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Testing the Credibility of Linear No-Threshold

Dr. Douglas Boreham and Dr. Chris Thome

Monday, July 4, 2022

Chris Keefer  0:03  

Hello, everybody. And welcome to the Decouple podcast, where we explore the science and technologies that can Decouple human wellbeing from its ecological impacts, and the politics that can make decoupling possible. Welcome back to Decouple a special recording from the Canadian Nuclear Association Conference here in Ottawa, Canada. And today I'm joined by my good friend, Douglas Boreham, veteran of the podcast, radiation biologist, you have a lot of qualifications, and I'm gonna stumble over Doug. So don't worry about wanting to do the famous self introduction, just give us give us a tad bit more than I have.


Dr. Douglas Boreham  0:42  

All right. So I'm a radiation biologist, I worked 10 years at Atomic Energy of Canada and Chuck River, then went 12 years at McMaster University and their medical physics department. And now I am the division head of the medical school or the now the medics Northern Ontario School of Medicine University. On the side, I also worked at 12 years of Bruce Power. Okay. We had that episode two years.


Chris Keefer  1:04  

That's, that's fair number of years. I'm doing some calculations in my head right now. Yeah, Douglas. I mean, I'm really lucky, I have a lot of excellent guests on the podcast, who then sort of become sort of Special Advisers that I can reach out to with questions. And we had a really interesting interaction recently, because my dad is actually being treated for prostate cancer with the medical isotope lutetium 177, which Bruce Power is working on being a major supplier for, right. But I looked at his hospital discharge instructions. And I had a sense of how insane they were, but I'll just share some details. He was supposed to move his bed three meters from the nearest wall, he had a big house. Exactly. I mean, who can who can do that? No public transport, couldn't sleep in the same bed as my mother, for quite a while had to flush the toilet three times after every use, and then in to do a full swab down of the bathroom. I think after week one, you know, so I remember reaching out to you and saying, this, this sounds insane to me, but it's great. So you know, I'm not a radiation biologist. So it was it was, you know, it's just a pleasure having you in this network of that. Yeah,


Dr. Douglas Boreham  2:08  

so we Decouple experts, it's a bit of an overreaction when we looked into it, and I think some of these regulations that we have, or guidelines that we have for medical isotope uses in the future gonna have to change a little bit because it is, not only is it inconvenient for the patients, but it's it's quality of life to write and you get, you're getting treated for diseases, really, really bad disease. And then now you have to go through all this other stuff, when really you don't have to, in fact, most of that stuff is out of the body for biological half life within a couple hours. And then the other step, because of the half life, it has it decays away in a very short period of time. And the dose rate that you're giving off to someone beside you this the almost identical dose rate that you get sitting on an airplane at 30,000 feet, which is four micro sieverts an hour, which is biologically non a non starter.


Chris Keefer  2:55  

So you take a cancer patient who's got enough on their plate dealing with that diagnosis, and who needs the support of you know, not just their community, but their family, and you say you got to basically sit in a room all by yourself three meters from the nearest wall. You know, and that causes real harm. And I don't think I think we have a real hard time with understanding risk in our society and weighing risk and benefit. Anyway, it was very useful to, to call me up Yeah, to go from about 95% certainty that this was insane to write a high percentage and get so Doug is one of the reasons that our listeners really enjoyed your episode is you bring a lot of, you know, for our science nerd audience, you bring a lot of really cool stories. You


Dr. Douglas Boreham  3:40  

do science? Yeah, we do have is gonna be fun, right? I mean, what's the point? It's gonna be fun.


Chris Keefer  3:44  

Awesome. So we talked a little bit in the podcast about snow lab. Right? I'm gonna think we're going to talk with one of your colleagues a little bit about the research that's being done on radon and, you know, basically no radiation environments. Yeah. But you were just telling me about the NASA project sending yeast to space. So let's first science nerd audience. Let's start with


Dr. Douglas Boreham  4:04  

that. So a little bit about that, if you heard me just mentioned a second ago about the the radiation that people get flying? Well, that's cosmic radiation, right? There's a lot of cosmic radiation out there, especially when you get outside of the atmosphere above and beyond low Earth orbit, low earth orbit, where the space station is. We're sending people to the moon next year, or 2024. And then then on to Mars. And many challenges. We have many challenges as a human in space, but one of them is cosmic radiation. And that's where we come into it. We were collaborating with NASA and their, their punch line is, you know, NASA sending east into space or no use has gone before. And, and it's very interesting because yeast, from the perspective of research are a perfect astronaut, because right now we don't have the ability to send a living thing deep into space, and we're talking 40 million kilometers out into space, and be able to monitor it and know it's alive, and then assess the the effects of this cosmic Radiation is out there. And you know, the astronauts even in low Earth orbit or when they went to the Apollo mission, they get hit with a lot of great cosmic radiation. And to the extent where they get flashes of lights, flashes of light in their eyes from heavily charged particles going through their head, the retina and back up their head again. So there's going to be biological effects of this kind of stuff. So by sending these yeasts out into space, and the reason I say they're perfect astronaut is because they don't need to drink, they don't need water, they don't need to breathe as an important thing. They don't really care about the temperature. And so they're very low maintenance. So they don't eat, they don't breathe, they don't need water, and they don't care about temperatures. So now they're off, they go into space, and about every couple of weeks, a little robot on this E spaceship wakes couple of them up. So they're in a state of what we call an hydro BIOSIS, which is life without water, right. And when you rehydrate them, they immediately come to life. When you make your pizza or your beer you put in freeze dried yeast, poof, they wake up. Yeah, they're a eukaryotic cell, which is a cell that were made up of 100 trillion eukaryotic cells. These are individual eukaryotic cells. They're in a desiccated state. And NASA is very interested in that. Because the desiccated state could almost be like a state of Hybrid Hybrid hibernation. And part of what the research that we're doing is we're trying to figure out how we can put humans into hibernation to go to Mars, it'd be a triple lot easier.


Chris Keefer  6:16  

How many? How many days? Is it currently to live there? Six months when the planets line up correctly? shot someone there


Dr. Douglas Boreham  6:22  

six months? Wow. Yeah. And then six months to get back. And it's six months, you're gonna hang out there. So yeah, it's gonna be a stressful thing. So no Hanky Panky and space currently not suggesting that's not a good idea. I'm sure they've tried it already in the International Space Station, but I'm not gonna go I don't I don't I just made that up. But yeah, so these these are going into space are getting irradiated with this cosmic radiation. And when the when the robot wakes them up, we can get into a determination of how well they're repairing themselves, as they go deeper and deeper into space. And, and we also have two strains of yeast one that has the inability to fix what we call DNA double strand breaks, which are the critical lesions when it comes to the effects of radiation. I mean, you want to you want to have a lot of double strand breaks in tumor tissue in your radius, you want to kill them, and that's a kill them but making double strand breaks in DNA. These that don't have that ability to repair were going to be impacted much more by the cosmic rays, they've been genetically engineered, they've been bad repair mechanism, one gene has been knocked out. It's a gene has a repair system called route homologous recombination. And that allows them to fix double strand breaks and not making mistakes. So in other words, not mutate. One yeast, blacks, that ability, the other uses what we call the wild TVs, and they're going off into space. And so what we're doing is we're looking at how these things are going to behave to different types of radiation. And so we have the snow Lab, which you'll hear about that has no cosmic radiation, and no other types of radiation. And we're gonna see how those us survive under those circumstances, and how they're surviving in deep space. And that's the way to compare what biological mechanisms are actually at play by keeping eukaryotic cells alive in space. And then there's gonna be a number of countermeasures are we gonna try and come up with to protect the eukaryotic cell from this cosmic radiation, we we've we've taken these yeast in this desiccated state to a radiation facilities that can give very high doses of radiation. Now, for example, if you're getting cancer treatment, you get about two gray per fraction, right to gray a day.


Chris Keefer  8:13  

And as a whole body dose, that's enough to hold on.


Dr. Douglas Boreham  8:17  

That would be high, I would Yeah, some people would definitely notice that too great. Nobody knows but a to grade dose to the tumor itself. That's where you get the effect. And you know, as you know, you don't put the two gray into tumor all at once you put it in at different angles and different, different beams. And then that way, the normal tissue around it only gets a little bit of radiation, right, it all builds up in the tumor to give you your two grade exactly that to grade and causes roughly 80 or 100 double strand breaks in every cell. And that can kill the cells, not all of them, but they'll repair and then you do it again, you do again, that's where you go every day to get this race therapy, these desiccated yeast, we've given them already up to 2000 Gray, so 1000 times more than when you get in a radiation therapy treatment. And about 3% of it survive, which is amazing, though, so part of what we're doing with this is an extension to that we can actually use this use model system to look at how double strand breaks are formed and how cells repair. And one of the newest radiation therapy treatments that we're coming up with is called Flash radiation. And that's instead of giving a two grade dose of radiation to a tumor, roughly over 30 seconds or a minute. This happens in a millisecond. So we they can deliver doses in what's called Flash radiation. So 100 Gray a second. That's a lot of bills. So it's a flash, right. And the interesting thing about it is that if they get flash radiation to tumor, it looks like the tumor cells are affected by the the yeast can't repair itself, but the normal tissue isn't. So it protects normal tissue flesh radiation, we're going to take the system and we're going to do flash radiation on them. And that'll help us understand how giving a dose of wheat it took us 24 hours to give a dose of 2000 Gray, and we're gonna give a dose of 2000 grade in literally less than a few minutes.


Chris Keefer  9:58  

So huge, huge applications. Back here on Earth. But you mentioned a couple statistics around these double stranded DNA breaks. And one of the big things that was the takeaway, I think, from our podcast was just, you know, at the dawn of genetics and understanding the DNA double helix, etc. We didn't have that appreciation of the repair mechanism. So I just wanted to I think that's a great thing to demystify. In terms of single strand and double strand breaks, how often that are those just happening spontaneously in our cells as a result of, you know, oxidative metabolism,


Dr. Douglas Boreham  10:29  

metabolism. So I guess the example I would use is, if you get a CT scan, you get the what we call 10, Billy Graham dose, that roughly equivalent to 10 photons through each cell in your body. If you're sitting waiting in the waiting room, breathing oxygen for an hour, getting oxygen metabolism damage, there's 10,000 times more damage in that one hour from breathing oxygen there is from the actual photons caused by the CT scan. So people don't appreciate the whole idea of oxidative stress and, and oxidative metabolism and how that damages their DNA. I mean, the single strand breaks that you think about it, we have two strands of DNA, and they're complementary to each other if you get a single strand break, and one repair system can fix it easy because the template is a copy, right? So you have a backup copy, you just patch the hole and you're good to go. When you go when you break two strands. Now, where do you get the information? Well, we just so happen to have two sets of chromosomes, right, we have two number ones, two number twos. So if you break a double strand break in chromosome number one, here, you find the homologous chromosome, and you can do what we call homologous recombination. So you actually have backup information on your second copy. And our second drive, backup hard drive, flash drive, you have two of them, right. So this one doesn't work, you copy the information over and now it's repaired in the same way it was what happens is sometimes there's mistakes being made. And that usually happens from what we call non homologous end rejoining, and that's when the cell just sticks it together and doesn't put in the right basis, that kind of problematic. So other than that, it's, I've heard,


Chris Keefer  11:50  

I think in the average cell, there's 10,000, single strand breaks a day, something like that, oh,


Dr. Douglas Boreham  11:55  

there's more than that. I think it's an hour, it's a, I have to get the number on that. Unfortunately, it's 10,000 DNA alterations per hour in a cell, not necessarily single strand breaks. But wow. So like a single, a one grade dose of radiation in one cell will probably cause two to 3000, single strand breaks, and somewhere around 40 to 50 double strand breaks a single grade, right? And cells can repair that they can handle that and they can manage it. So you mentioned DNA repair. But we also have mechanisms in our cells that will say okay, the repair system somehow failed. And the DNA is not right. So what the cell does, and this turns on genes are called tumor suppressor genes, which causes cells to self destruct seppuku as a Japanese. Exactly. And you know what a dead cell can be on the cancer cell, right? And we're roughly having in our body, 3 million cells commit suicide every minute. Yeah, that's, that's to keep the genomic stability and and we replace 3 million cells every minute. And that's what keeps us balanced and keeps the cells it's funny,


Chris Keefer  12:58  

you mentioned that CT scan, because I think there's a strength that, you know, I have as a physician, and you have someone who works at a medical school, being able to compare radiation doses to everyday things that people experienced. And, you know, we have this background radiation dose, and the component is artificials, about 15%. And 14%. Of that is medical. But I was talking to Dr. Geraldine Thomas of the Chernobyl tissue bank. And she was saying, you know, the 6 million people around Chernobyl that were most affected, got the equivalent radiation dose of a single whole body CT scan, but over a 25 year period. So it gives you a little bit of a sense, because, you know, you really are so terrified of radiation. And it really is affecting, you know, the choices that we're making in responding to climate change, or you know, exactly,


Dr. Douglas Boreham  13:42  

and I think a lot of there's still a lot of people that believe and we were talking today about theology and math, I don't remember that. A lot of people that believe that radiation doses add up, right one today, you get one tomorrow, you get one next week, these add up over your lifetime in your lifetime risk then goes up our research and a number of researchers in my area, we don't accept the hypothesis of that idea. Because if you think about all the things that damage your body, including alcohol, if it was to add up, we'd all be dead, right? And working out would be a really bad idea. Bad idea. Yeah. So So you see, it's a it's a really interesting analogy that you can compare things and like, like I said, Before, when you spread things out over time, our cells have more time to repair, right, so let's have a easier time with fixing. So if you get a double strand break now and you fix it, you get one another hour from now you fix it. If you get like 40 of all at once in your in your you're gonna probably die, the cells gonna die. So how long is


Chris Keefer  14:33  

it gonna take for the radiation protection establishment to kind of catch up with with the science?


Dr. Douglas Boreham  14:38  

Well, I started this doing this stuff in 1986. Actually, I started my PhD the year Chernobyl went up, right in August of 86. And in those days, the whole idea was, when are we going to actually figure out that there's no such thing as a linear response to radiation and there's no such thing as additive risk. And there's no such thing as a collective dose, at least a collective dose thing, right? This is gone away. Right? Right. But


Chris Keefer  15:00  

from unsecure, I mean not not from Greenpeace, but


Dr. Douglas Boreham  15:04  

it just went away. Because the scientists, the scientists finally figured out that this was a step too far this was to Can't you just can't add up little doses of a big population and calculate risk to one person from all of those, or as a collective dose.


Chris Keefer  15:16  

And that's where you get these big numbers when Greenpeace says 200,000 People will die from Chernobyl or Yeah, the torture report in Europe, you know, three very ideological scientists and


Dr. Douglas Boreham  15:25  

use the model. I think they were predicting some 4000 cancer to increase cancer risk deaths in in the Chernobyl incident, and I don't think there was any increase. So


Chris Keefer  15:36  

that and except for thyroid cancer, obviously,


Dr. Douglas Boreham  15:38  

yeah, the thing that the thyroid cancer has always been a mystery to some people too, because in terms of what we call latency period, for when the time you get exposed to a carcinogen and the time when the certain tumors appear, there's a latency period, it's the time it takes for the cells to go through the multi step processes and become a cancer. So what happens is, what happened with the Chernobyl thing is that almost the only a year after these exposures to the IUD, which we know is at increased cancer rates, especially children, all these thyroid cancer stations. And some of the argument is, is that well, if you go start looking for stuff, you're going to find things, even if they're all cold, meaning they're not going to cause any problems or just a benign tumor sitting there. But they started finding all these things. So they showed a statistical increase, it's still unclear to a lot of people is was this a real phenomenon of actual, you know, ideen induced thyroid cancer, or it was a was a consequence of the medical process of looking for things and finding what percentage is Yeah, and what was screening effect? You know, I think, but the I think people should know, or recognize it. Yeah, some people are getting thyroid cancer, but it's not a lethal type of cancer. It can be treated with the actual ID and the cause. Right? So


Chris Keefer  16:46  

it's not quite homeopathy. Yes, you're not you're not diluting it down. But yeah, use the exact same.


Dr. Douglas Boreham  16:51  

Same isotope because it use it to treat it with.


Chris Keefer  16:55  

Alright, I mean, I can talk to you all day, for five minutes. 20 minutes later, when you miss pleasure chatting with you a word to be to be repeated. So thanks for taking the time here. Okay. Well, welcome back to Decouple. We are live here at the Canadian Nuclear Association meeting up in Ottawa, meeting all kinds of really interesting, fabulous people just chatted with Douglas Boreham. Radiation biologist, he told me that Radiation Biology is maybe a dying field that there's not enough people in it. So I'm really excited to have a second radiation biologists on to nerd out about all things radiation. I've got a special guest here, Chris Tomi. And the little I know about crystal means a student actually, of Douglas Boreham. But he's involved with a very interesting place called the snow lab up in Sudbury, and he's looking at essentially radiation free environments and its effect on biological systems. So Chris, welcome. Thank you. I gave you a pretty superficial introduction so he let help us get to know you.


Chris Thome  17:57  

Well, no, you're right. I you know, I started off as a as a student under under Doug warm but then got a degree in in medical physics and health physics, but kind of focused on the Radiation Biology side of things. And now I'm a professor up at the the medical school in Sudbury, at Nasim University.


Chris Keefer  18:13  

Awesome. Awesome. So yeah, let's say we have a lot to discuss. I'm really interested in your work on radon. But also, why don't we start off by you describing the snow lab because it sounds like a pretty incredible idea,


Chris Thome  18:23  

isn't it? I mean, it's one of a kind in Canada and one of only a few facilities like this in the world. So it was originally designed, it's just outside of Sudbury. And so it was designed for for Astroparticle Physics, and they're looking at things like neutrinos and dark matter. And so by going deep underground, they have that two kilometers of overhead rock, which basically shields out all cosmic radiation. And so when we move up the submarine started our Radiation Biology program up there, we kind of realized that this might be the perfect facility through some some Radiation Biology, because you know, they're going underground to shield from the cosmic radiation, that's a background source for their detectors. But we can use that facility to actually look at what is the effect of natural background radiation. And we can look at that by actually removing background radiation. You know what that one's fears about about ionizing radiation, what a lot of people don't realize is that it's something that we're exposed to all the time on a daily basis. I mean, not just medical. But


Chris Keefer  19:17  

the inference of the linear no threshold hypothesis is that any amount of radiation is dangerous, which, you know, on the other side means that you would assume that will no radiation environment is the healthiest thing around or the healthiest thing possible.


Chris Thome  19:29  

Exactly. And so that's kind of what what we're looking at there. And so, you know, all of these experiments are people do looking at effects of low dose radiation and really low dose rate kind of stuff. Right? You still have that background source in there. Right. So by going down into snow lab, we've set up a lab there, where we can look at what is the effect of removing essentially, all sources of radiation,


Chris Keefer  19:50  

right. So what are those sources? Because I think that's mysterious. Like it was kind of news to me some time ago that we actually had natural background radiation, right? Yes, but what are the main sources to human beings?


Chris Thome  20:00  

So we've got to clean it for one. So there's cosmic radiation. So that's what, you know, astronauts in space are exposed to a lot higher levels of that we get different types here due to the interactions of that with the atmosphere that contributes some to our background radiation. We also get some from just natural like radioisotopes in the grounds. It's things like uranium, Potassium 40, those types of what we call primordial isotopes, they've been around since the later half, we've got such long half life that they're still around and appreciable amounts. We also get some from from internal exposures from foods that we eat things that we drink, so there's low levels of tritium and drinking water. Potassium 40 is common in bananas and other foods like that carbon 14 as well. But the biggest source that we get is from radon. And so Radon is a key product of naturally occurring uranium. It's an inert gas. So once Uranium decays to radon, that's when it can seep out into things like basements and mines. And so we inhale radon gas, and some of those decay products give us a low natural background dose. And so that's where the majority of our of our natural background radiation,


Chris Keefer  21:04  

there's a lot of a lot of fear around radon, particularly around questions about lung cancer. And so I think Health Canada has some guidelines about how much you can be exposed to but what's, what's the state of the science in terms of understanding that risk or potential risk? Well, as of right now, we


Chris Thome  21:20  

still don't really know most of those regulations are just based on on epidemiology, a lot of it from uranium miners, but those cohorts, you know, have a lot of confounding variables as well, right. And so we still don't really understand what happened, like smoking is the main thing, and it's a huge, we know that. Yeah, all of those things, smoking in particular, functions really synergistically with with radon. So it's really hard with some of those cohorts to to understand what the risk levels actually


Chris Keefer  21:44  

are. What about Ramsar Iran, which is I think, has the highest national background dose of radiation, any human population on the planet? I guess it'd be over 100 times what we get here and Ray in Ontario, you know, are there is that a good population to look at? Because I understand most of that exposures, they live in these houses that are made out of, you know, not uranium bricks, or thorium bricks, but they you know, there's a high content. So what, what data do we have on that court? Well,


Chris Thome  22:08  

we have data that shows essentially nothing, right. And so that's one of the main arguments that people have against the linear no threshold model is that if you say that if you give a CT scan to someone that's going to increase their cancer risk? Well, we have people that are living in regions of the world that are getting 10 times or 100 times the natural background dose of someone here in Canada, and we're not seeing huge increases in cancer levels in those populations. Right. And so that doesn't really correlate to that LNT model.


Chris Keefer  22:35  

Right. Right. And I mean, that's that's the big thing with the I think some of the Fukushima evacuation controversy if you were to apply on a radiation level, the same sort of restrictions in terms of where people can live, you'd have to evacuate certainly ramps around you'd have to evacuate Kerala, India. So it's it's


Chris Thome  22:52  

Rocky Mountain states to cosmic radiation. Yeah.


Chris Keefer  22:56  

I mean, I love Colorado. You know, I'd love to live down there if I had the chance. But yeah, it's 1010 millisieverts, I think it's some of the higher dose rate places. Yeah. Which is CT scan a year or Exactly, yeah. Okay. So let's, we talked about some of these sources of radiation. So how are you eliminating these? You said, you know, I mean, first off, how deep do you need to dig to actually get away from those cosmic rays? Is that overkill two kilometers deep? And then what are the other measures you take to eliminate those other sources like potassium 40, your carbon 14 Or the other ones? Right? So


Chris Thome  23:27  

for our sake, it's a little overkill. So we're two kilometers underground, right. And that's equivalent, that two kilometers a rock is equivalent to about six kilometers of water shielding. So if you think, you know, in terms of shielding levels that you might have in like an x ray suite, or some of those, you know, rooms, it's we are overkill for what we need for a lot of the other experiments, the kind of Astroparticle Physics experiments, you know, they're looking at such rare events and particle interactions that they need to get rid of, essentially, everything that they that they can, right. So cosmic, I mentioned is one of our sources. We can pretty much get rid of all cosmic by going underground, right? The biggest ones for us then are we have some gamma radiation still. So we have natural radio isotopes in the rock around the lab. And so as they decay, they're emitting gamma rays. And so some of those will enter into the lab. And then Radon is the other big one for us. So radon levels down there are about around 150 becquerels per cubic meter. So that means if you want a cubic meter of air, the background is just a measure of how radioactive is exactly. So 150 Becker ELLs in one cubic meter of air means that in every second there's 150 Atoms of radon going through decay. And that's very little. I mean, it sounds like a lot. It sounds like a lot but it is pretty low. So Health Canada's recommendation right now is 200 becquerels per cubic meter. Okay. People have much higher levels in their basement so it's, it's still comparatively low.


Chris Keefer  24:54  

So how do you eliminate that that dose within the lab, right?


Chris Thome  24:57  

So in terms of eliminating in the whole lab, it's Have to do because it's constantly being emitted. But what we did is we built a specialized incubator to grow our biological samples. And it's basically like a very technical glovebox that we can work in. One nice thing about radon is it does have a very short half life. So it's got a half life. 3.8 days, right? So what we're able to do is fill up gas cylinders, compressed gas cylinders, with air Yeah, let them sit for about a month or two. Yeah, and then our radon levels will have decayed to basically insignificant levels. So stay on we can the secret is really stale age, stale air is like, you know, office buildings from like the 80s, where they you know, didn't recycle the air. But yeah, it's like you're breathing air. That's exactly, yeah. Which for us is actually a good thing, right. And I mean, the other thing we didn't really think about we're setting all of this up to is that not only do we have to control the air itself, right, but all of the materials that we're using all of the stuff to build our glovebox, the flasks that we're growing cells in, they've all got really low levels of uranium contamination in them as well. Right? So all of that stuff is emitting radon too. And so, you know, by building a sealed compartment, if we're not careful with the materials we use, right, we could actually have higher levels of radon as it as it admits. So we work with the snow lab has a great team of of engineers and scientists there. And they're experts in terms of radon control, and so they knew exactly what materials to use, they would have low emanation rates of radon. And so we built this, this incubator slash glovebox that has lower levels, the compared to the lab on the ground, but also lower levels and even just get on the surface up here. Right. So we're down below, I mentioned 150 was kind of the average in the lab there. Were down below one becquerel per year within the glove box.


Chris Keefer  26:41  

Now understand potassium 40 is a huge challenge. It's a naturally occurring radioisotope. And that's like 0.00, or something of all the calcium. Potassium is a dominant intracellular category. And I remember that from from my medical studies, I don't remember much of the basic science anymore. But yeah, you know, that's bathing our DNA, it's the predominant thing inside ourselves, and understand it's a significant dose radiation. So how do you grow these organisms with a potassium 40,


Chris Thome  27:03  

right. And that's something we're just getting into now. So we've through going underground in snow lab, by building this, this incubation chamber glovebox, we also have some lead shielding on that too, to get rid of the the gammas that I was talking about. So we can get rid of all of the external sources. But we have that internal source of potassium 40, because we have to potassium, something that all of our whether it's human cells, or yeast, or whatever we're growing, and they need potassium in order to survive, right. And as you mentioned, it's less than point zero 1% of all potassium is potassium 40. But that still gives an appreciable dose, especially when we're in that low background environment. Right. So as of right now, we've we've done all the calculations on our dose rates. Right now, without controlling for potassium, that potassium 40 is about 9098, or 99% of our current dose rate, wow. So if we can get rid of potassium 40, or at least bumped that down, then our different our sub background environment that we're growing these systems in, we can get that even lower, we're talking 200, to even maybe 1000 times less than you would get in our


Chris Keefer  28:04  

control environments. That's not easy separating, you know,


Chris Thome  28:08  

what I'm talking about one difference Exactly. And so there are companies that you can buy potassium that is enriched in potassium 39, which is the, the non radioactive form of potassium. And so we've obtained some of that problem is, it's expensive. And so to run even just a small experiment, you're talking 1000s of dollars just to get that potassium. But we've we've secured some of that. And so we're running the experiments right now. So before we kind of get everything going, what we've got to do is, is kind of culture these these, we're doing it with yeast right now, culture them for multiple generations in the low potassium 40 media, so that they kind of exchange the what the potassium that's already within the cells, and then culture them a few times to kind of get that their their internal potassium levels are going to be meaner, that that key 39 and then bring him down to snow lab, grow them there for a while and really see what


Chris Keefer  28:58  

what we have data yet have we at Snow lab around the world that some of the other facilities, What effects do we see on biological organisms that grow up in either a mega, there's no such thing, even with all these measures in place that are no radiation environments and extraordinarily low background radiation? What what happens to the organisms in that environment?


Chris Thome  29:14  

Yeah, so there's snow lab is one of about three or four in the world right now that are where we, where there's biology experiments going on. And so what they found is exactly kind of what we would have hypothesized based on what we know about giving low doses of radiation, right. And it's the opposite from that LNT model. So LNT would suggest that if you remove background radiation, you'll live forever, things will be happy, the less, you know, less DNA damage, less cancer, it's less mutations. But in fact, these groups have found the opposite. And so when you remove background radiation, things do worse. They grow slower, there's more mutation. They're more prone to damage. So if you take a culture that's been, you know, some background environment and hit it with really high dose radiation to kind of challenge the system with with a high dose, they're not able to deal with that high dose stress as much. And so we see higher rates of DNA damage and mutations. And


Chris Keefer  30:03  

it kind of reminds me of like, you know, when you put astronauts in space and your move gravity, you know, gravity is is damaging, and you know, we spend our lives resisting it. And you know, you see these little old kyphotic ladies walking around like this, because of gravity has been weighing on their shoulders for their whole lives. Or, you know, if you put someone UV light from the Sun is dangerous. So, you know, if we were to live in caves and never see sunlight, you know, it's I think it's an analogous argument, where are you? Well, they should be able to live longer, because they're not being exposed to radiation. Or you can even take that further to say, and this is kind of Donald Trump's theory on exercise, right, that, you know, the body can only handle a finite amount, so just do as little as possible. Yeah. So is that is this kind of like a, you know, this seems like a bit of common sense. But one, is that why in your hypothesis is essentially that some is


Chris Thome  30:47  

good, right? And so the art hypothesis is that yeah, that little bit that you get a background radiation just kind of helps to keep things functioning, right. So when we've got anti oxygen systems within ourselves, we have DNA repair machineries that can fix single stranded and double stranded breaks. And so they're constantly working within ourselves. And, you know, some of that is from natural background radiation, some of its just from normal cellular metabolism, cellular respiration. So the theory that we have, and what other groups have is that by removing background radiation, that those kind of slowly start to shut down some of those processes, if you don't, if you don't work your biceps, there's going to lose atrophy away. Exactly. And so the same thing could be happening with our antioxidant and repair machineries within our cells and tissues. And so if you remove that background radiation over time, and it's not going to happen immediately, but if you're talking days or weeks in that environment, that they might kind of start to shut down some of those processes. And so when you do get your random mutations forming within the cells, they're not able to deal with that, as well as a normal background system.


Chris Keefer  31:48  

Okay. So, before we close, there's one area of controversy that's impactful here in Canada, because we have Canada reactors, and those do produce small amounts of tritium. And the anti nuclear folks raised this as being a major concern, because it's a you know, I guess it creates a molecule analogous to water and that distributes in the body. And, you know, I found it useful in conversations I've had with people that are worried about it to make that comparison to potassium 40. You know, they both believe do beta decays, but potassium 40 is like 70 times stronger. But can you can we just have a little nerd out on, you know, comparing tritium to other sources, how dangerous it is?


Chris Thome  32:21  

Yes. So tritium is one of the components of our of our background dose that we get right? And so naturally, naturally, yeah, right. But that can do its end, even without candies, it's still gonna present at low amounts, we know it's produced. It's one. So I talked about cosmic radiation. And so when you have cosmic rays from space, interacting with elements within our atmosphere, so tritium is actually one that can be produced that way. So it's going to be a low amount in water that we drink and things and so it's, it's pretty low, though, in terms of our background radiation dose, it's pretty insignificant compared to potassium 40, or in particular, radon. So you know, Potassium 40 is a, like you said, a beta decay, different energy of beta, we just have a lot more potassium that we're exposed to in food and things like that. So you know, it's it's kind of an analogous type of radiation exposure. But we're exposed to a lot more just from a potassium than we are from tritium.


Chris Keefer  33:19  

And, you know, the numbers are just like, astounding to me in terms of like, how many decays you said, like 150, atomic decays per like meters, cubic meter cubic meter of air? Do you have any given anomaly ambushing you off the hop here, but like in terms of potassium decays in the body? Do you have any stats on that? Like,


Chris Thome  33:36  

yeah, I'll think back to my powers, but it's on the order of a couple of 1000. Right. So yeah, so when we talk about back rails, it's a decay per second, right? So with potassium 40, and carbon 14 is another one, too. Yeah. So we have both of them at pretty high levels in our bodies. And so it's on the order of several 1000 back grills of each isotope. So in one second, you've got a couple of 1000 Atoms of potassium 40 decaying within your body right now, getting that data and that gamma radiation,


Chris Keefer  34:07  

frying or DNA and then getting repaired? Exactly. Good. And one last thing, because this is kind of hinted at this before, but the the repair mechanism we have for DNA, most of the damage has been driven by oxygen, essentially. And like enough, smaller, much smaller fraction is being driven by radiation. But But is it it's the same sort of DNA repair mechanism that we use for both Is that


Chris Thome  34:29  

Yeah, that's correct. So radiation works, mainly through kind of indirect mechanisms. And so the actual photon of radiation you're gonna get exposed to doesn't necessarily directly damage your DNA. It mainly works through the production of free radicals. So things like hydroxyl radicals that are these really short lived but really reactive species within your within your cells. And so that's where a lot of your DNA damage comes from. But normal cellular metabolism, cellular respiration also produces those those free radicals


Chris Keefer  34:56  

unless you're on a special diet. Right.


Chris Thome  34:59  

Thank you. Well, you're you're still Yeah, well, you can have antioxidant diets, which just give you more levels of the things that can remove those those reactive species. But as long as you're breathing oxygen, you're still producing free radicals. So yeah, same same type of DNA damage that you're gonna get same mechanism by which ourselves repair them.


Chris Keefer  35:20  

Awesome. Okay, so again, this interview is supposed to be like five minutes, but this is totally fascinating conversation. Kritis talk as long as you want mazing I will have you back for sure. Great. Thank you again for coming on. I look forward to visit I'm gonna hopefully visit


Chris Thome  35:33  

Yeah. Right now still, I think for sure for tours. But as soon as that opens up again, yeah, we'll get you up and beautiful. We'll do can do all just some shots down there. And yeah, yeah, they love that. Looking forward to it. All right. Thanks again.


Chris Keefer  35:45  

Yeah. If you enjoyed the podcast, please make sure to subscribe, like and review us on your podcast platform of choice. Until next time, guys.



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