobile CEO's house or houses

for whichever and Saudi Arabia with the Katana. No, no, no, we're not doing Katanas. That's inefficient. We are doing any one of those cobbled together. Howards, baby. Howards and what you do is you you usher his into the basement. And you say, stand right here. We're going to and then you just like it's a 90s RPG.

And this is going to be a long bleep. Yeah, good. And then you you out on the front lawn, call the news and say, hey, CEO of Exxon Mobile, I and you might want to come quick. His entire family's and then you repeat that for Royal Shell and whoever the hell else. And then you take the entire Congress and once again, you will get a halberd for this.

Let me I'm sitting a record for longest bleep, Alice. How could I have had a very frustrating week? I don't think so. I think I think the path to progress is like moderate reforms within the law. I think if we like sort of petition the government peacefully for a redress of our grievances, we could we could change the system from within. That's right. That's why I've become a police officer.

Yeah, Alice, if you considered if you considered getting a petroleum engineering degree, Alice. It's strange. It's almost as if people think that a claim. Why have an oil field for you to blow up? It's curious. People almost seem to believe that an oil company executive could not be a socialist revolutionary in a third piece of news.

Oh, fuck, where'd I put the news button? There we go. This guy is in hell. We put this guy in a living nightmare. Yes, this has been his own creation. This is this is like watching the Republic fall apart before our eyes to these dweebs sucks. It'd be cool if we were doing it, but like watching this guy

with that fucking shit eating face, knowing he's about to just scoop more hot shit into his mouth. This is a goddamn delight. This is Kevin McCarthy. He is not the House of Majority Leader. He wants to be. He wants to be the leader of the new Republican majority in the House of Representatives.

However, they have to vote for him to do that. And he has been experiencing sort of permanent nightmare where all of your colleagues get together in a room to vote about how cool they think you are and like, do you can't get a majority of them? Like, yes, because they think other guys are cool. Yeah, the House Freedom Corkers thinks that Trump is cooler and thinks that like this guy's woke and he's going to do gender to them. And so they've been they've been refusing to vote for him.

Most noticeable is Matt Gates or Gats, the sort of like wrong aspect ratio looking ass. Yeah, you could say you could say that. Yeah. Are we are we able to say that? I'm not sure. Oh, yeah. Yeah, he's a better file. Yeah, he's a better file. Also, we have to back that up. Yes, we have we have criminal investigations to back that up. Oh, OK, OK. I was I thought you were just doing more beeps.

But no, no, dude's a straight up pedophile. Wow. So yeah, you need you need a good pedophile to fight the bad pedophile. Really good. Yeah. I don't really know where to go with that. Yeah, right there on the wiki page. Federal investigations into sex trafficking. We can call him a pile. Wow. OK. Well, in any case, Matt, Matt, Matt Gates and his his caucus of freaks

and weirdos are like refusing to vote for him. And all the Republicans can think to do is just run it again, run it again, run it again. We've had what, 12 votes now? We're going into we're going into 14. Yeah. 14 times the charm. Yeah. He's back. Gates is married to the dweeb that invented Oculus, that guy's sister. I'm a lucky.

Yes, I hate that I know. I don't want to say his name. I hate that I know the guy who's most recently in the news for inventing an Oculus headset that will kill user. Yeah, kill you if you if you die in the game, you die in real life. Yeah, that guy. Well, what I think is interesting about this whole vote situation is that, you know, once once like they they elect a speaker, the entire purpose of the Republican majority will be to prevent

any legislation from moving forward. So they don't actually have to elect a speaker because that has the same effect. Right. Yeah, you know. But I think, you know, maybe even more effective to further their agenda of blocking everything is just to continue this through another two years. Yeah, we know, you know, Republicans in the House would not be able to do very much other than block legislation handed down by the Senate,

regardless of the outcome here. So I think, you know, this is going to probably go on for a while. I think it also adds a nice so fun thing, which is the Hakeem Jeffries can't be House Minority Leader yet, which is really funny because he shouldn't be. He's he's terrible. And therefore, great, perfect. You know, anarchists, the anarcho-Republican party. Yes. I'm so enjoying that we sort of had, you know, over the summer,

sort of our own sort of little contest of just backstabbing and chaos with the Tory party leadership election. It's nice to go across the pond to sort of just, you know, once again, America just does things bigger. So, you know, yeah, yeah, it's lovely to see sort of someone else's completely impenetrable, internasine process for selecting things. Do they have to? How do they vote?

Do you do this sort of computerized or they have to sort of stand up and walk through a lobby? You have to stand up while a guy calls your name and say I or nay. This is why Kristen Sinema did the sort of like sassy thumbs down thing. I think it depends on what the vote is. Right. They do have buttons at their desk, right. I believe. But some some votes are, I don't know what they call it, like a roll call vote or something where, yeah, you have to physically go up.

This is great. That's what the Democrats are drinking in the chamber or something. Do you think they're bringing popcorn? Which is probably that's what I would be. A couple of them were drinking. I would be drinking. I would be drinking. I would start drinking again.

And just spitting out, just spitting in a cup being like, y'all ain't voted yet, huh? You wouldn't even have to use a cup because I think Congress still has like congressionally mandated civil war era spittoons. I think if you were paying attention at our live show, you would know that they do. Yeah. And I'm going to say, you know, I was I was 70 percent

aware of that live show. It was mostly chance. And to be honest, yeah, you fuckers love a chair. Yeah. Apologize for not getting recording then. But anyway, we didn't try. Just so you know, yeah. The the you know, the the net the net effect of this is

we're just not going to get any post office renamed for another two years. You know, yeah. We can also get the post office. Third August in October to be you know, the third August in October. But yeah, the third August in October is the third national time day to a great national calendar calendar literacy day. Oh, I mean, I mean, such a frame of mind for this.

Yeah. This is the I mean, this is the sort of thousands in some things day of March, 20, 20. So I mean, at this point, yeah, yeah. It's been 2016 for a million years of a million years. It's been one week. You know, that came out like 23 years ago this week. Oh, no. Wow. Wow.

Can we learn to make the third August in October national weather is your problem day? I think you do it right. Yeah. Yeah, we can ask him. I mean, yeah, that's all. That's turns 25 this year. Sorry. Wow. Oh, well, very hard work.

Anyway, it'll probably it'll probably be another five years before they elect the speaker. And I for one, I'm here for it. I think it's very funny. Absolutely. I just just want to watch those numbers go up, you know. Anyway, that was the goddamn news. All right. All right. We're doing here. OK.

Pretty colors, pretty colors. Yes. Listen, this this is the only bit of my day job. I get to talk about it. So this is this is this is nature's order. OK. Well, yeah, this is this is nature's and engineering disaster. This is cancer. Hmm. Oh, this is the thing that I think I have every time I get

like a slight twinge anywhere. Yeah. So this is this is so on the specifically on the left. This is what's called a ductal carcinoma of the breast. And on the right is a Hodgkin's lymphoma. So that's that. So I'm not going to go into the too much into the specifics of those cancers exactly, because each of them is at least a sort of three hour presentation.

So basically cancer. We have to ask ourselves, what is what is what is a cancer cancer? Basically, it's a it's a Tropic. God damn it, dude. So it arises when there are failures in process, failures in process during cell replication. And this is basically occurs in one of two ways. You either have mutations that are present from birth and those are

called germline mutations. So like the Bracker gene, right, like Bracker, like Lynch syndrome in bowel cancer, in dimitrile cancer and then somatic mutations, which are ones that occur sort of throughout life. You acquire them as you the older you get, the more things can go wrong. Hmm. So I've written, I put recapping a bit of basic biology here, but given the standard for basic biology has been set so low.

How of how of you as our listeners that standard beneath even that? I mean, yes, I mean, I mean, let's say I know about how my body works. The happy I am this is this is where it gets kind of terrifying, because this is when you find out that a lot of stuff is kind of. And there's it's it's all under the control of sort of proteins. And there's no fuck. Those guys, Jesus, my God, it's not a car. It's not really because it's not really a sort of conscious process.

And and even less than that, it's literally just due to like these things have to be folded in a certain way. You think that you're like a guy wrong, incorrect. You are like 15 trillion little like miniature guys and they're all doing their own thing. Your body is firmware. Yeah. Yeah. You are at best a sort of unruly democracy of like a lot of other.

Got four. Yes. Yeah. And everyone sort of has to march in the same general direction. If we think of the body as the Stanford marching band, you think of the body as the House of Representatives, right? It has to elect a speaker. Your dumb brain is the speaker. You think of the body as one of several armies marching to the crusades. Yeah.

Yeah, this is where it was. Can't stand an awful. Yeah. So next slide, please. I recognize this guy, too. Hey, it's this guy. It's the dumb parts that make us up. Everyone's favorite character from Jurassic Park. Yes.

So this is a DNA double helix. And it's so DNA is stored in chromosomes in humans. There are forty six paired and then sex chromosomes in varying combinations. It's composed of composed of four bases and these when they're assembled along the sort of the structure of the DNA, they're in triplets and those triplets tell the molecules that are involved in replication. Those are called codons.

They they basically give a little bit of code as to where to put a protein or to start or stop reading the sequence. So when cells make proteins, the DNA for the relevant gene sort of unzips itself and it's read by something called RNA polymerase. This transfers information into messenger RNA. So this is mRNA. This is a message or mRNA.

So the the mRNA vaccines for covid are sort of a short bit of a shortcut. So so when they're injected, they they they go into cells and then the ribosomes in those cells reads the mRNA. And it's got all the different building blocks. So think about it like sort of Lego bricks, for instance, that tells it which Lego brick to sort of stack on top of the other one. Your body's dirt bag programmers.

Your IT department. It sounds a lot like a tape drive. I mean, yeah, not dissimilar. It's it's basically just gives it the set of coding. Which are OK. All storage is OK. You don't need you don't need instant access to every file you have. Tape drives make sense.

Shut up. It's OK for this. Imagine solid state DNA. Be a hell of a little more complicated. Oh, I'd be running so fucking fast. I mean, reliable, though. That's probably a good animal. That's a very good anime plot line. Let's face it.

Yeah, maybe. But so it you encodes and then the sort of it gets to the stop. This has a start. What's called a start code on a stop code and it gets to the stop. And the sort of protein sequence falls away. And because of the ways in which these the molecules in the proteins interact within the cell environment, it folds itself.

So this is one of the things that like this is why I'm the opposite of you, Justin. I like knowing more stuff about my body on the basis that is incredible. We made a computer out of meat. This is the reprogrammable, self-programmable meat computer. And it's made in electricity. Yeah. Yeah. And you plug enough electricity into this meat and it fucking paints the ceiling of the Sistine Chapel.

Like, I I do not like how you get from why I didn't study biology, buddy. Because of rules, because it rules and you're afraid of your own greatness. I think anyone has never been afraid of its own greatness. It's me. I am the most arrogant piece of shit you can imagine. They should throw a they should throw like a solid state drive in there somewhere so you can you can flash the firmware every once in a while and then reverse the aging process in our case.

Ross, you just throw it like it like in your armpit because I feel you try to install stuff like these guys from Silicon Valley are here to offer you 50 trillion dollars to try and do this because they're afraid of their own ageing place. Yeah, you just got to tell them that there's like a smoothie you can drink somewhere that's going to make all of this work faultlessly forever. And I was thinking you could do it. Apply to it.

You could do it with some kind of picture. Yes. Yes. You got to hide in your house somewhere. Yes, unfortunately, and I would recommend not looking at it. Don't look at it. I don't understand. I've never read the book. Why can't you just throw a sheet on the thing? That's what I always thought. Yeah.

But like, yes. Oh, OK. Well, then you should have put it in the drywall. Absolutely. Yeah. You got to think smarter. Yeah. Make make it difficult to access. So so hardly trying to salvage this, right? DNA DNA makes so DNA makes the proteins or DNA is the code for the proteins, basically.

And so when cells divide, there's potential for errors to occur. So next slide, please. Well, we'll talk about it next. Proteins, proteins folding, like in themselves, when that goes wrong in a different way, that's some shit I'm really scared of. That's prions. That's that is prions. Yes. Oh, no. I also wanted to say the other thing

Dorian Gray should have done, it just waited longer to look at the picture and they'd be like, wow, I'm a cool skeleton. Other than other than misfolding prions, what you can do also that fucks up is you can just go, oh, just do these proteins, fold them right. But like in the wrong order, the wrong place, you know, fold too many of them, too few of them. Yeah, I have a question. I never really understood what folding at home was. I ran it for a while.

Is that yeah, yes, that is related. That is to do with the way that I mean, that was sort of as far as we're looking into the way that proteins folded in mutations in different kinds of cancer. So so not talking about prions here, but talking about the ways that sort of when when cancer gene encodes a protein and we'll kind of come on to this, it kind of it's often the case whereby it's sort of half of one protein stuck to another protein and then it folds with

and so the folding at home thing was was basically sort of running sort of multiple sequences of these things and in a simulated environment seeing how they fold with an idea of sort of, you know, being being a sort of target specific therapies at different parts of that coded protein. Interesting. Thank you. That's right. And you can unfold these proteins again,

if you wanted, most notably by cooking, which is what makes your your meat safe to eat. Yeah. That's a this. So that I mean, that a fucking joke, I have. No, no, no, no, no, no. Meats got proteins in it, like that's what makes meat. And so if you want to like one of the reasons why eating raw meat is very bad for you, right, is because it's got a lot of like proteins, which are folded into the state that they're supposed to be in

for being in muscle tissue, which is, you know, and you have to break that down. Right. Yeah, you denature them by applying some combination of heat, burn a sauce, things of this nature, until you obtain a tasty snack that you can just digest. Just vampire the nutrients right out of it. Biology is amazing. I yeah. Sorry. And also, it's this is this takes place. And this needs a very tight range of conditions as well.

That's why. So one of the things I get really this time of year is sort of the whole sort of thing, or you should detox, or you should eat this sort of thing because it's an alkaline diet or something. I was like, juice, cleanse, juice, cleanse, juice, cleanse. Yeah. So saying you can you can defeat cancer if you make your body into an alkaline environment. It's like you literally cannot make your body into an alkaline environment. And if you do, you will die because you're because you're there is there is,

you know, several million years of evolution has gone into maintaining a very specific and very tight range of of pH within the body. So the sort of normal range of seven point three, five to seven point four, five. If you go much outside that it will kill. And that's because the proteins don't fall properly at other and the enzymes that are required to sort of break things down or go through other to other places in the body just don't work. Y'all said the risk if you had an alkaline

environment in your body and you you touched a normal person, you turn into a sort of school science fair volcano. Yeah. Just just as the full Mentos and Coke, you know, it does happen. Sometimes we don't know that has never happened as far as I'm aware. The medical industry is covering up spontaneous combustion by Diet Coke and Mentos. So the cell goes through phases through phases. And what it does is it has a rest phase, which is called G zero.

And it's not undergoing any sort of division at that point. And then it moves into a growth one phase when there's a need for it. And that's usually sort of cells, you know, depending on where you are in the body, different cells replicate at different rates. Some of them just don't replicate at all. So things like your most of the sort of neurons in your brain, the cells in your ear that have the the cilia that control the

that does the reception hearing and the sort of the cells in the retina in the back of their eye, they don't divide it. Once you once you've got them, they've got them and they're fixed and they that's it. There's those Silicon Valley guys are outside with another $50 trillion with like a project to try and get those to start growing again. Yeah, I mean, there's I'm not going to there's a there was a there was an interesting thing about sort of retina. And once I read recently, it was absolutely horrific.

But that's a that's another topic. There. So if there's like a tissue injury, something like that, your skin cells, your soft tissue cells underneath will start to replicate. And those are the chemicals with cyclins. So if you and then we sort of lots of those released, if there's a, you know, you cut your hand and they'll they'll be cyclins released locally and then globally to start at sort of cells, they're replicating both sort of tissue cells to heal up the injury and also things like immune cells to go in there

and sort of clean everything up. So then you get the synthesis phase, which is then progresses on to the next stage of replication, which is the growth to phase, which is where the cell just sort of bolts itself up to prepare for the vision starts making copies of so within the synthesis phase, it makes a copy of all of the DNA in the cell to make a sort of additional copy of each chromosome. And then in the growth to phase, it's sort of it's making more organelles. So the organelles are like the little things like these are mitochondria.

Mitochondria, the powerhouse of the cell. It makes more of those so that basically, you know, you have enough to sort of power the two cells. And at that point, the cell basically has to show it's working. And I've said, sort of submit code for review. So this was that was in the phrase that was in my head at the time. So it has to sort of print out all of its code. And showed reviews, of course, yes.

For the code review, Elon Musk's cell that comes around. Yeah, well, not even a cell, not even a cell. This is under the control of another protein. This is called a protein known as PUMO, which is which is which is coded from a G called G called P53. So PUMO is the P53 unregulated mediator of apoptosis. And it checks all of the DNA at that point and make sure that basically it's it's done a good job of writing, of coding

everything on those chromosomes, exactly the same. And if there are errors, then basically it's told to go back and code this again, or if it's unfixably bad, the cell is basically then told don't do anything. You're going to sell jail. Yes. Yeah, just die. You are. Yeah, just die. You are going to.

Yeah, it's called apoptosis is programmed cell death. So. So this is the this is the this is the the commissar protein. Yes. The commissar performance review. I think of it right as the tumbler and on ask box of the body, right? In that it looks at what you've done. And if it likes it, it's like, yeah, great. And if it doesn't, it tells you to kill yourself.

I was going over there on Tumblr. So, yeah, this then ends it. So if it's everything is fine, and it's definitely fine. And the cell does the what's called the M phase is the mitosis phase. So it splits apart and into the new the chromosomes line themselves up across the middle of the cell and I think pulls apart and then the nuclei separate and then the cytoplasm, which is a sort of the jelly bit of the cell separates and then you have two cells.

And then that's my that's that's my toes. It's it's free real estate or free cells. Sorry, it's free real estate. Yeah, you have one cell just tears itself apart, two cells easy. Yeah, yeah, it's it's never go wrong. Never no, no, no, apart from what it does. I think we are to the next slide, please. Yeah, the next slide goes wrong.

Yeah, the next slide. So this is this for reference. This is a serious carcinoma. And these these occur either from the the ovary or the lining of the the lining of the the peritoneum, which the the lining of the abdominal cavity or from the fallopian tubes. Those are the places that tends to arise from. And this this actually is due to when you have one of the things that can go wrong

is that you have a a mutation in P 53. So if you have a germline mutation in P 53, which is what BRUCCA gives you, then this is one of the things that can go wrong. So like my code checking protein doesn't check code, right? And it just might. Oh, you're here again. Yeah, my my my my commissar showed too much mercy.

So eventually, what happens is enough errors start to slip through enough sort of somatic errors slip through that that you get uncontrolled division of cells. So that's one of the parts to get failure in checking. The other thing is when when the chromosomes are pulling apart, then a bit of one chromosome can get attached to another. And this is called a translocation. Now, in some cases, this is what's called a balanced translocation. So the bit of the one chromosome that stuck to the other chromosome

and then the bit of the other one stuck to the other one, it's it's what's called a balanced translocation. So it still functions the same. But sometimes then it happens in a region where you get mis that you then get misfolding of proteins or the protein kind of cuts off early or something like that. And then you get a sort of misfolded protein.

In some cases, what will happen is that the the sort of this will get recognized and the cell will be told to destroy itself again. And in some cases, it won't. And then this is this is where the sort of the checking sort of thing. But if it's three is kind of the is like is the commerce operating effectively, it is responsible for so errors in P53 are responsible for about 50 percent of all cancers. Based on the sort of current understanding we have of genetics.

So what we need is a second commissar protein to check the work of the first commissar. No, second commissar protein has hit the towers. You see why Stalinism takes off. We need an NKVD blocking detachments of proteins. Well, I think the NKVD also had commissars. And yeah, yeah, commissars all the way down, you know, I was about to say. So you really need one one sort of circle. You just need Seventh Army at Stalingrad biological Stalin.

Just just so long as like it's not at the level where I have to like individually approve cell division requests. Like I have news for you about the doctors and I'm like, I have like 16 million unopened things per day where I'm like, yes, yes, no, yes. I'll ask you a question. The development of the body is a lot like the development of the Soviet Union. Unopened emails do you have right now currently? Oh, God.

Let's see. Opening Gmail. One hundred and ninety three. Forty four thousand two hundred and forty four. Jesus, I'll be I'll be honest. You are not checking your own cell division, Liam. You you're just not doing. You need a. I have an anarchist there. I got I got sixty one thousand.

Matters of boots. Deferred to the bootmaker. Matters of cell division refer to to Puma. Yes. I've got a very satisfying one hundred and twenty three. If nothing else, a nice, nice little sequence. That's fine. I don't think any of them are of particular relevance. So anyway, this goes wrong.

You get cancer. This goes wrong. You can't answer any number of different things, which is why you're saying cure cancer is weird. Yeah, you're a virus. Yeah. So I mean, there's there are, you know, there are different factors that are involved, some sort of germline sort of mutations are, you know, to some extent, they're less of all in terms of the somatic mutations. Those are the kind of things where people say, oh, you know,

you're making lifestyle changes and all that kind of stuff. You can you you you theoretically are reducing your exposure to certain carcinogens, which reduces the risk of their sort of picking up sort of somatic mutations as you go along. Oh, we can absolutely give somebody cancer. We have that. Oh, we're going to find out how. Yes. So in terms of what we can do to treat cancer,

the body itself does recognize milking cancer cells and will try to destroy them using the immune system. So this is using mostly the sort of T lymphocytes, which are the things that are involved here, the sort of cytotoxic T cells. And what as the cell acquires mutations, it expresses the next light. Yeah, it's the next slide. It's especially sort of not starts to sort of stop expressing the self proteins on its surface, which let the body know that this this this cell has

gone wrong and cells that have gone wrong. They will start will initially try to display those proteins so that they get killed off by the immune system. But as they acquire mutations, every time this mutant cell divides, it picks up more mutations that goes along and every time it does that, it requires it acquires more and more resistance to the body's own fences. And it starts out stripping the immune system's ability to looking on itself. And it's like, I'm no longer human.

Yes. You know, and at that point, it's sort of like hoisted its own flag. It's like it's getting along quite nicely. You know, it's just it's grown itself. It's reproducing. It's it's doing its thing. But unfortunately, you know, because doctors hate fun and God forbid, women be allowed to do anything merely because this will kill a person. They're like, no, you're not allowed to do that.

We have to stop you from doing this. So we do have treatment so that broad sort of things that we have to do. We are there are sort of non chemotherapy medication. So a lot of cancers are things that are arising in endocrine organs. So organs that produce hormones, right? They arise from cells that are under the control of hormones. And so we can do things that block or down and regulate hormones. Those things like in breast cancer, a lot of things are estrogen sensitive

or in prostate cancer, testosterone sensitive. So you can use sort of this is why whenever you choose to alter your your testosterone or race or estrogen levels, they will give you a little handout that tells you, amongst other things, this will increase your risk of certain kinds of cancer. Exactly. So you change, you do change growing the texts. Don't care, but, you know, it's nice.

It was nice of you to warn me. I'm going to disregard that warning. But thank you, you know, but it will also it will one, it may increase certain types of cancer risk. It'll actually decrease others. Yeah, not a lot of trans women with prostate cancer. Some no, no, no, it's and it is the same. Medication and this is, of course, you know, on a slight tangent.

Why you get sort of certain individuals who will talk about or these are these are cancer drugs. These are hard. These are hard like so many people die after using the drugs. Well, yes, because the majority of people have cancer, have cancer. Yeah, but to a certain extent, there's actually very for sort of hormone cancers under hormone control, very successful. So you can so, you know, for sort of people with lower grade prostate cancer

who, you know, they'll have monitoring stuff and be on sort of testosterone blockers and they'll do well for several years before they start to run these problems on just suppressing testosterone. Not only is your cancer very well controlled, but you're also achieving femboesthetics, which is, you know, as far as I understand, I'm sorry. Your only treatment is forced feminization. Oh, no, doctor, don't tell me that.

And then sort of the other thing that sort of, I mean, I've got to change the order and I wrote these in because I think I think the other thing that's pretty easy to sort of understand is sort of surgery. So, you know, we cut cancer out and hope that we've sort of done that with enough of a margin of normal tissue around it and before it's spread anywhere else. So I mean, so I didn't say up top, but I said, my my job, I am a histopathologist, I'm a trainee in histopathology

and that most of my job is looking at lab specimens and sort of deciding on what sort of cancer someone has and grading it and staging it. And that helps then people sort of the sort of team meetings and decide what's the best form of treatment. And then also looking at specimens where someone has had their cancer excised and saying, yeah, there's sort of, you know, a margin of sort of one, two, three, four.

I mean, I mean, the margins are tiny. We're talking about here, I mean, sort of what it's considered to sort of accept or margins for some kind of one millimeter of normal tissue around it. But if it's a clear margin, it's a clear margin. It's sort of like you're applying a sort of a paradigmatic change to the cancer. The cancer is just like replicating itself, having fun. And you're like, I am an organism that exists on a macro scale

rather than a micro scale. Therefore, I can cut you off and throw you into the bin and you can just like exist there and die. So I mean, into this into I will into paraffin block slides, in my case, or the bin eventually, the bin in a controlled manner, according to the. No, not just into like an open like mesh waist basket. No, it's just just bins all around the house full of masses. The bleeding out, baby.

In in the operating theater, the surgeon setting up a little basketball hoop and doing like a three pointer with a like an excise I mean, I am I wish to say, I am actually an ex surgeon. So I switch career paths, but I can't really speak for that. Sort of what has gone on in the operating theaters that I've seen. Because what one of the things I have to sort of say, Barry, you know, sort of appear on this is, you know, I have to sort of any any comments

made of course, you know, in line with GMC guidelines and all disposal of tissue does take place in accordance with the Human Tissue Act. I know, which which sucks, by the way, because it means that if you get a genital reconstructive surgery or whatever they're calling it this week, they won't let you keep your balls in a jar. They won't let you turn them into like an open crater or anything. You have to send them to me. So I look at them and I go.

So, you know, take a sexual take a sexual of them and look under the microscope and go, well, you know, at least these are, you know, these were fine. You did not have cancer at the time that they were removed. Beautiful. So you're hoping to have like a desk toy of these, you know. Yeah, the good the good news is, is congratulations on your affirmative surgery and the better news is you didn't have cancer when you did. So we've got drugs, we've got surgery.

Yeah, and then we've got then we've got another category of drugs. I mean, now we get into this. This is the sort of section that is effectively this is the things we found out through war crimes section that's boy. So chemotherapy agents. Most chemotherapy agents are essentially like, I mean, all drugs are poison, but chemotherapy is kind of poison poison. It's literal.

It's it's really bad poison. And, you know, a major class of these are derived from a chemical called Mustine, which some people may have heard of. Yes, because FDR, in a sort of strange move that doesn't get talked about much, moved a shitload of chemical weapons to the European Theatre of Operations and particularly the Italian front, just in case when they were pushed a bit too too hard, the Nazis decided to do chemical weapons in the US to retaliate. And this led to the like, I may have this entirely backwards.

But the bombing of ships in Bari, Harbour in Italy, which are filled with mustard gas, which is a viscant, it blisters, it causes blisters. And this sort of dispersed over the town, killed a bunch of people, would be an episode in itself. However, one of those sort of like, sort of like long cross section studies figured out that, hey, in Bari, not a lot of people got a lot of cancers for a long time because they had been exposed to mustard gas or some component of it. And sort of from there, it was sort of derived that, hey, maybe we could use

something like this, maybe we can just gas people and they won't get, you know, like, go into remission or something. Yeah, so it basically worked. So it worked by destroying faster, replicating cells. That's that's what that's that's what it acts on. It sort of is why a proliferation affects the skin and like the inner line of the lungs and stuff. Yeah, skin lining of the lungs, mucus membranes, anywhere where there is the skin has a rapid turnover, mucus membranes

everywhere have a rapid turnover and cancer cells have a rapid turnover because they're not constrained by the body's own sort of checking mechanisms. They've gone beyond that. They just replicate. And it's why that there are sort of such dramatic sort of side effects, those sort of hair loss, immune compromised infertility. You know, you people have sort of vomiting and they can have sort of bleeding from the from the gut because all of these these cell presses are being disrupted. And it's almost kind of a bit of a race to see which it's going

to do first of all, significant harm to the to the patient in terms of, you know, the immune compromise and things like that. That's why people at such risk of sort of getting other things like, you know, mnemonias or whatever versus depleting the cancer cells. And it's often used as sort of an adjunct. So a lot of things like a lot of the breast cancer things that I see whereby people have a route have some rounds of chemotherapy to shrink the tumor down. So, you know, you may have something that's sort of five,

six centimeters and it's sort of shrunk down to a centimeter or so, which means that you can do a much more limited excision of it. But it's it is horrible stuff. And yeah, most so cyclophosphide is a very common agent. And that is the kind of current treatment which is derived from Mustine, which is the which is the sort of mustard gas. And then the final one is is is radiotherapy. And so radiotherapy, thank you to sort of, you know,

the sort of very early pioneers of radiation science. We know guys who are like sleeping on big lumps of uranium, like like, all of these things. We know that radioactivity is a fucking great way of killing cells. Really good asset. It works pretty good. Yeah, the proton therapy. Let me you just stand here and I'm going to fire this particle accelerator

at you and you won't have cancer anymore. And we'll get there. Well, yeah, we will get there because, yeah. But so sort of 19th century, late 19th century, even they had been sort of use of therapeutic x-rays and other sort of radiation for the cancer treatment. And then get the next rate is ionizing radiation. Yes, just like a form of it that's weird.

Yeah, but basically it's very similar to to chemotherapy in that it affects most cells that are replicating quickly. And the more the quicker that they're replicating, the more they'll be disrupted by the radiation. So I think we're on to the next slide where we're going to talk about. This is also how cancer treatment. This is also how cancer treatment causes huge headaches for structural engineers. Why and everything in lead?

Simply don't worry about it. You've got to design a room with like several feet of concrete or lead. Yeah, I'll let your kids like it. Yeah, so this is this is a sort of I'm going to sort of summarize here. We're talking about sort of dose effects and so. Basically measuring ionizing radiation that was sort of first used was the Roentgen, which is measures air ionization, but it doesn't mention it doesn't sort of

really account for absorption of radiation. And if a super seeded by the rat, you know, for sort of the fallout fans, this is the one that they'll be familiar with. And this has sort of been around since the sort of early fifties. And it's refers to the amount of energy absorbs and it's equivalent to one hundred nanojoules per gram of tissue.

And now this has been superseded in 1975 by the Gray, which is the SI standard unit, which is equivalent to one joule per kilogram of matter or one hundred rads. But, you know, this is an SI unit. So the United States still uses rads because of course, of course, a metric system. Yeah. Yeah. So the other thing to bear in mind is also the radiation dose is not just an expression of these all doses.

How much is this, which is the biological equivalent dose, which is, which is measured in another unit could see that with one see the equivalent to one joule per kilogram, one gray of human tissue with different waiting factors being applied and that on the tissue being exposed. Yeah, I'm wearing my like, you know, a cool shirt. I'm wearing my like, you know, sleeveless lead t-shirt. Right. My equivalent dose is going to be much lower

under my like lead t-shirt than it is going to be on my arm. So. Yes. So you can what it basically means is that it's that you can sort of have the sort of big whole body radiation dose. But if it's sort of constrained to us, but if you're constraining that dose to a small area, then you can use higher higher doses. I mean, we'll talk about that more, I think, on the next slide. But the sorry. So we have like some coefficient here that is

corresponds to different types of tissue. Yes. This is what I'm saying. OK. Yeah. The different tissue absorbs at different rates, which is the which is which is why that they will sort of get on to the design of some of the machines used to treat this in certain ways. I think I think we're on the next slide. So this is sort of whole body radiation dose effects. People will still be like,

why does my, you know, dentist step out of the room when they do the X-rays? What the fuck? And and first about that. It's it's and that's mainly because the sort of the radiation dose is stochastic. So the more doses you are exposed to over a length of time, the more they build up within the body. So explain to me in sort of in idiot form one time, very effectively,

I should say, which is if you if you go to a bar and you have a drink, you're going to be fine. If the bartender has a drink with you, he is also going to be fine. If the bartender does that with everyone who comes into the bar, they're all going to be fine and he's going to be dead. And I found that a very like effective illustration of why you're going to step out of the room. That if that's a sort of illustration that I'd had sort of during my

medical imaging science course, then I might have done sort of better. But also that would have required me to have not had undiagnosed ADHD and not got hopelessly addicted to Eve online. A killer on both counts. Oh, yeah, that's that's that's a way to that's that's a way to waste a lot of time. I request. Yeah, it is. I mean, you know, I could have been doing sort of, you know,

boring work spreadsheets, but I was doing exciting combat spreadsheets instead. I've always been afraid of touching that game because I know I'd never be seen again. But I wouldn't know you wouldn't. I've seen you play goddamn. What's it called? What are you like? Factorio. Yeah, there we go. Yeah. Yeah, I don't want to touch that because it feels like it's a I, you know,

I'm sort of coming up to my sort of in the process of doing my final exams for the however many time it is when this goes out. But yeah, I just have to sort of steer clear of that stuff for the for the time being. Medicine in general just seems like one of those things where it's like you're really good at homework, so we gave you some more homework. You like doing exams? We got we got 50 more of them and they're incredibly important. Yeah. And and not to mention that, it's like,

you have to pay for them yourself as well. There's, you know, it wouldn't it wouldn't be a profession in the United Kingdom if it wasn't incredibly unsustainable to like do. No, if it's it's the thing that sort of people sort of on a slight tangent always seems to think I would say, oh, your hospital pays for that. You know, no, no, no, they don't. That is that is, you know, they they expect me to pass them.

But they in no way do they want to pay for me to do them. Anyway, awesome. It's all like, except you actually, you know, contribute something useful to society. What you're paying for was to sit exams. What I was paying for was to like go to dinners. I mean, there are it's not to say that there aren't dinners. Just to, you know, we'll be right back.

Keep going. OK, so I mean, in terms of exposure risk, then there's a measure of both the effective dose, the time exposed for, and the number of doses. And we have pretty good data on what constitutes harmful doses of radiation. We're going to survive a surprising amount sometimes, too. You are and sort of and what turns these and distances to sources. And that's mainly due to this is the second bit of war crimes,

the development of nuclear weapons technology for those. Oh, so so when the sort of prototype nuclear weapons, Liam, we're here right now, he'd be arguing. Yeah, we lined up a bunch of conscripts, a bunch of countries, including the UK, and just like it went. OK, close your eyes, the nuclear weapon. We didn't even tell them the nuclear weapon was going to go off. They were like, hey, we're going to deploy you to the Caribbean for a bit

and you're going to stand on this island. Don't worry about it. And the next thing you know, a nuclear weapon goes off like 25 miles away. But it's sort of in terms of the sort of up close doses, that was sort of stuff like the the the demon core experiments. Oh, yeah. Yeah. How could you give your own scientists slow and the spicy core? This is what I'm getting is that the the deadly joke from

Manny Python, where they just tested it on a guy, was real. Just with this has been a personal interest to me. But there's a whole load of shit, particularly in the early Cold War of the 50s and 60s. We're like, if you were in, say, the US Army in 1960, that's a decent chance. Your immediate commanding officer was a six foot tool sculpture made of uranium as part of a long term study by the CIA to see how many different kinds of cancer they could give a person.

So so they did that in Iraq, too, but with burn pits. The the other sort of the the the demon core is sort of a fascinating bit of thing, because it's basically two two big hemispheres of plutonium with a sort of on a shaft and then shims inserted at sort of every sort of few millimeter intervals, and they sort of remove these one at a time to see at which point this thing starts to become it starts to sort of to react. Critical critical and there are two incidents that occurred and one of which was when

everything sort of fell out by accident. And then the second one of which was that someone had kind of invented their party trick of they get everyone in the slow zone. Yes, yes, everyone get everyone in to demonstrate. You know, and they look, you know, we go moving the court. This is where they got the Geiger counter here. And this is where it starts to go clicky. And he just flick the shims out one by one with a screwdriver.

Until he unfortunately flicked all of the shims out with the screwdriver. And the top half went on the bottom half. And he sort of dived over it to sort of. Nice, I'm considering nice and considering managed to sort of prize these two things apart and then sort of having calculated where everyone else was in the room relating to him. And the sort of there was a as I understand, there's a sort of army colonel or something sort of standing behind him.

They had an idea of how much radiation sort of his entire body had absorbed. And then how much the guy behind him had absorbed. And then I think there were two other people in the room, how far they were from the source when the thing went critical. And that sort of gave some useful information and then the other useful information was how long it sort of took the. It took him to die after sort of radiation sickness. Yes, this is this is one of the worst ways.

This is this is this is down the bottom of our chart here. So, yeah, this is sort of, you know, this is the the absolute sort of this is this is lethal dose of radiation. It was very short. Pleasant. There's no pleasant radiation sickness, obviously, but you read like accounts of some of these things and like this will come up when we do Chernobyl as well. But some of the time it's like I had what I thought was a cold, right? And then the far end of it is this thing where it's like, OK,

the Chernobyl mini series was not accurate, like in terms of you don't turn into like a big piece of like melty beef jerky, right? But it's like uniquely unpleasant and also takes a long time as well. Like as we see him measured in days. Yeah, it's extremely grim. So that's that sort of whole body doses. So when radio therapies, we were only talking about a very small volume of tissue being targeted, so while higher intensity

amounts of radiation are used as under normal circumstances, only being applied to a very small amount of total body tissue and the adverse effects are limited. It's not to sort of say it's completely eradicated because it's not an incanses that treat the body of therapy, which will have temporary effects in terms of immunosuppression and can get secondary cancers as a result. So the most common of which is something called angiosarcoma, which is a tumor, which is sort of a blood vessel, effectively a blood vessel forming tumor. And it's not nice and it does not do well.

One thing that's sort of noticeable. Invented by big radiation. So you'll do more radiation treatments after getting radiation treatment. What's interesting to me is the extent to which there is sort of like very obvious feedback from radiation for a lot of the time. Like I mentioned, people not knowing that they had radiation sickness before. We've talked about that and going on and stuff. But like a lot of the time, radiation workers and stuff will know very clearly

that they have been exposed to something because not only will there be like a bright flash and you'll taste like metal, but like a lot of accounts of people who have died of like acute radiation sickness, radiation syndrome, whatever they call it now, have been like, yeah, they just know immediately that you have been heavily irradiated because you can feel it happening to you. Yes, the same thing. The same thing is true on low doses. Like there is an X-ray feeling you can get.

Like if you sometimes imagine like that scales up, you have to imagine, even with your sort of like precisely targeting the big Dr. No laser, it's not the big Goldfinger laser at you. So I think I think we're on the next slide. Right, so all the animation. Lego, we have a cool Lego diagram. We have a cool Lego. We have a cool, you know, can we say Lego?

Connecting. I think we can say so. A social democratic Danish brick building toy diagram of a radiotherapy suite. Yeah, and as Justin was alluding to earlier on, there's this sort of wall around sort of very thick concrete or lead or sometimes concrete and lead and a big corridor with a big door at the end of it. And there are no windows between the between where the

operator sits and where the therapy happens. And like the extra line, like a sort of like a light trap for film where it's like, I mean, it's very applicable to radiation, but like where it's like at some point in the distant future, archaeologists will look at this and be like, this was clearly like a ritual chamber of some import. You know, it has like a sort of as mysterious arrangement of passages and very thick walls. It's the it's the it's the labyrinth, isn't it?

It's the labyrinth of Minos, which is sort of it's a very complicated palace design. But it's a sort of people who've come out of the Bronze Age collapse. And it's, you know, this is this is this is to contain a beast. Going going very sort of ancient aliens and being like the system of passageways and like inlets and pyramids to let your ferro's car escape is actually an ancient radiotherapy suite. I was about to say that. Yeah.

Why do you think they built them so heavily, you know? Really high energy radiation. We're talking like neutron star. Yeah, it's an particle accelerator. So here's what we've got with sort of two main therapy sort of sources here. We've got either got spectrum radiation, so that sort of x-rays and gamma rays or particle therapy.

Both of them require the use of this thing, which we sort of alluded to earlier, called a linear accelerator. So, you know, people sort of thought about, you know, know about sort of like your CERN kind of thing as a thing about a particle accelerator being that. But this is this is a particle accelerator. So you have a gun that's sort of an electron source. And then the reason for this sort of on and off sort of rotating diagram is you have sort of multiple magnets set at different

electrical potentials, which accelerate the electrons. And it's essentially sort of relativistic, about a millimeter wide, constrained in a narrow beam with the electromagnets. And we measure the energy in which these are generated using something called electron volts. So an electron volt is the energy required to accelerate one electron through an electric potential difference of one volt in a vacuum. These are going through like, you know, in a video game,

we have to like sort of like lines on the floor that like lice up and flash with a big arrow that like speed you up. This is wipe out for electrons. Yeah, exactly. So they're just going faster, faster, faster, faster, faster through this beam. And then the majority of the accelerators for sort of imaging work in the sort of taking X-rays for sort of, you know, you need to get a chastich or something.

That's sort of in the kilovolt range, kilo electron volt range rather. And in the therapeutic range, we're sort of talking about the sort of mega electron voltage. So the beam, the beam itself can be therapeutic. So that's what we're talking about particles so that you can you can move the beam around sort of using these are called scanning. Is it referred to sort of throughout the sort of terminology we're using here is

scanning and like bending magnets or sort of some people just use the term Wiggler's to sort of move. Yes. Thank you. Finally, the bad and naughty electrons get put in the electron Wiggler. They get put in the electron Wiggler. And that wiggles the beam around and it and over and they sort of

folkly, they sort of distribute the beam energy across an area. So the way this is sort of set up, they sort of go in a sort of a grid or whatever. So it sort of targets the tissue and it does that. The the the two sort of the indications of these are that you've got stuff that's kind of on the skin surface. Then you can sort of use sort of X-ray therapy for that.

Because the skin is quite good at attenuating X-rays. So the X-rays are kind of you can't you can't treat stuff at depth with X-rays. Whereas with an electron beam, you can actually target the depth at which you want this thing to to hit. So the electrons will kind of miss stuff on the way in, but then hit a cancer that say a couple of centimeters under the skin. Wow.

So you've got electron beam mode, which is it's kind of, you know, firing the beam through the through a sort of portal, which can move it around. And then you have an X-ray mode and to to produce X-rays that the linear accelerators fires a beam of electrons into a tungsten sort of target. And the tungsten is used because it has a very high melting point. So high energy electrons hitting at a relativistic speed don't melt it. Next slide. Yeah, next slide.

Oh, we. This doesn't come out so well on the white on the black background. But yeah, we may have to mess this around in post. I don't know. I don't know if post happens. I'm not sure if an image post happens. Certainly audio post happens. An image post definitely happens because Devon puts Devon in in the podcast sometimes.

Yeah, of course. OK, fine. Well, in that case, we can supply a screenshot of the original. Yeah, sure. So I'd sort of done I think it sort of indicate what happens where basically you this we're going sort of as you fire your electron beam at your tungsten target. And then X-ray photons are generated by one of two means. And the remembering that this is now we've now gone from basic biology to basic atomic physics.

So I'm still stuck in military history. So I'm like, yeah, of course, the round hits the tungsten plate causes spalling, which kills the crew. So the the electron, the electron that's been fired by the linear accelerator, smashes into one of the electrons in the lower orbit of the the tungsten atom and knocks it out. So the way that things work in physics is that things want to be going from the highest energy, things that are in high energy states want to be in low energy states.

So as one of the electrons from the outer shell moves down to replace the electron that's been knocked out, it emits an X-ray photon and it gets rid of the excess energy. Then you also get a phenomenon, which is called Bremstrahlen, which is as the electrons from the linear accelerator are slowed by the mass of the tungsten nuclei, they lose energy. And again, that lost energy is emitted as an X-ray. And that's kind of about 80 percent of the generated X-rays. That's not really targeted.

That's kind of the background radiation. It's very, very inefficient. So about one percent of the of the input energy here is emitted as X-rays and 99 percent is lost to heat. And so to account for that, you have to increase the power of the beam. The current of the beam is about 100 times higher in X-ray mode compared to that of the electron beam to generate the same output voltage, basically. So 25 mega-electron volts of X-ray energy takes more input energy from the linear accelerator than the now putting 25 mega-electron volts of electrons.

Raising my hand for a question here. Sure. You can target the depth of this when you're using it with like a like, if you're using this in a particle setting, right, and you can target the depth. Is it not like, is the advantage of using this on sort of like skin level with an X-ray high enough to make it worth all of this extra bullshit that you have to do, including all the extra power? This is where I sort of start to fall down.

Because my my clinical experience is not that of sort of radiotherapy. What I know is, you know, this is from sort of going into this. This is basically having the sort of dual mode gives you sort of a range of treatment options. And it's by whether you're treating like the what the electron beam as I understand it can treat is quite narrow and quite small. I see. Whereas people do get like, sorry, go ahead. Whether it's X-ray, you can you can effectively sort of a radio sort of a field.

Very, very inconveniently, people insist on getting a bunch of different weird cancers in different places and times. Yeah, they happen in different places at different times and. Rationalize this cancer thing. It's very inefficient. My question is, if you had a machine that does both of these things, they're on separate circuits, right? No. Right. Never stops, baby.

Well, no, I see some problems that could develop here. So this is that. So the so I think we maybe on to the next slide. Yeah, it's time for us to go to Canada and we must ask Canada. It is. Riley. A miserable pile of secrets. So that so the.

After the war, there was a crown corporation established in Canada, which is a sort of crown sort of crown corporation. Canada is obviously a part of the the Commonwealth and so the Queen is still ahead of state. The crown corporation is basically a sort of as I understand, sort of profit generating entity that's got sort of some amount of was I nationalized like, yeah, please see more for our for our yeah,

our Newfoundland rail episode at Canadian Nationals, the Crown Corporation stuff. Like it was, it isn't anymore. It's sort of organized the same way M track is. Right. So so so this is so ACL, the atomic energy of Canada limited was set up in the Amtrak of smashing atoms. The Amtrak of smashing atoms for specifically non-military nuclear energy devices. They developed us a. Early sort of civilian nuclear reactor, which was called the NRX.

Neoreactionary nuclear reactor. Peter Teal was actually generated in this. So this this this this first device, the NRX, had a look at in Chalk River, Ontario. This underwent a partial meltdown due to insufficient cooling. This resulted in contaminated water flooding the basement section of the reactor. Among the military personnel involved in the cleanup was one Lieutenant James Carter of later peanut farming and US presidential fame.

He was a new guy, wasn't he? He was a new theory of submarine. This is this is this is where he kind of made his name as the sort of as the head of the as part of the cleanup detail for the honor for the NRX. But yeah, this is this. This was sort of where he sort of started comes to prominence. They then developed another design called the can do nuclear reactor. This is all. Yeah.

Can do the reactor. Yeah. Canadian like depleted uranium, I imagine. Yeah, deuterium. Yeah, deuterium. OK. Yeah. It's it's fun because you can't make nuclear weapons with it. Yeah. So so you can sell it to developing nations without as much

of a proliferation risk. I miss the heavy water. It was much more evocative. This is that this is a sort of the signature product. And they are as far as of 2011. They remain a crown corporation, although in the same way that a lot of, you know, formerly sort of national type corporations have gone, they've sort of been they're all their operational

activities now privatized, sort of they brought in Canadian equivalent of capital or whatever to actually sort of run the day to day pieces. Yeah, I used to be all brought to you by. Yeah. Yeah. So and then they did, you know, there's a lot of this, you know, for the, you know, yes, they had this sort of asset. This is all kind of reasonably sort of good stuff. They did a lot of manufacturing of medical isotopes.

So things like Cobalt 60, Malibu 99, which is a which is a contrast agent. So in MRI imaging, you can't inject any sort of dye because that, you know, it's all to do with sort of proton weights and stuff. But what you can do is give people Malibu 99, which has a heck of a lot of weights in it, and that is a very dense injection. Yeah, it gives you basically sort of dense in a sort of in a in sort of nuclear, sorry, in nuclear medicine, rather.

So yeah, it's a kind of contrast agent, you know, a conventional dye won't work. But if you give something that's heavy and radioactive, then it will show up. And then they developed linear acceleration technology for bracing radiotherapy in conjunction with the French company. The Compagnes Générale de Radiologie, CGR, and they joint marketed a device called the Thera Exit, which the French way in the beginning, which is the way in the beginning, the big sewing machine looking here, which, yeah, the black and white images do not color, do not cover the sort

of lovely color scheme. I'm getting a bit more of a stand mixer vibe from this, honestly. Yeah, I can see that. It's it is your it is your, you know, it's the it's the the KitchenAid, isn't it? It's the KitchenAid. Yeah, I mean, imagine you could put some like flame decals on the side here, you know, they're going to they're going to attach the like dough hook and they're going to

fucking whisk the shit out of the bar. Oh, dear. Oh, no. So the the the the French name this much. This this was a I don't know who was sort of here, but whoever was sort of working at sort of ACL was sort of very much a sort of. You know, pragmatist, pragmatist, sort of like a loose French guy being like every

because this machine is Neptune and then, you know, some Canadian guy from Ontario called like Dave is like, okay. Yeah, it's that it's the it's the therapeutic accelerator and it outputs at six mega electron volts of X-rays. It's the Therax six. Beautiful, poetry, poetry all the time. Beautiful. And then so they added in so they took

the French machine, the Neptune and they added computer control elements. So they they they sort of added they had a rather than the operator sort of have to sort of set everything up manually and then sort of go out the room and just sort of press the on button. They sort of had a connected this to a PDP 11 mini computer in sort of relative turn because the sort of the mini is about the base unit is about the size of a domestic fridge.

Oh, I mean, that's that's many in that you don't like a computer building, just a computer room. You don't need a computer building. And then then that's attached to to a to a terminal, which is in the operator suite. And then this was superseded by a second generation machine for the Therax 20. This was another CGR design. This is the Sagittare. Even even nicer, you know.

Yes. Yes. We're going to put you in the Sagittare. I sound sounds delightful, sounds luxury. It's like, oh, you're going to put me in like this suite of the luxury suite of a hotel room in Tahiti. Fantastic. Yeah. This mini fridge that will stop your cancer. Yes. Exactly.

Regular fridge, whichever. So this this was macro fridge. Macro fridge. This is a kind of a bit sort of more marketing this could do both x-ray therapy and electron beam therapy. So this could do deep tissue. So the Therax 6 was an x-ray based machine, it could do sort of field treatment, but not deep tissue treatment.

Whereas this was like, well, OK, we can do the field treatment with the x-rays, but we can wrote. We've got a sort of it contains the sort of head around on it. So that it dies as you know, it's removing some horseshoes. This is where you know, you've got you've got your dough hook and then you've got your mixer attached. Yeah. Yeah. Exactly. So that's so you do this by basically you've got a head

on which we can sort of see here on the on the sort of the six, the sort of the business end of it, where you can rotate that around. And that's but the problem with it is, is that all of this is made out of steel and it's got a huge lump of tungsten in it. And then on the other side of it, it's got a counterweight for the tungsten, which is iron or concrete or something extremely heavy to balance it. And there's things all on rails and it sort of rotates around and blocks into place. And again, this was this was controlled by a PDP, a mini computer.

So we'll move on. I think we're on to the next slide and we're on to. Oh, no, this is the beautiful little computer. This is a piece of this a lot. Yeah, it's a hour and twenty six minutes in the subject of today's episode. The subject of today's episode. And I have to say this. So you've got this beautiful little, you know, VT 100 terminal emulator.

Well, no, not even terminal emulator. Sorry, I say terminal emulator because I when I graduated from medical school, we were still using a VT 220 terminal emulator for sort of getting results of stuff from the lab that has really. Yes. Yeah, so so so that was so that was back here. There's a quick digression into IT in the in the NHS when I graduated from medical school in 2007.

They were still looking up results on a on a VT 220 terminal emulator, which is running in DOS box. Amazing. Beautiful. Yeah, we are now in 2023. And most NHS systems are just about running Windows 7. Wow. That's terrible. Yeah, the United Kingdom of Great Britain and Northern Ireland.

There are there are the most advanced I've got was when I did one of my exams and I have a laptop for that. And that was actually on Windows 11. And I was like, I didn't know what I was doing because, frankly, like, where's the fucking start button? Where? Yes. So then you've got this the the actual computer itself, which is the thing with the tape drives and and beautiful pink trip.

Oh, yeah. Someone color coded that. Yeah, this is like the pencil like. Yeah, full. Kind of, you know, it's the early 80s. We are going to have our sort of we're going to have our synth pop on the radio and we are going to have our synth pop themed mini computer. And then this is the only. So, you know, for an example of like, you know,

people have been calling out for this and it's all about this is going to go. This is the only extant picture that I could find of a Thera 25. But if you if you put their act 25 into Google image search, you will get lots and lots of pictures of other linear accelerators. And people go, oh, this is the third. No, I very much tried to do my due diligence on this and find a picture of one. And this thing has been scrubbed from existence. Wow.

You can find the third act six. You can find, I think a couple of pictures of the Thera 20. The Thera 25. This is the only picture, which is an artist's impression from a promotional brochure, which is held as part of a library into the atomic sort of atomic energy archives of Canada, I think that's the source of this. And it's the only extant sort of picture of the thing that exists.

It's just like grainy drawing. It's it looks more hostile than Thera six does, it looks a lot less sort of. Yeah, yeah. Because sort of ominous cantilever, you know? Yeah, yeah, yeah. So this was a mind of like ancient Egyptians again. I'm not sure why they those over this point.

This was developed independently by AECL. So they'd ended their partnership with the CGR, the French company. It wasn't named like this. Le Sudicatrice or whatever. No, no, this is your Canadian. Oh, this is this is the Thera 25. It does therapy at 25 mega electron volts. Does what it says in the tin.

It was so this was using their sort of they patented in the 1970s, what was called a dual pass linear accelerator. So basically, you it fires the electron beam through that system of alternating electromagnets twice, which is why they can get the way they can get the therapy for mega electron voltage up to sort of 25 me fees. So and and it's and it can do 25 MeV x-ray and it only does 25 MeV x-ray because that's the energy it takes to that's, you know, using putting that's the maximum sort of beam output to generate

that 25 MeV or electron beam therapy for five to 25 MeV. And the reason you vary the the mega electron voltage is to sort of, you know, account for sort of depth, tenuation, different types of tissue. And the other significant change is that this was built from the ground up as a because this is now the sort of early to mid 1980s. This is a fully software controlled system. Oh, no, it's going on the computer computer.

No more knobs and buttons. It's all going to be controlled through this little terminal. Yeah, it's the future. We do things with computers now. So it's fully software dependent, which responsible for both the machine operation in terms of setting the the voltage of the treatmenters and then also responsible for the safety systems. Because in the previous case, that used hardware interlocks, which the system

software had software checking on it, but it was backed up by hardware interlock. So the thing physically wouldn't fire unless it check, you know, there is a switch that says the heads in the correct position, the beam set correctly. It won't fire. I'm going to shout someone out now, specifically because there is one person who's who's basically on the bulk of work on sort of contemporaneous documentation of the Therac 25. And that is Professor Nancy G. Leverson.

And she is currently still working as the Professor of Aeronautics and Astronautics at MIT and a specialist in software systems and safety. And she wrote because the software systems and safety on this went so well. I mean, this is this is sort of she there's a one of the sort of the primary sources for this is a extensive article paper that she basically wrote as a sort of complete breakdown of what went on Therac 25 is why we know so much about it. Because because a lot of the documentation that sort of otherwise might have happened,

just buried in things like lawsuits that were settled out of court. Wow. Sort of, you know, there was a net we'll get on to what happened with the FDA. But, you know, a lot of this was was documented by her quite extensively. So the appendix on the Therac 25 is published in software systems, safety and computers and quotes an AECL assurance manager stating that the Therac 6 package was used by the AECL software people when they started the Therac 25 software, the Therac 20 and Therac 25 programs were done independently

from a common base. One thing to remember here is the use of the word people. And that will come back to that. Just park that. That is that is Chekhov's people. Park that on the other side and come back to that. So next slide, please. Again, this is one way we probably need to do it in post.

We'll just we'll just we I'll send Dev the link to the thing and that. So we've got a thank you to thank you so much. So there is three main components to this and they rotate back and forth around the central axis. You've got a stainless steel mirror and a light assembly and this is it's a light. And that shows where the thing's going to show. So you get your patient into position. They lie down on the table laser beam looking thing and be like, you know,

aim this at the cancer. It's not even lasers. It's just a it's a you know, it's a you know, this is the 1980s. This is a sort of, you know, 100 watt, you know, 100 watt bulb on earth. We're going to aim this weak flashlight at the cancer. This this completely. You're a god damn it. Yeah, so that basically shines like the treatment area.

They sort of fiddle around with it and get it. So okay, when you know, get it in the middle of the field, get it so that the thing's going to be set up. You've got the new x-ray target, which is a conical piece of tungsten that's called a beam flattener and Leverson describes that as being an inverted ice cream cone. So yeah, that's what's in the earlier picture. It's sort of a conical bit of tungsten. So, you know, where the beam hits it sort of fills out through the through the

conical bit of tungsten and then what you get is a flat x-ray beam that kind of comes out with an even spread and then you can do stuff like put a sort of lead sort of trays on the patient to sort of further direct that. So, you know, you don't want to sort of irradiate a huge area. You can say, well, OK, we're doing a sort of skin thing, but we want to just kind of have the sort of eight centimeters where this thing is. And then the rest of is like a tungsten plate lead plate that goes over the top upturned baking tray with a hole punched out in the shape of your melanoma.

Yes, exactly. And then the electron mode, which is sort of surrounded by the scanning magnets, the wigglers, as we have referred. That was a delightful term that I sort of heard in a sort of doing the research for this on another video, they called these things wigglers. That's that's I'm so pleased that that's what they call them. Yeah. So they have then have what's called an ion chamber. So that measures the ionization levels in the air as the therapy beam or the x-rays

so that records the dosage that's delivered to the patient and then puts that dosage back on the terminal. And then as we talked about, we've got a counterweight and on the counterweight are three micro switches and they control the position of the therapy head. And so the position of the head can be set by the operator terminal or the use of a hand control. And this is one of the things on the 20 apparently that sort of operate. He's complained about sort of this thing is like, you know,

it's this is very heavy and we have to manually click this into place every time. No, so we've automated this process. Oh, good. Yes. So you have to like look down through this and like aim it first, aim with the mirror, then switch it to then switch it to the thing. And yeah, this, you know, we've got that sounds like a lot of work. We've got 20 something submarine periscope thing. Yeah. Yeah.

So wheel, you got a crank, you know? Yeah. Yeah. Exactly. Well, you actually have to run on and radiation medicine, Sisyphus, you know, and then there's a little piston here, which is which is like a locking device that kind of helps to lock the head in place once the thing's been selected. Next slide, please. So then the software components.

So this is the this is a simulation of the operating layout that the operator would see. It looks very Kvorkian. I like that. It's got very it's got very much. Macaulay, it's got matrix energy here. Yeah, bad ones. Yeah, matrix energy. I particularly enjoy treatment mode fix as opposed to break mode break. Yes.

Treatment mode make worse as a joke. Yeah. So the reason you'll see sort of dates on this that are sort of saying 20 something. Oh, this is this is running in an emulator. So people have been able to kind of reverse engineer and get hold of the code for this thing and then run it in a terminal emulator to see how it does. And then sort of to replicate sort of some of these things that that that might have gone wrong with it.

So nerds are amazing. So the things that are in the top line are the beam type. Where operators entered E for Electron. So this has got to attach a little keyboard E for Electron or X for X-ray. E. If you put in other letters, did it give you weird kinds of beams no one ever heard about? As far as my favorite phrase.

Having a Q-ray. Oh, God. Everyone around me has a pedophile. Yeah, you got shot with a Q-ray. Stop believing some really strange things about JFK Junior. So the the next sort of so that's actually the one thing just note on this screen. This is talking about killer killer electron volts.

We've already said this is a mega electron volt thing. And if you tell it to X-ray mode, this thing will just default to putting in 25 mega electron volts as the energy. It doesn't have any other options for X-rays. The second set of fields is the prescribed dose. So they go in and they say, I want this amount of radiation for this many RADs, this is all RADs. This is all using RADs because, you know, again,

this is ten years off the implementation of grays. But, you know, this is 200 RADs, two grays. Yeah, yeah, yeah. So that's how many RADs of radiation. And then you enter that the third set of fields is where the the gantry is. So that's the, you know, the position of the head and and then the bottom field, the date time, the operator ID, you know, this is Kevin doing the things today and tells the operator that the beam is ready to use.

All right, so you look at this, everything's as it should be. Entering all the information, you know, push, you know, perfect. So cancer over. So because we've sort of discussed the design of these of the setup this before, because you would need to protect your staff from the ionizing radiation, the terminal itself is located outside the therapy room. You can then got radiation shielding in the walls and a sealed door

between the treatment area and the control area. And there's usually a two way intercom system between the treatment area and the operating area. So the staff can say, you know, OK, you know, we're going to things thing. Now there's going to be a bit of noise, you know, if you've had an MRI or something like that, they kind of go, yeah, it's going to be noisy. And then it sort of sounds like the wheels are coming off every single tricycle in the world at once.

Yeah. And then you have a panic attack and they go, stop doing that. And you go, I can't. And they go, well, try harder. Continue until you do the thing where they sedate you, you know, I I had an MRI once and it was fine. You know, why? Because I knew I could easily get out of that hole if I had to. That's nice. Congratulations.

Fuck yeah, exactly. It's not a cave machine. Get up, sprint down a corridor and try and like open a sealed door, which is. Yeah. No, that's no match for Roz, of course. Yeah. I mean, it's simply built different. You are simply built different. We are probably another episode's worth of stuff in talking about MRI machines

and what's called missile effect. What a great name. Yeah, just directly sort of laser target my personal fears. Why don't you? Yes. This is the this is the, you know, why the MRI machines have the big lockable door and the and everything in there is plastic, everything in there is plastic. If there is a crash call, the separate sort of plastic things that they have to kind of grab because missile effect.

Yeah, the time they killed a kid in an MRI because he like went into cardiac arrest and there is someone brought in a metal oxygen tank that then got fired across the room, killing the patient. Yeah, it's awful. It's great. Yeah, this is it. It is absolutely, you know, that is the kind of it's happened that, you know, when I'm sort of doing my sort of radiation safety as part and imaging safety

as part of my course, that was kind of things like, you know, this, this is why this is metal, nothing, why nothing is metal here. Absolutely nothing is metal. If you have metal, leave the metal outside that just do not bring metal onto the unit, don't bring metal onto the floor, don't have metal. Metal not required in the MRI environment. Me talking to Spotify. Yes.

So during this sort of development system, test operators complain that sort of entering the data again on the terminal was too slow and ACL, I'm from Interim Function, whereby you could sort of copy the treatment site data by sort of process of a moral carry return. So, yep, yep, yep. OK, fine. You know, it just sort of copying it all over. And if the software detected an error would respond with one of two error states.

So either treatment suspend in which case it shuts the machine down and the whole thing would have to be restarted all over again. Oh, the annoying error. The annoying error. That's sort of by default. The thing that like incentivizes you to use or work around the other error form so that you don't have to do this. And then a treatment pause, which is where again, we're dealing with as we've

established dealing with a lot of sort of literalists at ACL. The treatment pause which could be overridden by the operator pressing the P key and up to five treatment pauses were allowed before the machine would require system restart error messages were generated alongside a number code. That's good. You get your number code and you can look up in the documentation as to 69. Error code 69 not implemented. The current one to 64.

Oh, well, yeah, lame. Yeah, fortunate. The supplied operators manual did not contain a descriptor of what the error messages were you don't need to know. Error code 13. What is it? Don't worry about it. Don't worry about it.

The maintenance manual did contain descriptions, but not whether they were of clinical risk to patients. Of course not. You don't need the maintenance people to know that. Yeah. So before like some real like 60s medical chauvinism of being like, well, it is not a doctor, is it? So whatever, to be honest.

Before sort of commercial distribution, they did a safety analysis of the device, but this was conducted on a hardware simulator under treatment conditions and they ran off sort of fault tree. But this only accounted for hardware failures and not software. And the assumptions that may be made that sort of levels and summarise but one is that sort of programming errors have been this is what they said. They said that programming errors have been reduced by extensive testing on

hardware simulator and under field conditions on teletherapy units. Any residual software errors are not included in the analysis. Program. So good. Program software does not degrade due to wear fatigue or reproduction process. Oh, OK. Sure. Yeah. Wasn't that like the first half of this presentation? Yeah. So.

Program's decay. Yeah, this is. So the sort of I originally sort of came on because I was like, hey, you know, there are some interesting medical failures that I'm aware of of engineering and then Alice sort of mentioned to me, oh, hey, we know, we've been looking to do the Therac 25 for a while. And I sort of went away and I looked at it and I went as a through line here because cancer is in itself a failure of essentially a meat coding.

And we are, you know, we can look here. We can we can draw an important parallel between that and a sort of a cancer treatment, which is hampered by an error in in sort of silicone software coding. So it's all it's all computers. It's all computers all the way down. Yeah, you cannot you cannot escape the computer. We are all going on the computer.

We have always been going on the computer. Yes. Yes. So the look into the box. Computer. The third point is that computer execution errors are caused by faulty hardware components and random soft random errors induced by alpha particles and electromagnetic noise at such a like my computer is the size of a fridge. Kind of conception of how computer errors happen is like this is a machine.

This is a machine on a human comprehensible scale. I don't need to think about circuit boards yet, really. There is like something has got into this cabinet and like made a connection wrong. So this is the sort of this random error thing. This is this is an alpha particle error. This is this is a this is a technique in speed running. Oh, yeah, of course, that happened, didn't it? Yes, this is a bit flip.

Yes, a bit flip. So that's that's basically if an error occurs in our software, it's because a solar a solar ray just happened to hit that bit of the. So did that. And it just did that just did that. Yeah, so the famous one is the 2013 Mario 64 speed run in which is which Dota teabag had a was sort of doing speed running things and had Mario suddenly walked to the upper floor of a level which sort of shaved

seconds off their time and allowed them to sort of do that, you know, do the sort of the best like an absurd cosmic error in your favor that like this one bit has been flipped by an outside force in such a way as to benefit. Yeah, it's sort of a new theory about JFK. Yeah, you got bitflips. You got bit the bit is a live modifier in the human head. So a total of 11 there are 25 devices were installed in hospitals throughout Canada and the USA.

And so we get to do a date. We finally get to Justin. No. Hi, it's Justin. So this is a commercial for the podcast that you're already listening to. People are annoyed by these. So let me get to the point. We have this thing called Patreon, right?

The deal is you give us two bucks a month and we give you an extra episode once a month. Sometimes it's a little inconsistent, but, you know, it's two bucks. You get what you pay for. And it also gets you our full back catalog of bonus episodes so you can learn about exciting topics like guns, pickup trucks or pickup trucks with guns on them. The money we raise through Patreon goes to making sure that the only ad you hear on this podcast is this one. Anyway, that's something to consider if you have two bucks to spare each month.

Join at patreon.com forward slash WTYP pod. Do it if you want or don't. It's your decision and we respect that. Back to the show. Oh, boy. June 3rd, 1985. So 61 year old banner here is Katie Yabra attended the Keniston Regional

oncology center in Georgia, Marietta, Georgia, for a 12 dose of radiotherapy treatment. She had had a previous surgical excision of a breast tumor and had follow up treatment with radiotherapy to local lymph nodes. Now, from where there is medical information, I've kind of jotted down sort of medical notes. And this is pretty standard for breast cancer treatment today, even so you can do, you know, a small enough sort of tumor, you can take a lump of breast tissue out. We we call this a wider local excision, but a lumpectomy is still a term that's often used and it's removed with a sort of normal tissue around it.

And then they send often a lymph node sample along with it and for the closest group of lymph nodes and in the armpit, usually, where we kind of look at one of those nodes and we look at it on the microscope and determine whether it's cancer. So if there is spread to local lymph nodes or if they suspect there might be, then these can still be treated either with radiotherapy or excision of the local lymph. And this is this is this is still pretty standard relative to modern practice. 1985 to now, things haven't changed that much. So she had breast cancer has been successfully treated.

She's now in for this follow up in the armpit. Yes. And she was prescribed a 10 mega electron volt electron therapy dose. So she goes in, the benzene's positioned. The operator exits the room, presses the on button. And then she describes feeling a tremendous force of heat, a red hot sensation and the technician. That's not it's not supposed to do that.

No, right. She's had this is her 12th dose of radiotherapy, 12th fraction of radiotherapy treatment. So she's had 11 previous ones and they've all been kind of fine. You know, she's gone in there. This patient was one day from retirement. Oh, no. So she's gone in there.

She's had the she's had the 11 days they've thought they've all been fine. And then she then suddenly, you know, that really, you know, really burned. The technician said, this is impossible. You know, she said, you know, she said, you burned me. And I said, that can't happen. The note was made. The treatment area did sort of feel warm to the touch. And then, you know, they went, oh, we're sorry about that.

And she was at home. And just had a treatment. You know, return. That's, you know, sorry, you know, fine. Over the next few days, however, the skin over the upper chest and the shoulder became painful, hot radiation exposure. It takes a minute. Yeah.

It takes a minute, you know, she was admitted to the hospital in Atlanta. But then so she's admitted to so she's in Marietta's or which I'm my geography of Atlanta is and of Georgia is not amazing. She was admitted to hospital in Atlanta. So the sort of the sort of secondary tertiary center continued to be sent to Kenison for further doses of radiotherapy. While she was inpatient with her radiation injury,

the pain sort of continues to increase. Her shoulder joint became immobile and the treating doctors thought this might be due to sort of treatment effect from the radiotherapy. So they just thought, OK, so she's had several doses of this. And we know that radiation has sort of stochastic effects. But then it's gone beyond that network that sort of the skin is breaking down.

And not only has she got sort of got this redness on the front of her shoulder, it's also on the back. Like you've been shot with a like a big like you've been shot with a relativistic, you know, beam of electrons. And Einstein gun. Yeah, so Einstein gunshot wound. So she was then seen by the medical physicist.

So this is a big shot. So whenever you have radiation emitting things in a hospital setting, not only do you have sort of technicians and on radio oncologists and people who sort of prescribe and deliver these sorts of doses, you also have to have a medical physicist. So a quite sort of person who's qualified at sort of radiation and knowing how the radiation is made to a sort of high to a sort of, you know, this is the person who knows all the theory of the radiation stuff.

So knows all the German words about what? Yes, it does seem like almost universally radiation is always like the last thing anyone thinks about about any particular injury. Yeah, so you have your sort of. I mean, let's not say they don't have a knowledge of the disease. I sort of say having done some sort of actually sort of level degree stuff that you have to have an idea of the sort of radiation safety, but these are the people who absolutely know their stuff

about medical sort of radiation physics and in their places in medical setting. So this guy, Tim Still is the Keneson physicist. And he's a sort of exactly the kind of obsessive nerd you need on staff to recognize radiation problems and then make meticulous notes about it. So it was obvious that this was a radiation injury. He reviewed her determined to receive one to two doses of radiation. In the 15 to 20,000 rad range to the effect.

Jesus, if we go if we go back, by the way, to the thing, more than 1000 rads is in the acute illness, early death. Yeah, like lethal dose 100 after 10 days. Castery, the highest one that we put up. Yes, the highest one. So because the kids in second, this is not a whole body radiation dose. This is just to a very small area. You know, effectively the width of an electron beam.

So about a millimeter. So you imagine these sort of 15,000, 20,000 rads being applied over about a millimeter wide area of tissue, basically. So. Tim Still contacted ACL to ask if the 35 could operate in electron mode without the beam scanning. And was told, of course, these, they're like, this is impossible. No, I'm sorry about that.

This was not reported to the FDA because they could not report it to the FDA. Because the FDA protocol at the time was that reports regarding medical devices could only be made by the medical device producers and importers and not by end users or patients. Beautiful. That is smart as shit. So if the Canadians don't want to do shit about it, something you can do.

Yeah. So unless the manufacturer wants to do something about a device and their position is, well, this is far safer than the previous device. Because of computer. Yes. This uses computers. This is this is safer. There is no way in which this could cause an incident. And fair play to Tim Still, because, you know, as we'll discover later,

this is kind of on the money here. No, this is the all the the medical physicists involved here were absolutely on the money and what was going wrong. And instantaneously diagnosed the problem. Not that anything's going to be done about it, but but so a second date. Oh, boy, you know, it's really good. July 26th, 1985.

So this and this is a 40 year old. This is so we're now we've gone north. We are now in the Ontario sent Ontario Cancer Federation Radiotherapy Facility in Hamilton, Ontario for a 24th treatment for cervical carcinoma. Again, cervical carcinoma is something that is kind of treated with radiation in the sort of early or locally advanced stages.

One of these things whereby if you've got sort of the risk of recurrence after surgery, or if someone's got inoperable tumor, but that's one that's bleeding, then you can do palliative treatment with with radiotherapy, sort of basically sclerose the tumor and stop it from bleeding and give someone, you know, while you're not going to cure their cancer, you mean, you know, they're not sort of getting lots of sort of vaginal bleeding or something like that that's uncomfortable and trying to give people some some element

of dignity, even though they're in the sort of final phase of the cancer. And this is either done by radiotherapy, sort of external radiotherapy like this, or you can implant radioactive pallets that sort of emit radiation locally. So it's called brachytherapy. So on this occasion, the patient was receiving therapy. They were positioned for treatment. The technician set the device up for therapy.

It was initiated and the machine shut down after five seconds, reporting a H tilt error and the terminal screened sort of a sort of a pinball machine thing. Yeah, so it's tell, you know, you made it mad. Yeah, you have an idea of like how long a typical like exposure is like supposed to be just to contextualize that. Just a ballpark either like seconds, minutes. It's it's it's kind of seconds, really. You know, some of these, you know, some of the sort of the more sort of scanning

action being may take a sort of minute, but this is far. This is pretty quick. You know, an x-ray exposure is like, you know, people have had sort of diagnostic x-rays, that's a, you know, couple of, you know, quick second, you know, that's that's the that's the field. So it's a joke. I remember about chiropractic, which is like, you know, medical doctors like, well, you know, we'll do some tests and, you know,

we'll try some things and if it doesn't work, then we'll know some more things. Whereas a chiropractor is sort of like sprinting towards you, like setting up for a football kick, like say goodbye to back pain. Sort of like this, but with cancer is like sprinting towards the beam. Just like, right. So the terminal screen, right? The real joke is is chiropractic. Oh, yeah.

Learned, learned how to do it from a ghost. Yeah. Yeah. I mean, as someone that's that's formally done some training orthopedics, I have seen a non-zero number of chiropractic injuries. Anyway, I don't want to get sort of sued by a ghost, so I'll not say any more. So the terminal screen displayed a no-dose

and indicated that there was a treatment pause. So the operator presses the P key. Again, another no-dose error. And most operators at this point, this this was a finicky piece of kit. They were, you know, they put the patient in the thing. They have to go all the way out of the room. And then they press the button to go and it goes, no.

And now I sort of go back into the room and I check it. I come out and I press P again. Oh, OK. So this was not an infrequent occurrence. And on this occasion, the operator pressed the P key a further three times. This is triggering the magic five, five times they've had to press the P key. Yes, sticky keys.

Yeah, yeah, it's now. So sticky keys is now enabled and the machine enters treatment to spend. So it shuts down and then the hospital and then you have to sort of call the technician and technician goes, what have you done? I can't. You know, they had to sort of basically, you know, come and do everything back up again. And this is a turn it off at the wall.

Turn it back on again. The wall, turn it back on again. You know, wait for the tape drive to spin off, etc. And then sort of shortly after treatment, the patient complained of burning and tingling pain in the treatment area. They returned for further treatment three days later. By this point, they were then reporting severe pain, swelling and redness and then were hospitalized to the following day.

Radiation injuries, you feel kind of weird, then you feel really real bad. So the machine was taken out of service and the ACL was again informed of a potential radiation injury. They sent an engineer to investigate the machine. And as the manufacturer was now involved in the proceedings, the Canadian Radiation Protection Board was informed of the incident and the FDA was sort of starting to be made aware of this. And the Canadian Radiation Protection Board issued a notice that users

have to manually confirm the treatment head position. But it didn't state anywhere there's been any patient harm. So the patient who received an excess of dose in this scenario, unfortunately, to come to her cancer a few months later. It was it was a terminal case coming in. Yeah, this is the sort of case I was talking about where someone's sort of having palliative radiotherapy for a cancer that's that's you know, it's not curable, but we're trying to sort of make your last days reasonably comfortable.

Sure, which wasn't the case here because we've actually made them much more uncomfortable. Yes, the degree of radiation so this person had an autopsy and it was reported that had she not died as a result of the cancer, the degree of radiation injuries sustained would have necessitated a hip replacement procedure to restore mobility to the joint. Just like melted part of your pelvis. Yeah, yeah, you got the effect of like sort of like when you open a fridge door with like with your hips, but it's the door to like the containment room at Chernobyl.

Yeah. Yes. Yeah. So the estimated dose here was in the region of 13,000 to 17,000 grads. Not very good. No, no. So ACL carried out an investigation incident and failed to reproduce the circumstances. They did, however, identify mechanical issues relating to the plunger locket mechanism and the micro switch array. And what they sort of ACL's investigation, they were purely looking at hardware.

Because again, this is software can't go wrong. Yeah, software. It only goes wrong. We've tested it. It only goes wrong when like you idiot or whatever, get into the case. And they kind of what what they sort of assess was that sort of this is you've got a three bit micro situation so each of your micro switches can be in

the sort of zero or one position. So what they modified the software to do was tolerate a one bit error. So that. Effectively, you've got three, three bits there. So if two of them are in the correct position, it's OK. It's an introduced now immune to like the running sort of error. Yeah, but but it's got an additional sort of track, the fact that it's in move, it's in motion.

They issued a voluntary recall notice at this point. And this was a car, what's called a class two recall from the FDA, which is described. This, you know, just making sure I go with it. So the other thing is a situation in which the use or exposure to a violative product may cause temporary or medically reversible adverse health consequences or where the probability of serious adverse health consequences is remote. So it would be nice to fix it as opposed to your one violation, which it which is fix it sort of.

I assume this is not a situation where they physically recall the machines because that sounds very difficult. They sent they were basically sort of sent engineers out to sort of go and you know, this is the 80s, you've got to go and redo the code by kind of the hand that there's only 11 sites where this is installed. So you've got to do it 11 times. You've got to sort of send some guys off for a week to recode things. Basically, and they they they audited the changes internally and end users were

told they could resume use once necessary modifications have been made. And they touted this as a safety improvement of five orders of magnitude over the previous system. Sounds good. Yes, good. Num, num, num, number big. How do you how do you measure that? So, so there is a towards the end of the leveson document.

And please allow me to scroll through. Here we go. The evidence for the belief that radiation burn could not have been caused by the machine included a probabilistic risk assessment showing the safety had increased by five orders of magnitude as a result of the micro switch fix. Meanwhile, your medical physicist is there just like, and yes, but how did they get the radiation burns? Yes, into glue, right?

Just like presumably being like a very, very localized cosmic gamma ray burst. It comes in through a window or something, you know, while they're in the wasting room. So the belief that safety this is from leveson, perhaps it was based on the probability failure of the micro switch, which is typically 10 to the power of minus five and it with the other interlocks. OK, yeah, all right, sure. So so one micro switch only fails sort of, you know, 10 to the minus five times. And then they've gone, well, we've got three of these.

And it makes sense. Yeah. So five. That's it. Faultless. Yeah. We've we know we've we've made it sort of so that there's a bit of error. That's five times safer. All right. Case closed. No more next slide, please. Look at a nice older gentleman, a nice older gentleman.

This is this is Gordon Gord Simmons, who passed away in May of last year. And in nineteen RIP, it's trying to this is the thing with this device is like sort of trying to this thing was so, you know, people know about it because it's kind of got notoriety, it's kind of go online to be able to talk about it various times. But actually sort of trying to find sort of contemporary pictures or anything of anyone involved. So this this, as far as I can tell, is the same guy. It's sort of found from a local newspaper article from May of this year.

You have to be named Gord. I will say that you do another sort of medical medicine of another sort of physicist. And this guy is the head of advanced x-ray systems at the Canadian RPB. And he was tasked with investigating the July 26th in Hamilton. He concluded, in addition to the faulty microswitch design, there were four other areas that needed to be addressed in order

for the threat 25 to pass the Canadian certification for radiation emitting devices. Most significant of these was that there was to be a dose error detected. The machine would move immediately to treatment to spend rather than treatment. Pause. So you only have to press the P key and you can hit them with the wrong dose. Yeah. So what this guy was saying is that it shouldn't let you do that. Basically, if there's an error, if there's an error, if anything goes wrong, it should suspend treatment, which this seems sensible.

You don't have to get up and walk around the thing off and turn the thing off. Yes. And call the technician. And then, yeah. I have to make a phone call just because I was about to give someone radiation poisoning. AECL did respond to the error to this, to this edit from the Canadian RPB. And their response was to alter the number of times the treatment could be could be overridden from five times to three times.

Beautiful. Well, you can only get three lethal doses. And then compromises, compromises how we get things done. I mean, that's right. So. They had made changes to the micro switches and all of the devices. However, the other recommendations, including alterations to the sort of testing of the beam and the error reporting, which Simmons had told AECL would need to be in place to actually receive the

Canadian certification, were still pending when another incident occurred in December of 1985. Oh, no. Worth noting that just before we move on and Justin gets to do another date, that the team at Hamilton were not happy with AECL's response. And they requested that AECL install that sort of tensioning system and a mechanical interlock on the treatment head. AECL refused.

Again, medical physicists went, no, we're doing it anyway and installed it themselves. Avoid the warranty of your voice, the warranty and wearing it. I wear I avoid warranties t-shirt under my scrubs as I bang it. This extremely extensive machine with a hammer. Yeah, just like you actually to jailbreak my linear accelerator. Me and John Deere farmers, you know how it is. Yes, right to repair ice cream.

Stop me if I'm getting ahead of us. But am I correct in thinking the previous version of this device had mechanical interlocks? The previous version of the device had mechanical interlocks. You don't need a braze, they had weight. Oh, yeah, because this one's software controlled. So the previous one had hardware interlocks. One thing that people did note, which will be relevant later, is that the previous version did have a tendency to sort of blow fuses and things like it would, you know,

it was again, the reason that what some of the operators sort of used to this the software on this being vinegar is that they'd worked with the previous versions of the device and this was like, OK, it's shut down. It would suspend it. Have to hit the peak he loads of times and sometimes a fuse would blow and the machine would be out of commission. So I'll have to come replace the fuses, etc. Sure. Yeah.

Yeah. Anyway. Though, you know, these were operated. These, you know, these were user end errors, of course. So if anything happened like that, that didn't go anywhere. There's certainly not the FDA because because it wasn't a manufacturer report. So the third incident, next slide. December 1985. Yeah, we don't this is very, very sketchy the information here.

But what we do know is that following the this is a Yakima Valley Memorial Hospital in Washington. Yakima Yakima. The last come from there. That's what I know. The patient had a there's on their first cycle of therapy and they had red is the skin around the hip area with a sort of unusual pattern of injury resembling strikes, stripes, rather, the staff who examined the patient were concerned.

This pattern matched the I've mentioned this before. These are all blocking trays. So, you know, we just sort of leds oven tray with a circle cut out of it. They sort of were concerned that the pattern matched the the blocking trays that they had. However, because they took the trays and after they've received so much radiation dose, they become a radiation hazard, so they have to throw the trays away. They couldn't they couldn't match it.

And kind of so it's like the radiation dose is like so strong that it has like burned the outline of the the tray. Yeah, but the sort of the sort of the sort of treating doctors also said, well, it could have been caused by a electrical thermal pad or blanket. The patient is someone who's got sort of they got cancer and they've got sort of, you know, it's a key and they put a heat blanket on it. They put an electric blanket on it to warm up and they sort of say, yeah, it's possible that we fucked up.

But on the other hand, it's also possible the patient's an idiot. Yeah, yeah, or the electric blanket fucked up or something like that. You know, we don't, you know, we don't know. Yeah, never mind. I has the medical equivalent of driving a dick into some friend's skin. So the staff contacted the ACL and ACL were told there was in no way in which the device or operator could have result in injury. And again, this device had undergone the required changes to the

microscope array and had a five order of magnitude improvement in safety. So it's fine. It's fine. Clearly, it's nothing. So this this this had this device had been upgraded in September of 1985. And I've been operating for two, three months at this point without incident. The doctors described the rash to causes unknown, but the sort of, you know, what we know of the long term of this is about two years later, as the sort of discovery process was sort of going on here, that the patient had

gone to suffer extensive skin and soft tissue injury, non-healing ulceration requiring skin grafts, basically to repair the skin damage. Yes. OK. And instant number four. Oh, this is this is the real bad one. This is this is this is the this is the real bad one.

So, you know, like the radiation sort of nightmare story. Yeah. So, you know, you know, if everyone hadn't sort of checked out at this point, this is, you know, content warning, content warning, content warning, medical radiation injury. March 21st, 1986. So, Voyn Ray Cox, a 40 year old gentleman that tends the East Texas Cancer Center in Tyler, Texas

for post-surgery radiotherapy for a tumor on the back. It doesn't mention what the tumor is. This is the, you know, we use it for melanoma. We use it as sort of larger squamous cell carcinomas, that sort of melanoma. Obviously, you know, anisites, squamous cells or the sort of cells in the skin. But we tend to treat those with surgery. So this is, you know, might have been something like a melanoma. We don't know.

The patient was prescribed a dose of a 22 mega electron volt electron beam therapy to the left, upper, back, and the. The patient at that point was in deliver a total fraction of 180 rats with repeat doses over the next several weeks, totaling 6,000 rats. So we've already talked about 6,000 rats, you know, in one go. So your whole body, very bad, very bad, very bad, 6,000. Whereas if you do spread out on the sort of like, you know, eight radiotherapy

fractions and your ninth one is free, sort of like, yeah, the stamp thing. It's not as bad. Yeah, exactly. So. He was sort of this was his ninth cycle. So again, like this sort of verse, like the first and this is on who knows what to expect, they go into the room, they get sort of position, they sort of lie down or sit up or sort of get into the place where they need to be to sort of have the

therapy, the beams sort of all set up and then off they go. So. Again. The operator here is behind a heavy shielded door down the corridor. There are no windows between the treatment and the operator suite and the means of monitoring is a video camera. So sort of 1980s scan line quality internal video and an intercom system. However.

Sorry. However, on this occasion, the intercom system had broken. Oh, great. Sort of like final destination. Yes. Yeah. So patient was positioned, the operator exited, closed the shielded door between the treatment suite and the control room, entered the prescription data

on the terminal on reviewing, noted she'd inadvertently typed X for X-ray mode. So she promptly skipped back up to the modality field. You know, we had our little screen earlier and changed it to E for electron beam. Everything else was correct. Hit the key to proceed. Should have changed to G for good. Yeah. No, no, that's the one that changes your gender.

Oh, no. Don't they don't allow that the UK fucking. The G writes hit by the gender beam for civilization. So on this occasion, the machine entered a treatment pause and return the words. Remember, the operator has no has the operator manual has no description of the errors. Return the words malfunctioned 54. Hmm. Great. OK.

Could be anything. The dosage report on the machine, however, says a substantial underdose of radiation. That's what was prescribed. Oh, good. And why it's always a good idea to have an OBD to a reader with you when you're doing it, I brought this guy your counter from home and I'm holding it in between me and the fucking thing.

It just flashes the check engine light. Flash the third ECU tuning the Therac. I want the pops and bangs mod for my Therac 25. So, you know, this this machine as we said, this is a finicky machine. This does this all the time and it paused it and she pressed the P key to override the pause and proceed with the dose as prescribed. And the machine malfunctioned 54. Oh, go press P again.

Well, you would press it was going to press P again, but then was alarmed by the sound of the audibly upset, disturbed patient banging on the operator room door. Oh, fuck. Hmm, not good, not good. Shit, you. Yeah, that's not what you want. Next slide, I think.

Yes, so we're this again, we'll just go back to our set up here to remind ourselves of the situation here. So we've got operator terminal sealed away. Intercom that's not working. Patient has come off of the treatment table. And as they're coming off the treatment table, the operator presses P again. You got hit with a fucking like glancing blow by this thing as well. Yes.

This is why it wouldn't be me, right? You put me in a situation like that. I'm like, they find me melted a puddle of goo because she's done it five times. And I've been like, why don't I want to be an author? I'm not going to sit up. She did say to sit still. So yeah, this guy clearly has just like flown out of the thing. Yeah.

So this is so he knows that this is not normal. But basically, he sort of felt what he reported as a severe pain like someone had poured hot coffee on his back when the operator engaged the device for the first time and it was rising from the table to alert her when the second dose was delivered, describing severe pain in his arm and a sensation like his hand was leaving his body. What the fuck? Jesus Christ.

So he just stood up, he had his arm in the way of it, and we just accidentally sent this man's hands, atoms to fucking Jupiter. It's like fucking orbiting the rings of Saturn. And he's just like, OK, just still attached to it, you know. So the patient was seen by the medical team on site who sort of noted reddening in the treatment area as he wasn't unwell in himself was discharged home. Because the minute, you know, yeah, because they say, well, you know, this is this is, you know, this is a safe, established device we've used for years.

This is the must have been a freak sort of electrical shock. However, like from like a from like a Tesla coil that's been embedded in the machine, like, where is this electricity coming from? Again, I mean, I think sort of part of the thing is here is that, you know, we with documentation is limited. But I think sort of from a point of view of someone who has sort of been trained at medical school, never been sort of trained, you know, although sort of, you know, having some

additional experience in radiation bits and pieces, but you don't expect to see a radiation injury. What was far more, you know, what you think is was an electrical device. Electric shocks far more common. And what they've reported sounds like an electric shock. But, you know, their cardiac function is OK. They've not got an arrhythmia. And, you know, the treatment sort of severe electric, you know, severe, you know,

electric shock, so there's no arrhythmia. Then, you know, the patient's otherwise well, then they sort of then they can be discharged type. We know they were just in a radiation machine, but yeah, probably wasn't a radiation injury. Right, guys, because this is a radiation. This is a radiation machine that's very safe. The previous versions of it were very safe.

The manufacturer has just upgraded this machine six months earlier and it is now five fold safer than it was before the upgrade. That's just five fold, five orders of magnitude. So five orders of magnitude safer than before the upgrade. So so it's the kind of thing whereby it's sort of, you know, you know, in men's was all to talk about sort of like, you know, if you see sort of hoof print, sort of expect horses, not zebras kind of thing. I suspect that, you know, it's very difficult to speculate on a sort of

at this point, sort of 40 year old medical case with for which I don't have any notes. But that's very little that they could have done. Like, had had they immediately been able to go, this guy suffered a catastrophic radiation injury, I mean, the thing you do at that point is you fucking roll your chair over to the draw on hand in one of those. So you're going to die pamphlets. Yeah, give the guy a cigarette. Manufacturer claims this device will have one accident in the lifetime of the

observable universe. And this was it so we can all relax, you know. So tragically, over the next several months, the patient lost use of the left arm and several bouts of nausea, vomiting, developed radiation induced myelitis. Myelitis is nerve inflammation in the spinal cord and his left arm became paralyzed entirely as did his vocal cords. This I mean, this is this is just horrific.

In addition, he was severely immunocompromised. So sort of, you know, and then sort of had opportunistic herpes virus infections of skin in the affected areas, lost bladder and bowel control and died five months afterwards with what was later estimated to be a dose of between sixteen and a half thousand and twenty five thousand rads having been delivered. Presumably not knowing why as well. Like that that also sort of rankles with me is the idea that not only did you

like kill the guy horribly, but you killed the guy in a sort of a horrible, confusing way. It's awful. I mean, as I this is this, you know, but it's sort of combined with the sort of horror of the, you know, you know, intercom being sort of out. This is the real sort of, you know, this is the nightmare scenario for any sort of medical treatment gone wrong, really.

Yeah, if you're if you're a radiologist or, you know, in that field, it's all like hearing the guy so bang on the inside of the door. That's the worst thing that you can imagine happening. I say from what it sounds like this, this, this it's not recorded who the operator was. And I think the sort of purposes of, you know, is that their anonymity has been maintained and given. So yeah, good.

Given the role they have to sort of play later in sort of, which is kind of fairly crucial that I think it's quite, you know, they they were doing their job as they were routinely expect, you know, routinely expect to do their job. They were working with the machine within the parameters they've been told to operate the machine. And that, you know, for both from a patient and a clinician perspective, this is absolutely the sort of the worst case scenario that could ever happen

in medicine because, you know, you know, you know, it's sort of there is, you know, varying to degrees to which sort of there is a sort of Hippocratic oath as such. But first, you know, how does, you know, it's a greater, you know, to a greater extent remains the, you know, the foundational principle of medicine? In the case of the Thera 25 device here, this was used to successfully treat other patients later that day.

Ah, yeah. Again, but taken out of service the following day for testing, they flew a ACL engineer down from Canada to try and reproduce the malfunction 54 error. Did we ever find out what the malfunction 54 malfunction 54 is very helpful? It tells the operator that the patient has either received too little or too much radiation. Oh, great.

Thanks. OK, I don't really know what's down. I got I was about to say, I mean, but that that that eliminates one number. Yeah, it reminds me that, you know, a lot of NASA software had to develop like different states for off scale high versus off scale low, because if you just say, this is not a reportable, like this is not a number, I can return for this query, it leads you to this sort of ambiguity. Yeah.

So ACL basically still at this point, flatly denied it's impossible. It was possible for the device to overdose the patient. The electrical systems were checked was still for the function on this is an electrical system error, but the machine would determine to be properly grounded and that could not have delivered an electrical shock to the patient. And the machine was returned to service a few weeks later on the 7th of April, 1986.

I mean, it's still it's still busily, you know, tracing cancers. Yeah, it's still treating cancer. You know, but successfully. So, yeah, yeah, the guy didn't die of cancer. Yeah, he just got a Chernobyl drop on his face, but it's hard. Yes. However. April 11th, 1986.

So four days after the device has been returned to service, another patient, Vernon Kidd, attended for cancer treatment on the face. We have very limited other clinical information. The same operator that had treated the previous patient set up the machine for therapy. Great. What's the worst part of your body? You can imagine getting this malfunctioning thing fired at. No, it's face, it's face, face or tail, whatever. So again, these are the all this is one of the more extensively documented

instance, sort of for better in terms of this helps sort of uncover what was going on, but worse in terms of again, a heavy content warning for a medically sustained radiation injury. The same offer is the same operators previously as well. Having sort of set this patient up for treatment. The intercom had been fixed. There's one. OK, OK, OK, it was like, yeah,

saving, saving sort of grace of the system, the intercom had been fixed. And as it ended previously, she entered X for X-ray before proceeding to treat. Notice her inputs went back, corrected this to E for electron beam mode. Commence the treatment. Over the now repaired intercom. She heard a. Loud noise from the machine with the terminal once again displaying malfunctioned 54.

Also audible, the sounds of a distressed patient moaning for help. The operator entered the room helps. This this is on the face, so sort of you get the person in position and then you have to for sort of a lot of therapeutic and diagnostic procedures sometimes need to keep people in position. So sometimes you have to sort of take maybe sort of, you know, lightly take people like bondage. Yeah, yeah, yeah,

for for for medical reasons for hours for medical reasons. I'm sorry if that appeared prurient of me. Yeah. He complained feeling fire on the side of his face and the medical physicist attended the fire play this. But so the so the sort of the having had the sort of ongoing investigation for the last several weeks, the medical physicist was very interested in seeing what has gone on here

and got a statement from the patient. And the statement was that he saw an intense flash of light. Oh, it's bad. No, you don't want to see that. Look at the pretty blue. What is it? Look at the pretty blue trial and on the pretty blue light. Yes. Yeah.

Describing the sound like that of frying eggs. Oh, Leveson, Nancy Leveson was sort of has further documentation on this. And she reports in her appendix that you repeatedly was asking what happened to me and was extremely distressed. Yeah, I bet Jesus. Yeah, yeah. Unfortunately, what happened to him was radiation and

catholopathy with Jesus, including so became increasingly delirious and confused. Entering a coma because, you know, they were on to something is wrong with this machine. They had an autopsy performed demonstrating acute high dose radiation injury to the temporal lobe and this gentleman, Vernon Kidd, has the dubious honor of being the first person documented to have died due to therapeutic radiation therapy. Wow. I mean,

horribly, yeah, pretty bad. So the so as we mentioned, this is this is another medical physicist. Next slide, please. This is the trip. There is a certain sort of story as people get wildly drunk in my home. This is if you can hear that at home, viewers, but that you might be able to. I can hear it.

Yeah, I don't know about it. So this time this is the Tyler East medical center, the Tyler East Cancer Center's Fritz Harga, who sort of again, I've tried to find sort of pictures of people and I searched Fritz Harga in Tyler, Texas and returned a picture of this young gentleman who is American Idol's top five contestant, Fritz Harga, the third. So grandson question, grandson, question, question, question mark as unless there is an abundance of Fritz Harga's in Tyler, Texas and specifically Tyler, Texas.

That's a German in Texas. And some checks, some potentially some relation as far as I can establish, you know, I'm going to be picturing the guy, the radiation. Yeah, I mean, given the amount of documentation that this guy did into the into what went on with with this, this is the sort of kind of largely responsible for documenting what one of the major flaws of the system was. And he and the operator who'd been involved in both cases pulled, you know, it's not specifically sort of said in the documentation,

but you get the impression that sort of all nighters were pulled trying to replicate the error. Right, yeah, I have a small, perhaps nonsensical thing, which is I hope it was the operator's unwitting fault because that seems less cruel than it being random chance both times. The key thing here is that this is a very experienced operator. So they have so they have been using the the Therac 25 and presumably possibly previous versions of the machine or other similar machines, so they were very, very quick.

I mean, sort of imagine someone who's using the system day in, day out to treat 20 patients per day, 100 patients in a week. You know, your hours on the machine build up to the fact that you can, you can, you know, you rapidly edit stuff and you go, oh, OK, I find out, you know, how many times a day do you sort of accidentally typo something? Oh, yeah, this is this is an electron beam. This is this is this isn't actually this is electron beam. You know, quickly correct the error, off we go.

So this was so they recreated the error basically by achieving this by rapidly editing, editing the extra in modality to electron beam in the dose set up screen. And because they were so quick at entering and making the corrections, they could both the operator and the physicist could reproduce the error at will. The ACL, it's a timing problem. It's a timing problem. So the ACL engineer the following day was unable to reproduce the error. He's like hunting and pecking on the keyboard.

Yeah. So as Levison says, the ETCC physicists explain the procedure had to be performed quite rapidly. Eventually, they someone, ACL, found a fast enough typist to reproduce the error on test machine. Were engineers reported a center of field dose of around 25,000 rats. Two hundred and fifty grays. The frying sound was determined to be so a while ago now, we mentioned that the. Each of the treatment heads has a

an ion chamber, which is called the dose at the exit point. And these were completely saturated. So it's fuck the frying sound, you know, the frying sound at least for sort of some respite for the frying sound was not patient related. No, the burning dosimeter. Yeah, burning. The completely saturated ion chambers, the every single ion in them

saturated with a lot of radiation in litigation. The ion detector just returns. Yes. Whoops. Yes. Yes. Ion present. This just says liable. So in one of the cases, and I think it was the the previous incident number four, there was already a litigation arising from that. And ACL representatives admitted they had been aware

of the cursor problem in other centers over a year earlier after previous incidents, but thought software issues have been fixed. How many previous incidents aren't there here? Yes. And that's the thing. You know, this this is a device that's going to be used every day. We, you know, there are six incidents that we're aware of. We are, I mean, it's hard to hide radiation

injuries, but on the other hand, with people who are very sick already. Yeah. I mean, that's one of the things as well, I think, and found some of the issues that, you know, people who are very, very sick already with with cancer. But some of these people, I think, and then the issues where this is kind of picked up are where people kind of had cancers that were, you know, maybe less severe or, you know, but then had horrific consequences from their therapy. So we mentioned that the FDA had sort of been involved at this point.

At this point, the FDA really gets involved. So these two incidents in rapid succession, reported by the Texas Health Department to the FDA anyway, despite, you know, despite the fact that there's no not a reporting mechanism. They sort of just kept calling the FDA until, you know, they sort of created one. Someone answered them. Yes.

So. ACL's initial response. That they made three days after the second instant was that all current device users were to refrain from using the up arrow to edit treatment. OK, all right, I like this. I like this BSDS solution even better so that no one accidentally presses the up arrow, the up arrow was required to be removed from the terminal.

Yes, now we're getting serious about access control. If you don't want people to use the button, take the button off the machine and lock it in a cupboard somewhere. Take the button off the keyboard, take the key micro switch over so it's in the open position and that's only able to re-enter the prescription information from scratch in the case of an error. Beautiful. So so far in terms of the corrective actions issued by thing, we've we've we've

sort of, you know, messed around with the micro switches and we've got a screwdriver to lever the key off the keyboard. This is what a how many million dollar machine here? I don't know what the one thing I didn't look at was how much this thing cost. I probably should have done that. But, you know, I lots, lots of money. States of the art piece of medical equipment. States of the art computer controlled.

Hold on, hold on, I got it. But prices rate rules. What do you got? Two million dollars. We playing a replay with inflation without without half a million. I'm going to go 750,000. Yeah. Dr.

Tom's got it. It's a million. Oh, I want to buy. I don't know how much these things cost. But it quite literally a million dollars. Damn it, dude. So the FDA were unsatisfied with this response. And everyone's a critic. Declare the declare the tariff 25 defective on May 2nd,

1986, requiring that the ACL produce a corrective action plan. And then shortly after this, there is we enter because this is May. And then sort of in medicine, then sort of June through August, before the sort of new term of this is sort of, you know, when there's sort of. Term of medical school kind of tends to kick out and sort of medical training tends to sort of kick out and before the new input sort of comes in October. This is conference season. Ah, yes.

Well, lots to talk about. Yes. So this has been installed at 11 sites and a users group convenes at the American Association of Physicists in medicine. So to ask some questions like why does this kill my patients? Yes. So so this is that, you know, this is where your our previous Tim Still from Hamilton

and Fritz Hager and other operators could all talk to each other about the ways in which the their act 25 seems to be going wrong. And the safety modifications they've been forced to make such as retrofitting their own safety hardware interlock and believe the attending ACL representative. Oh, that's that guy's going to have an interesting time at that conference. Yeah. Being being sort of put the question, why has my colleague had sort of one of the worst experiences you can have as

a medical professional and inadvertently killed a patient horribly due to your company's product for how would you like to be paid? Yeah, I mean, I think one million dollars. Alice is going to be somewhat familiar with this, but there is there is a way of documenting things in medical legal note keeping. The question was was asked in a sort of a robust tone. You know, I put it to him that he had, you know, assisted in the murder of my patients. So they there were this is this is sort of meeting notes that were recorded

and recounted in Levison's appendix, which was. There was a general complaint by all users about the lack of information propagation. The users were not happy about receiving incomplete information. The ACL representative countered by stating that ACL does not wish to spread rumors and that the ACL has no policy to quote, keep things quiet. Unquote. You sound like you don't, but yeah. The consensus among the users is that improvement is necessary.

Yeah, I bet. So we were a sense of that consensus. Millimetres from an outright brawl here is what I'm getting. Yeah, with the chair. Get him with the chair. So not only sort of content with bullying the ACL representative in person, they put together a zine. Oh, well, what's the ACS, you know, just anyone could do it.

So there were two issues of the user. Threat 25 user group zine, the first of which in the outline, the first of which contained commentary by Tim Still, the physicist at Kenniston, where the first incident occurred, outlining eight significant issues he felt were present in the Threat 25 software systems. Second issue expanded on just one of those are function relating to the head position micro switches further and the problems that potentially arose.

Again, I would love to find this. I again, this is something that is almost certainly lost to time because there are this was it, you know, this was 11 centres. Mimeographed. Yeah, sort of 11 centres of which sort of half the half the people involved are sort of probably dead. And, you know, this is this, you know, there may be a copy in someone's attic somewhere. But, you know, if we ever see it, that would be amazing.

But not in the scope of this recording. Next slide, please. What actually went wrong with software? So. The Threat 25 software was developed using the Threat 6 and the Threat 20 operating software as a base, entirely proprietary system, creating an assembly language of the PDP 11. And as far as it can be established, remember, we parked the phrase people.

Yes, as far as can be established was written by a single anonymous programmer. Person, person is something for the software person. This is the software person. Yes, in assembly, in assembly. So is Chris Sawyer. Yes, Chris Sawyer. Programming was different back in those days. You could do the sort of the Margaret Hamilton thing of, you know, Chris Sawyer programmed all of the, you know, all 11,000 lines of code necessary

to horribly kill a patient by hand. So when the initial X is entered, the software starts setting up the electron gun in readiness to deliver the, we've mentioned this before, this, when you put in the X, it defaults to 25 mega electron volts of X-ray. Photons. Yeah, and then it has to rotate the like head of the machine into the. Yes, position for X-ray. Yeah, and also set up the magnets inside to bend the beam around to hit the target.

During the magnet setup process, the software clears all of the internal data several times. So if you make changes to the prescribed treatment modality within that approximately eight second window. It displays the corrected prescription information on the operator screen. However, the software has configured the magnets within the linear accelerator to produce a particle accelerator beam at the intensity intended for X-ray generation, not electron beam therapy. Like that.

So. They dug out the software for the Therac 6 and the Therac 20 and it couldn't produce the same error, but because of the hardware interlocks, then the didn't didn't have any incidents because the beam didn't fire or a fuse would blow. This is like not a like not something that comes up until you make it purely software and then it's firing like an electron beam at the intensity required for an X-ray beam, which is going to draw off 99 percent of that power anyway. Yes.

But it's not sure. Yes, it's not doing that. It's firing it through the electron window. I was surprised it didn't just straight up explode. It's a testament to particle accelerators, right? As a science that like, hey, you can make one of these, it'll do it. You know, no problems.

The machine works fine. Yeah, good to inform you that I have to drop off at this point. It being eight o'clock. Sorry, Lynn. OK, no worries. Yeah, just I'll just keep the window open. Yeah, OK. Tommy, you get on time or do you want to like take?

Do you want to like record this in two parts? What do you feel like? If you're flying, I don't want to keep you. I mean, I've got I've not got many more pages left of my spiel here. We're kind of in the high stretch. So we got we got seven more slides and then we got safety third, which we can skip and yeah, yeah. Have a good night, everybody. Thank you.

All right, good night. Thank you, Lynn. So. The investigators noted that basically the speed at which the experience offered to make the changes, the prescription information. Could that's eight seconds? Yeah, this is an up key and an E keys. Not that much.

No, and it's but it's sort of, you know, they've got to skip through all of the previous lines up to the thing. And this is someone who's very, very experienced and because you'd be like, click back down to the bottom line, go. Oh. So they basically said the speed at which they can operate meant that you could make the changes within that eight second window. But also because they're so quick at operating this, it's kind of, you know,

the faster you type, the more errors you may introduce. So and and because the system is so finicky, they're used to operating with a thing that's going, it's it's paused again. This feels like one of those cultural things where it's like, I remember reading something about it was like a it was a fighter pilot's memoir from the Second World War, but his his friend is like a not he can't quite get to grips with the idea

of like dog fighting. His brain doesn't work that way. Well, he's good at his like flying very straight and level, despite distractions. And what they're actually telling us, you know, go and go and be a bomber pilot, go and do that instead, which he's very successful. And it's like it feels like this is one of those applications where what you want is sort of like extreme consistency and like thoughtfulness rather than like speed of action. But if you've got, you know, 20 patients to see that day, then it doesn't,

you know, there's different sets of incentives. Yes. You know, exactly. This is, I mean, very relevant to sort of the current state of health care in the UK. But that's probably for another time. I imagine much harder to be sort of that kind of very deliberative personality. Yeah, you've got to be you've you've got to be on it the whole time. And the amount of time you've got to be on it is rapidly increasing.

But, you know, that's that's that is the way it is. So I've got a hard mode version of what exactly is going on. And this is this is this is sort of taken straight from Leverson. So next slide, please. What is wrong with computer brackets? Alice will not understand. Yes, I mean, I say this is not my wheelhouse. And this is me sort of looking through this, reading this several times

and then sort of trying to sort of approximate it from my own sort of knowledge. But so you have a monitor task, which is called treat. And this has eight subroutines, date and being the data entry task. And it communicates with the keyboard handler task. That's the bit that tells you what keys you put in. And that shares a variable in the data entry called data entry complete. When the prescription data has been entered, the flags change to denote this. And when it's set, the treat subroutine moves to variable three, which is set up test.

It exits that and then restarts the treat subroutine. In the original version of the software, the to determine whether the data entry was flagged as complete, depending on the position of the cursor on the command line at the bottom of the terminal screen, but not when it had been moved subsequently. So it just it's not intended for you to edit this again. Like what the programmer has in mind is you put in the prescription details and you get it right, you get it wrong, you ditch the whole thing,

start process from like beginning. Yes. And then it's not entered again. If it's been flagged as complete, it would usually force the technician to enter the prescription data. Except when X-ray photon mode is selected. So this is why the eight seconds is quite quick, because it's got to go through they've got to go through and put every bit of prescription information in. If it's electron beam,

if it's actually it just defaults to 25 mega electron volts and skips back down to the bottom. So this is the portion of the software that sets another task in which hand, which sets a position of the treatment head. But because the data entry has not been exited and won't be entered again to in the cycle, there's no way in the software to detect the incompatibility between the treatment information entered and the treatment head setting. Huh.

So then the final bit of this software is called a subroutine called magnet. And that sets the that's where the eight second delay is relevant. So this has an artificial delay introduced to account for the time it sets. All of those electron magnets up to deliver the beam. And that's set up using a routine called P time cycle through several times and checked with the keyboard handle to see if there are any edits made. Of course, where it executes because it clears that flag,

then it never detects that there's been an edit made and defaults back to the data entry. So giving you the eight second when watching a gun being assembled, it's horrible. It leaves eight second windows possible to edit the modality and dose. Have it be displayed correctly on the terminal screen, not be recognized by the software and then resulting in the two overdose incidents that were at East Texas. That's such a like easy thing to miss that like. No, it's software is perfect.

Yeah. So the FDA, the the radiation scientists, you know, they are continually bullying AECL throughout all of this. The FDA are similarly scathing with internal memorandum. Levison managed to get hold of some internal memoranda for her report and indicated that they possibly omitted awareness of previous radiation safety incidents involving the Fair Act 25, having settled out of court. The injuries sustained by Katie Yarbrough's

at the first victim in Marietta, Georgia. Insufficient detail and clarity of their quality assurance process with no response provided to the Canadian radiation protection board after they requested further details of software revision and requirements. So this is Gord. So they didn't reply. So they do you just say, Gord's emails. Did you just say Canadian?

Yeah, that's what they should call it. That's like, yeah, there's always a background level of Canadians around. Yes. And but then above that, that is like an error, like a point at which you might stochastically be exposed to a Canadian in a way that increases your risk of consuming like maple syrup or like saying a. Yeah. Yes.

So so they they ignored they basically because they settled the first incident out of court, they didn't they were settled out of court. You can't, you know, we settle this out of court. You can't get mad at us. We settle a cell intended to keep the obscure and undocumented error codes. Which the FDA liked them, you know, I'm not sure why, but they did. FDA demanded they would change to provide more explicit warnings. And then they did not plan to do any additional QA

to ensure exact copying of the updated software to the install devices or test any further updates to software to ensure safety. Just remarkably like lackadaisical about this. So they produce you fine. Don't worry about a revised corrective action plan was published on the December 22nd, 1986. This implemented suspension of treatment for dose error was detected and a planned implement and a plan to implement meaningful error messages.

Oh, good. Yes, a pretty, you know, yeah, we make a plan, you know, make a plan to have a committee to sort of work out what is meaningful in the context of an error message. What was so difficult about error messages at this point? I mean, I guess I understand that like now in an age of everything where it's like, oopsie, whoopsie, the computer made a fucking work here. You know, you might not want to have to like delve back through like error in blocks, zero X, whatever.

But like this is so it's such a weird point to be insistent about. Why not give the why not give the operators a print out of the error code documentation? I feel like that's a nice quick interim solution here. Yeah, this is this was the revised plan and everything was fine at this point. Then all the major safety issues have been addressed and the federal oversight had been successful. Please don't say a date now.

January 17th, 1987. Fuck. Yes, this this has a fake ending. The third 25, it's like it comes back from the dead. Yeah, it kills someone else. It was not done yet. This is so on this case, an unnamed patient attends the Yakima Valley Memorial Hospital for treatment of a car soma.

Again, no further information about the cancer itself. A second patient of the day and they are intended to have two film exposures. So basically, they do a low dose X sort of that sort of low dose X Ray with a film underneath the patient to sort of say, how have we got the right place and then a high dose X Ray treatment with a 10 intended total dose of 86 rats. So very low dose. So this is the 80s and so taking an X Ray requires you actually

placing a physical X Ray photographic film under the patient. Perform the first doesn't some places. You can get like Russian like we used to be able to get a Russian X Ray film relatively readily that you can make some very interesting film exposures with because it doesn't have like a halation layer or whatever it is. So they did the first return to the treatment room set the beam for the second upon returning the road. So they sort of set the beam for the second X Ray did the second X Ray

rotated the treatment head from the into the field like position to check the positioning for therapeutic treatment. At this point, they inadvertently left the second X Ray on the second exposed film under the patient. You know, these things happen, you know, you're treating some of all the patients. You've kind of got two films. You've taken one film, they left the entry film under. So we

substituted so we have the hand command on the terminal in the operator room. And you can also position the treatment head using a hand control as well. So they they in this case, they set the dose using the handheld unit, went back to the terminal room, displayed beam ready, having installed the prescription information, the operator pressed the B key for beam ready. Again, again, beef of beam, P for pause.

If you would, you know, literalists, Canadian literalists all the way through. The beam came on, but no dose information was displayed. The operator in deposition stated there a message may briefly have been displayed. However, the treatment was simply paused. And as the operators are used to doing this point, they pressed the P key to resume treatment. The machine paused again. And the so we have the upgraded error messages here.

This one was flatness. Could that possibly mean? We have in like the past couple of hours, if we heard of anything that you could express in terms of like topographical flatness, like I think this is sort of to do with so. So we sort of talk about beam flattening in in. OK, I suspected some things over that. But again, this is this is the supposedly upgraded error system.

And this is this is, you know, this is sort of errors at the beginning. But the things that the machine only displayed that dosing information for two X ray films, seven rats. The operator went to unpause the treatment for a third time, but heard the patient moaning from the treatment room of the intercom and went to check on them. They reported a sensation of pain and burning in the chest and over the next several days that developed into a burn with the characteristic strike pattern

matching slots in the blocking tray. Very similar to that seen at the previous Yakima Valley in December of 1985. So sort of two years, sort of a year or so before. ACLs initially recommended users should manually confirm the position again, this is this is a new problem, not a last problem before positioning. Of course, an engineer was dispatched from Ottawa in the meantime. Medical Physicists Yakima Valley conducted their own investigations

and they managed to achieve production of X ray beams in the field like position. Oh, good. So there's nothing attenuating that? No, so there's no so there's no electron beam control. There is no tungsten. This is just coming through the diagnostic. Diagnostic, yeah. So they tested this onto X ray film and they compared it with this again. Another fantastic bit of.

Forty, they'd actually left the X ray film under the patient because they were able to compare the X ray film that inadvertently left under the patient affected with the simulation films they ran. And they noticed the patch in a match in the patterns displayed on the two. So again, another huge win here for medical physicists, knowing what they're doing and radiation detective work. Yes, there's some fantastic detective work here. The patient was determined to be lived

at up to 10,000 rads and they died in April of 87 relating to complications from the radiation exposure. While they had advanced cancer, they the family brought a lawsuit again to ACL that indicated that the radiation exposure has hastened their death. And again, this was settled out of court. Naturally, what? The ACL determined this could not be entirely

due to hardware and determine the unit was awaiting an update to the software following the conclusion of the FDA corrective actions. So it hadn't had yet the software update from the East Texas instance. However, this fault was an entirely separate quirk of the operator software. Incredible. Third one. Second, second.

Yeah, second, sort of because they think that the Hamilton one was probably the same thing as well because of the light that the remember that in Hamilton, Ontario, that's where the patient had the sort of line pattern. So they expect the same thing may have happened, but that was never determined. So once again, we're going back to this argument, it determines the position by the micro switches. They've already had the hardware revision following the incident in Hamilton. It made modifications to the hardware, software was unchanged,

and a different failure mechanism was the culprit here. So this is, again, I think we're on to hard mode now, because what next slide, please, happens here is wrong in what goes wrong in computer to more hard mode. The software floor here is that is what was a race condition error. So there's multiple competing processes carrying at the same time. Position of different timing problems, a different timing problem, time related.

Yeah, this one writes the position of the head matching that in the prescription data, and it's got a housekeeping program process called LMTC, Elmut check, which sets up a single bit in one shared variable called F dollar mal, and if this is set to zero, the code enters the setup done stage of the treat algorithm. It does this by working through an eight bit counter called plus three, it increases by one each time the setup test portion of T phase runs. This is going through multiple setup runs, as we talked about earlier.

It's an eight bit counter. So the maximum we can count to is from zero to two hundred and fifty five. So if someone were coincidentally to press the set button on the hand control at the exact moment that variable rolls over again to zero, the software wouldn't enter the head position check mode and would instead display that the beam was ready to fire. That's so weird. And it's purely like dumb luck that you have to do this.

Yes, it is simultaneous. Which is why this machine was used. So it happened on two, possibly three occasions out of what is likely hundreds and hundreds of uses just because someone happened to hit the button at exactly the right moment at which that bit flips over from two, five, five to zero. This is such a I mean, statistically, though, that's statistically, though, that's like 0.3 percent of times, which is a lot. That's a lot of times for the software to run in such a way that it kills the patient.

Yeah. So. I think we sort of would post three hours on this point now. I think we can sort of wrap things up a little bit. So there was a back and forth with the FDA essentially at this point, multiple lawsuits that were settled out of court, which is why we have very little information, the extensive sort of hardware changes were made to the to the device. And it's too expensive to like just throw them all out.

I presume you have to find a way to like fix them and keep them running. Yeah, exactly. So they had to make multiple sort of alterations. The hardware what they basically did was reconstruct sort of retrofit this machine back to being essentially the the THERAC 20. So what they had to do was introduce hardware and slots on the therapy head positioning system.

They implemented a turntable potentiometer to independently monitor the therapy head position. I think we're on next slide. If we haven't got that, yes, we have. OK, good, great. The other thing that had to be implemented was it was a dead man switch in the operator room. So to actually make the thing work, you have to have your foot on the pedal.

Otherwise, it would not fire. A hardware shut down circuit was introduced, independent hardware control shutdown circuit, hardware interlock on then the bending magnet, so ensure that it can't fire when the tungsten target is until it's in the correct position, limiting the editing keys to cursor up, back to base and return and hardware interlocks again from preventing the beam from turning on the field like you can you can put your up arrow key back on the keyboard and you can find it out of the cupboard and you can take the tape off

and you can stick the heart of the up arrow back on. They eliminated the sufferers in the East Texas Yakima Valley instance. They changed the error messages to be meaningful, although no description has been made of what meaningful means of the circumstance. They had an additional software shutdown mechanism and what were described by Leverson is 23 other changes to improve reliability of the software.

They finally, after six instance, acknowledged that any errors resulting in a treatment pause would instead suspend the treatment. And they prevent you go to like inconvenience your user a little bit and prevent a sort of on-site copying of code. So all the code had to sort of, you know, they had to sort of centralize the sort of code so that all the updates were sort of applied simultaneously. What Ed Miller, the director of the Division of Standards Enforcement at the Centre

for Devices and Radiological Health, the FDA wrote in 1987, was that the FDA has performed extensive review of the THERAC 25 software and hardware safety systems. We cannot say with absolute certainty that all software problems that might result in improper dose have been found and eliminated. Oh, cool. OK. However, we are confident that the hardware and software safety features recently added will prevent future catastrophic consequences of failure. That was inshallah.

No further THERAC 25 instance has were reported. 30 years with everyone watching it like a hawk. Yeah, presumably are now at the end of their lives anyway. Yeah, I mean, they may have the likelihood is these were probably all, you know, again, these cost a million dollars each. But then in terms of litigation costs, they probably reaches a point whereby it's cheaper to replace it with a unit that doesn't

cause catastrophic radiation injury rather than always going to have one or two one or two patients are going to walk in the room. They're going to see THERAC 25 printed on the unit and they're going to be like, nope, oh, yeah, I want a second opinion. No, thank you. I mean, the good news is that this like is now enough of a case study for like software engineering, I would hope and pray that this leads to sort of like a change in mindset of how you write software for applications or something

that can kill a person. The software was largely on all of the tests were on the hardware. So they sort of wrote the software. But they didn't, you know, the errors weren't documented. The error conditions weren't documented. They didn't go through the same QA procedure as the hardware. And they this one of sort of Leverson's critiques of the software is that it's massively overengineered.

So it's too complex for what it's supposed to be doing. What it's supposed to be doing is is set up the electron beam. Change the mode. Fire the beam. And what it's trying to do is kind of keep juggling sort of multiple sort of variables that sort of calling back on each other. And it's and sort of you know, you're creating the conditions for which this can fail by introducing these sort of race condition errors because you're

relying on the fact that people don't do weird things with software, which people do all the time, you know, we talk we talked about speed running earlier. And effectively, speed running is sort of ways of just like, you know, very, you know, reproducibly breaking software in accidental ways that are not supposed to happen. And that's sort of kind of the thing that sort of happened here. And that these, you know, you know, these these errors occurred because I sort of tasted, let's say, with speed running, that, you know, OK, if you are an average person,

if you're the average engineer who came in to sort of inspect the device in Texas, they couldn't reproduce the error. You know, the person who could reproduce the error first was the operator. And they could really reproduce the error. And then the medical physicist and then eventually the engineer having sort of been shown how to do it. But it sort of takes a lot of once. They believe them once they believe it seems they're very reluctant to do as well.

Yeah. It's just like refusal to actually trust the operator of your product when they say that it has like a failure condition. And let's say that every medical physicist that was involved in every you know, radiation protection officer that was involved with the you know, these incidents cottoned on to what was going on. And it was really a sort of a race to reproduce the errors before, you know,

the sort of, you know, there was legal consequences or sort of, you know, things were sort of scrolled away because things were settled out of court. And it's only thanks to sort of the extensive documentation that was made by these people that we've got any idea of what went on in the first place. Because the existence of this thing has been, you know, scrubbed, it has been scrubbed from existence. Barely has a Wikipedia article. So that has like three, you know, three sections of which it's, you know,

sort of presented as a mild case study. I think that sorry. This incident always, you know, brought up like a at least something I thought it did, which apparently it didn't bring up the idea of professional licensing for software engineers, right, where you work on like a really safety critical system like this, you know, if you are, if you're a civil engineer and you pulled something that did this, you would go to jail. But if you're a software engineer, it's like, OK, we made this very complex system

that we said is 100% reliable and it results in several deaths. Well, you know, whatever. And I thought after this, you started to get like a movement for professional licensing for software engineers who work in these sorts of safety critical, but otherwise relatively simple systems. This has not been the case. I think I think in total there have been 44 software P.E. licenses issued in the entire United States.

So it's not common. It's still you have, I guess that's how you can get away with things like Tesla autopilot or the self driving, full self driving stuff where the car homes in on kids and kills them and there's no one experiences any liability from this. Yeah, I think it's easy to like generalize, especially like we've seen it here where it's like it's a one person, one unknown person becoming computer people because it's like a lot of people do not understand software engineering. I certainly don't.

And therefore it becomes the province of like people, the people who do that. And, you know, that's that's their responsibility. It's just it comes out of the computer somewhere. So if they were a structure, there would be a stamp with a name on it and a number. Yes. Yeah. But no one ever wants to do more regulation apart from us. One thing that sort of sort of in in terms of this and was sort of this is sort of an expanded discussion that could go on.

But what Leveson says in her sort of critique of everything is it it often takes an accident to alert people to the dangers involved in technology. I'm quoting directly here. And a medical physicist wrote about the Thurrock 25 instance that in the past day, quarter or two, the medical accelerator industry has become a little complacent about safety. We've assumed that manufacturers have all kinds of safety design experience since they've been in the business a long time.

We know that there are many safety codes, guides and regulations to guide them. And we have been reassured by the hitherto excellent record of these machines. And except for a few incidents in the 1960s, each year, Hammerswith Hamburg, the use of medical accelerators has been remarkably free of serious radiation, radiation in accidents until now. Perhaps though, we've been spoiled by this success. And the comment that this problem seems to be common across all fields. So, yeah, that the sort of complacency about, you know, this is this is, you know,

these previous devices were fine. And, you know, the software people know what they're doing wasn't the thing here. And just a brief thing on this sort of next slide is to sort of wrap up. The main question that's a lot of people ask, you know, this device was able to come to market with two software mechanisms that could deliver a fatal dose of radiation. So what sort of testing was involved? What sort of FDA licensing process was involved?

And the licensing process involved was something called pre-market notification. So this was introduced because it was designed in principle, this is quoting directly from the FDA, that the device to be marketed is safe and effective in that is substantially equivalent to a legally marketed device. So because we've seen this happen as a loophole with the car industry, we've seen like dangerous cars get through because they've managed to convince the Department of Transportation that it's not a substantial, it's like it's not a new model.

It's like a slight refinement of an existing thing that you've already passed. Or maybe an airplane. Or an airplane, yes. So the Therac 20 and the Therac 25, because the Therac 6 was on the market and had already gone through the full approvals process, neither of the other devices were required to go through the same and they entered the market because of the 510K procedure. Because it speeds things up, it allows you to iterate, it's efficient. I mean, it's also something else that

harkens to the 737 MAX is, as we just said, it's the airline industry too. As one of these industries that has benefited from success because it is very safe. It knows it's very safe. It considers itself to have a safety culture. And that was precisely the way that allowed it to be so complacent about these things is because when you have this evidence base of safety, it allows you to go, well, this thing that happened was probably just an aberration because mistakes like that do not happen in our industry, they don't happen to us.

No, this is the thing is, is that while the FDA did change its procedures here, so they did implement a way by which end users were then able to record sort of errors and report errors with medical devices and software. Because this is obviously, you know, softwares are things in relative infancy at the time. They still have issues with medical devices. So subsequently to the THERAC 25, there's been other device scandals which have occurred in sort of the special use work on which orthopedics.

There was a particular design of total hit replacement with a metal on metal bearing that came to market because it was a modified version of a previous design. And the previous design had undergone all the previous safety procedures, even though it had an entirely different bearing surface. And that resulted in lots of patient mobility, where these things failed early because of the eccentric wear on the cup. This is that's an episode in itself. And also sort of transversional mesh implants is the other big medical scandal.

So these are sort of implantable meshes that were originally developed sort of to repair sort of hernias. But then they applied for a license based on the fact that we use these to repair hernias, uterine prolapse is kind of like a hernia. It's still going in the abdominal cavity. Basically the same. And there was a sort of, you know, there was a BMA investigation to one of this. And they sort of found there were sort of tens of different devices all having

spun off from this one parent device, all doing completely different things in different parts of the body, made of different materials. And in the case of the sort of vaginal transversional mesh implants, a huge scandal that's left lots of people civilly, you know, disabled incontinent, all sorts of horrific consequences as a result. Just sort of an easy way to get your foot in the door of regulations. You get one thing approved and then just anything else like it. You can just like, yeah, sort of slide through.

All right, the last thing was good. This one's probably good too. I'm going to prove it, Bill. And it's in medicine. It's this sort of there there can just sort of be an element whereby this occurs in one specialty and everyone sort of goes, well, well, that would occur in that specialty. But those idiots over in the radiology department, they might do that. This will never happen to me in the urology.

So I think I think this is that, you know, where there is a good argument for sort of saying, well, you know, you've got to kind of keep abreast of what is happening in other areas, rather sectors of your profession. Because, you know, what's happened in one has happened in another and it's happened multiple times and any need to have some sort of level of scrutiny of all new devices coming to market since so in, you know, and after every one of these, there is then the push for regulation, but in a specific sector. So the this HIP implant, which is something called the DPU ASR.

So as a result of that, lots of places, the US and the UK did change the way that they sort of record medical devices. They're much more stringent about what devices they've implemented, basically a complete iron or metal or metal hit bearings being used. Then, you know, there's there's several other fields whereby there are loads of devices on the market with the market notification and I think caution, you know, yes, it does drive innovation. I think it's important to have health care innovation from a personal standpoint,

but at the same time, you know, be aware of sort of making huge, dramatic changes to one device or just an easy way of doing regulation on the cheap because governments don't like regulating things and manufacturers don't like being regulated and the only people who benefit from regulation are clinicians and patients, you know, and who cares about them? Well, I think we've we've learned a lot about the third 25. Yeah, it's good. I'm glad to have written a thesis.

It's fantastic. We think we have time for safety third or do we want to get an early night after a mere three and a half hours? I want to get it. I want to go get some food before everything closes. Oh, fair enough. Yeah. Thank you so much for coming on and writing the slides for this.

That's a little one. It's been very entertaining and yes, we'd love to have you back on any time we get anything even tenuously medically. That's fun. I'm happy to come back. Yeah, I have I have. Sorry, I was just going to say our next episode is on the Chernobyl disaster. Yes. I was people want more time.

Where can they find you? So I have nothing to plug. You can you can find me working in the NHS, although you struggle to find me because I sort of in a lab most of the day. I the only things I would say at this point, if you're certainly if you're in the UK, you know, please support the nurses who are on strike at the moment, please support ambulance drivers on strike. The BMA is holding a strike ballot in two days time for junior doctors to support

junior doctors when we go on strike. And at some point it looks like there may even be a consultant strike. As an indication of how problematic things are in the NHS, because yeah, we are losing good people at a rapid rate, and it is at all levels of the organization now. It's incredible how Jeremy Corbyn did this. I don't know why he did this, and I don't really support him doing that. Well, we have a Patreon.

You can subscribe to it. You get a bonus episode when we do a bonus episode. We do them as quickly as we can, which is not very quickly. Yes, we are also falling apart, but without any of the other like institutional pressures, we're just also doing that for fun. And, you know, please do that. We would be very happy to take your money and we'll see you next time. Yes.