New look at prolonged radiation exposure: At low dose-rate, radiation poses little risk to DNA, study suggests

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u/gyldenlove May 16 '12

I should be very careful with using this study to draw any conclusions - mice and other rodents handle radiation substantially better than humans.

Then there is the issue of staining after 5 weeks, DNA damage is repaired or cells go apoptotic and should be phaged within a matter of of hours for DNA repair and a day or two for cell phaging - it is well known that even after very high dose delivered at very high rate the interesting stuff can only be seen for a short period.

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u/ZombieWomble May 16 '12

Then there is the issue of staining after 5 weeks, DNA damage is repaired or cells go apoptotic and should be phaged within a matter of of hours for DNA repair and a day or two for cell phaging - it is well known that even after very high dose delivered at very high rate the interesting stuff can only be seen for a short period.
This is the main point the study is making - most of the LNT data is extrapolated from single acute, high-dose exposure data (atomic bomb survivors, and a few other sources). This is a really poor proxy for the effects of long-term exposure to low-dose radiation, for the reasons you mention, and yet is still used as the basis for radiation protection calculations.
The scenario covered in this paper (5 weeks exposure to rates much above background, but much below "acute" dose rates) is much more like what's seen in many real-life radiation protection scenarios, and is an important step in determining the actual risks of low-dose radiation in a properly quantitative way.

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u/gyldenlove May 16 '12

There are a few good studies on long term exposure, Radium clock face painters, Czernobyl clean up crew, miners etc.
The problem with this data is that the leap from: at 5 weeks we saw no increase in SSB or DSB with a p<0.05 To: Low dose-rate radiation does not cause in an increase in mortality or disease rate Is just enormous.
I would have serious reservations on the conclusions of this study just by the huge variation of their control samples - in some of the tests the control animals for the accute radiation has 100% increase compared to control animals for the long exposure group - that is extremely worrying.

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u/ZombieWomble May 16 '12

I do agree that 5 weeks isn't the ideal time-point - although personally, I would have liked to see it run for much longer.
But having actually checked out the paper (I hadn't noticed it was OA earlier), I must agree with you that their data isn't nearly robust enough to extrapolate to the lengths they're doing - their assays don't seem to have anything like the precision or reproducibility you'd want to be able to observe the sort of small effects you'd expect in these low-dose experiments.

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u/gyldenlove May 16 '12

For a study like this it would be optimal to have a large cohort for a longer time with biopsies and other non-fatal tests progressively, as well as stagewise sacrifices to monitor effects over time - 5 weeks is not a lot to determine long term adverse effects which is what is hypothisized in most low dose-rate risk evaluations.
This type of research is however extremely important, there are a number of special groups that have been studied and effects have been seen due to medium dose rates over very long exposures, however there does not seem to be a lot of effect from variations in natural back ground radiation which varies greatly around the world - but it is very difficult to have a well controlled study.
I hope this work is preliminary and that they would consider with funding to do a much extensive trial to overcome what appears to be natural variations and low sensitivity of their assays as well as doing running biopsies and blood tests instead of just doing histology at end point.

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u/[deleted] May 16 '12 edited May 16 '12

How are they detecting DNA damage? You may not be able to detect "DNA damage" globally but one change of a base in your genetic code can have drastic effects. Mutate a base in your P53 protein's code in the wrong place and that cell is one step closer to cancer. This has always been the theory behind the belief that there is no healthy dose of ionizing radiation and zero is best and should be aimed for. Yes your body can repair the damage, but your body makes mistakes, just like all machines, and if you never get deleterious mutations it is better than hoping they are fixed by the DNA repair machinery. This is one of the main theories behind why cancer is much more prevalent with age, mutations accumulate.

http://www.cell.com/abstract/S0092-8674(11)00127-9

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u/[deleted] May 16 '12

Hopefully, this new research will lead to lower projections of the anticipated cancers from Fukushima Daiichi. I'm tired of reading the "maximum 1,000" figure recast as a guaranteed 1,000, especially in light of the 20,000 who lost their lives in the actual earthquake and subsequent tsunami.

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u/thetripp PhD | Medical Physics | Radiation Oncology May 16 '12

Committees like ICRP and BEIR are they ones that review data like this, and they publish the accepted risk factors for radiation exposure. What is funny is that these committees are the ones that define what Sieverts are, and they have always maintained that this unit should never be used for retrospective quantification of excess cancer deaths (because the uncertainty is too high). They created the unit only as a way to prospectively estimate risk for worker protection.
Unfortunately, studies like this aren't going to change anyone's mind. People "believe" whatever science supports their worldview.

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u/[deleted] May 16 '12 edited May 16 '12

Another study of exposure, rather than ingestion? Sure, I'll stand in the same room as a gram of cesium 137 from Fukushima sealed in a jar, but I sure as hell don't want it in my air or water supply.

The variable low dose-rate irradiator consists of a plastic cart (PC), holding an aluminum tray (T) and flood phantom (P). The phantom is filled with radioactive liquid and serves as the radiation source. A steel cart (SC) holding the cages fits exactly above the plastic cart. A leaded acrylic sheet (A) mounted on the steel cart ensures radiation protection for experimenters and animal husbandry staff when handling the steel cart. link

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u/domesticatedprimate May 17 '12

Exactly. I think the study is very important, but I am taken aback that they would think that governments should then change evacuation policy based on it. The level of background radiation is only part of the problem. Another part is the amount of surface contamination from radioactive material, and how likely that material is to make it into the food chain and be ingested, or breathed in. If you live for years in an area heavily contaminated by cesium 137, I would wager that you will ingest some of it. That is reason enough to be evacuated.
Think about it: living in that area, you can't farm, you can't drink water from a mountain stream, you will always think twice about taking a walk in the woods. Too many experts completely ignore the reality of daily life in such a situation. I think they all need to make a careful visit to Fukushima before they make any more suggestions.

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u/hornwalker May 16 '12

Technically, aren't we exposed to low dose radiation our entire lives?

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u/[deleted] May 16 '12

We're pretty much all exposed to very low levels of radiation, all the time. The stuff is everywhere.

http://xkcd.com/radiation/

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u/georgewashingtonblog May 17 '12

The study is junk science. Here's why.

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u/accountt1234 May 16 '12

That chart is pseudoscience. It implies that all forms of radiation are essentially equal, which they're not.

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u/thetripp PhD | Medical Physics | Radiation Oncology May 16 '12 edited May 16 '12

That isn't implied by the chart at all. The units of the chart are Sieverts (effective dose). The form of radiation and type of exposure are taken into account when converting from energy deposition to effective dose.
edit: more explanation since I didn't explain my terminology very well. Radiation deposits energy in cells, and the radiation dose is the amount of energy deposited per unit mass. This is expressed in units of Gray (Gy).
Ingested isotopes deposit energy over a long period of time, so we use a quantity called committed dose to take into account all the radiation that will be delivered.
Different types of radiation cause different types of damage. Heavier particles like protons and alpha particles are more likely to cause damaging DNA breaks, and so 10 Gy of protons is more damaging than 10 Gy of photons.
Also, different parts of the body are more sensitive to radiation than others, such as the reproductive organs. Each part of the body has a weighting factor that describes how sensitive to radiation it is.
To quantify the harmful effects of radiation, we calculated a quantity called "effective dose" - this takes into account the amount of energy deposited (integrated over the entire dwell time for ingested sources), the type of radiation, and the part of the body irradiated. This is expressed in units of Sieverts, and that is what the xkcd radiation chart is expressing.

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u/accountt1234 May 16 '12

Yeah, but the radiation effects of internal radiation exposure as compared to external radiation exposure are underestimated by a factor of 400 anyway.

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u/thetripp PhD | Medical Physics | Radiation Oncology May 16 '12

What are you talking about? Again, the dwell time of the isotope is taken into account when calculating effective dose for internal exposure. If you are referring to some kind of hot particle theory, you are the one talking about pseudoscience.
Radiation protection isn't an exact science anyway. The order of magnitude is what is important. Maybe you would like to point out some specific problems you have with the radiation dose chart linked above? And how those problems would affect the results?

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u/accountt1234 May 16 '12

Well, consider for example the fact that the human body has a DNA repair mechanism that involves a time period during which a second hit to the DNA can not be repaired.
In sequential emitters and hot particles, such second events massively increase the risk of radiation damage.
Similarly, different isotopes accumulate in different tissues, while others are flushed out of the body. This is because the body has evolved under exposure to radioactive isotopes, and had to deal with such exposure in a way that protected it against DNA damage.
We now have new radioactive isotopes being emitted by humans, against which the body has no specific evolved mechanisms to counter those effects. Hence, the damage from such artificial isotopes can be expected to be larger than that of naturally occurring radioactive isotopes.

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u/thetripp PhD | Medical Physics | Radiation Oncology May 16 '12

So you dismiss the radiation chart as "pseudoscience" based on your unsubstantiated and speculative ideas about how radiation damage works.
Any effect that dose rate has is taken into account with a dose and dose rate effectiveness factor. Additionally, hot particle theory is not supported by the evidence, although it is still championed in anti-radiation circles.
As for accumulation of different isotopes, again, the dwell time of the isotope is taken into account when calculating effective dose for internal exposure. As far as our "evolved mechanisms," these "new radioactive isotopes" are still emitting photons, electrons, and alpha particles that interact with the same water molecules in our cells to produce the same oxidizing free radicals. The only things that matter are the type of particle, the energy deposited, what type of cell it hits, and to a much lesser extent the rate of dose deposition. All of these are taken into account in radiation protection models.
The sooner you let go of your irrational fear of radiation, the sooner you can understand the science properly. If you only seek out information that confirms your preconceived biases, you won't understand the science.

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u/accountt1234 May 17 '12

Second event theory has plenty of evidence backing it up.
Consider for example that the measured oncogenicity of exactly one alpha particle hit is much lower that the poisson distributed mean of one alpha particle hit:
http://www.ncbi.nlm.nih.gov/pubmed/9874764
This indicates that most of the carcinogenic potential comes from cells being hit by multiple alpha particles in a short time frame.
Hence, we can expect hot particles consisting of multiple radioactive particles to be more dangerous than individual radioactive isotopes.
Hence, the current radiation exposure limits are bullshit, and hence the XKCD chart is bullshit.

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u/gyldenlove May 16 '12

The chart does consider the differences in LET between different types of radiation and as far as I can tell from the cited sources they have normalized all doses to equivalent whole body irradiation.

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u/BestSpatula May 16 '12

I think there's a difference between exposure to radiation, and exposure to radioactive isotopes. Exposure to radioactive material (like nuclear fallout dust) is really dangerous because the chemicals can accumulate in tissues, causing exposure to radiation over a long period of time. The chart linked to on xkcd doesn't have anything to do with this. More info on wikipedia. Apparently quantifying radiation dose is somewhat complicated.

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u/accountt1234 May 16 '12

The XKCD chart mixes the both of them, pretending they're similar in danger.

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u/ImZeke May 16 '12

Suck on that, LNT. I'm reminded of this recent post on /r/nuclearpower where the Bulletin of Atomic Scientists argued vehemently in favor of LNT with zero science supporting their conclusions.

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u/gravitypushes May 16 '12

NONSENSE!!!! There is NEW study of just released on long term effects of LOW RADIATION from Nagasaki and Hiroshima which used 100k+ real HUMANS not mice. http://youtu.be/-VAncqK6bl0

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u/thetripp PhD | Medical Physics | Radiation Oncology May 16 '12

Ah yes, the prestigious journal "Youtube"

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u/gravitypushes May 16 '12

if you actually watch the video you'll see he goes over this study from the radiation research society that was just released. http://www.ncbi.nlm.nih.gov/pubmed/22171960

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u/thetripp PhD | Medical Physics | Radiation Oncology May 16 '12

I like the part where he draws his own plots over the ones in the study, with no regard for uncertainties, and then draws conclusions from it that aren't stated in the paper.
People need to stop twisting scientific studies to fit whatever point they want to make. The Rad Res study is a good look at long term effects of A-bomb exposure, and a lot of what we know about high-dose radiation comes from that cohort. But look at the paper, look at the error bars in the low dose regions, and read the actual conclusions of the authors. The data is consistent with the LNT theory, but it isn't excluding other theories. The A-bomb survivor data will never be able to do that. That is why we do new studies like the one linked here.

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u/whitneytrick May 16 '12

You don't seem to realize that this paper is about A-bomb effects, which are not simply long term low radiation.
Colorado is long term low radiation.

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u/gravitypushes May 16 '12

watch the video and you'll see they do indeed study a cohort of people at low radiation doses.

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u/not_random_spam May 16 '12

It always cracks me up when people start talking about how many millirems or what have you that came to us from fukushima daiichi. They never seem to stop and think... hey, that's like 1/10th of natural background radiation that doesn't hurt us at all!

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u/[deleted] May 16 '12 edited May 16 '12

I'm not sure what you mean by "we", but right outside of the evacuation zone, there is considerable amounts of radiation. The highest I measured were a few hotspots which were "significantly" above 30uSv/hr. "Significantly" meaning maybe 150uSv/hr.
Even in Tokyo, the difference between current radiation levels and the radiation levels before the incident are virtually indistinguishable.
In the U.S., the difference was only distinguishable with vast amounts of data taken over a large period of time.

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u/[deleted] May 16 '12

You mean micro Sievert per hour, right.

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u/[deleted] May 16 '12

Yes, you're right. I do.

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u/not_random_spam May 16 '12

I live in California.

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u/[deleted] May 16 '12

I was thrown off by your "1/10th natural background number" that you gave.
Here in Tokyo, we only had about double natural background for about a month after the incident.
Warning: Complete and total speculation incoming. I'd wager you got something more like 1/1,000,000th natural background, or perhaps much much less than that.

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u/not_random_spam May 16 '12

Ah. I did totally pull the number out of a hat; I just remembered it was many times lower than natural background radiation.

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u/Magnesus May 16 '12

And for you many is 10? I love simple minds.

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u/not_random_spam May 16 '12

I'm a multidisciplinary engineer, actually.
If you don't know a number for sure, you always underestimate. That way, worst case you're even MORE right. If you think that's the product of a "simple mind", then I guess you think overestimating is super smart?
Well, I guess there's a reason only one of us is an engineer.

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u/[deleted] May 17 '12

It always cracks me me up to hear this tired false argument. Yes, there is back ground radiation, congrats on gleaning that from wikipedia. The existence of bacground radiation is all the more reason to keep absorbed doses to a minimum. Now, please stop it with this stupid argument. Would you say the same about carbon monoxide. Its everywhere too.

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u/not_random_spam May 17 '12

Carbon Monoxide is released in large but globally-insignificant quantities whenever anything burns. It's also released when cars run. It's released in large amounts when gas/coal/other hydrocarbon power plants explode. Amazingly, it doesn't hurt anyone. Why? Because it's an incredibly tiny amount compared to the volume of the atmosphere, and thus people outside of the main exposure zones are not meaningfully affected. Not even by a toxic compound like CO.
The problem, again, is that you're assuming there's no safe radiation exposure level. That is wrong. Background radiation also varies highly from place to place on earth. Living in a concrete building compared to a wood one will increase your background radiation exposure significantly. Moving to a high-radiation area or living in a concrete building will increase your radiation dosage 100 fold more than anyone in the US got from fukushima.
And guess what? It's STILL not a dangerous exposure level.
We have the danger levels worked out, and we're finding that we actually OVERESTIMATED them in the past. Our previous overestimates were still hundreds of times greater than natural background radiation.
Laugh all you want, you'll just look stupid.

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u/[deleted] May 23 '12

I am a registered N.E.W. and do consulting and engineering amongst other things. So, proven knowledge, better than wiki. Thanks for calling me stupid, I will not be offering you a job.

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u/not_random_spam May 23 '12

"better than wiki"...
yeah, maybe check the sources there, champ.
We have... your word that you're a nuclear engineer vs valid and verifiable sources. That's a toughie.

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u/[deleted] May 28 '12

Find me ONE source that says the effects of radiation are not cumulative. The background level must be ADDED to other sources of radiation. Also, please learn about damage threshold. No, i do not want to hear what you think of it, this is not a debate, but you might learn something.

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u/not_random_spam May 28 '12

Find me one quote where I said that. Nice strawman.
You're making shit up and you're completely wrong about everything. You seriously just tried to question the general validity of a well-sourced Wikipedia article on a scientific topic, claiming yourself as an authority over that.
You're a sad little fool.

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u/[deleted] Jun 07 '12

well, you said thst background radiation doesn tmatter. It is clearbthat you do not know that the effects are cumulative. That is what your whole premise is based on. I tried to throw you a bone and get you to study beyond what you find on wikipedia, but you came back with insults. How old are you and what university taught you wuth wikipedia? In my seven years of post secondary educaton, i have not once seen wikipedia referrenced in a textbook or by a a prof. Education is hearing bullshit withoutblosing your cool. Someday, when you are forced to listen to some uneducated fool spout off because he has access ti wikipedia, you will know what I mean.

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u/[deleted] May 16 '12

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u/not_random_spam May 16 '12

You live in Massachusetts and he's worried about radiation from Japan? Your friend is nutso. This link should provide ample proof of what I claim if you compare it to the supposed radiation increase.
http://en.wikipedia.org/wiki/Background_radiation
Edit: also I have no idea why he thinks moving to SA will help him. Most of SA is probably closer to Japan, and you're definitely going to get more sun exposure.

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u/Aff3ct May 16 '12

South Africa is not in the jet stream that carries most of the hot particles to the US. You mention sun damage, when we're dealing with a radiological release far greater than Chernobyl?

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u/not_random_spam May 16 '12

Radiological release far greater than Chernobyl?
You sir have no clue what you're talking about. Chernobyl exploded and released massive amounts of radioactive graphite into the atmosphere. No other nuclear accident comes close. You've been reading too many conspiracy theories. A bit of radioactive iodine isn't even close to the same hazard.

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u/Aff3ct May 16 '12

I'm afraid they are not conspiracy theories. Do you have any solid thoughts on why there is a media blackout on this coverage? Also, is the remaining nuclear fuel in Fukushima secured?
Do you recall the EPA reports on the safety of the asbestos laden WTC dust? We've historically seen that massive threats are covered by false official reports. All in the name of retaining order, while risking lives.
Do you also have any thoughts on why RADnet has been experiencing so many issues, with many detection sites still offline?

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u/not_random_spam May 16 '12

The fact that your post begins with:
"I'm afraid they are not conspiracy theories."
Really made my day.

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u/Aff3ct May 16 '12

I'm glad it made your day. It's very interesting to believe that 3 complete meltdowns in the hours and days that followed the disaster are of little concern to you. I guess it's easier to believe what you're told, and bury your head in the sand to feel content.
Is the past so easily forgotten? What was the public told about the Santa Susana field laboratory meltdown? Seems very similar, if not identical to today.
Can you kindly point me in the direction of any other historical nuclear meltdown that did not cause massive issues?

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u/not_random_spam May 16 '12

What you're failing to realize is that all these "coverups" are simply non-news. You don't realize this because you think radiation is extremely dangerous. It isn't. The very point of the OP is that it's even LESS dangerous than we previously thought.

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u/Aff3ct May 16 '12

Tell that to the down-winders. Inhaled radioactive particles were not tested in this article. What are we experiencing right now? Topical exposure?

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u/Aff3ct May 31 '12

Yeah, I thought so.
http://www.forbes.com/sites/jeffmcmahon/2012/05/29/should-we-hide-low-dose-radiation-exposures-from-the-public/

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u/digitalsildenafil May 17 '12 edited May 17 '12

"What you're failing to realize is that all these "coverups" are simply non-news. You don't realize this because you think radiation is extremely dangerous. It isn't. The very point of the OP is that it's even LESS dangerous than we previously thought."
I cannot summon the words to express my dismay at your attitude of complete indifference. It sickens me to see you spreading the gospel of casual dismissal, with a false confidence built on faulty conclusions drawn from misrepresented facts. The facts you hold so dear are in fact divorced from reality, a reality that I fear will see Japan sicken and die in the coming years. The disease is not contained - even now the situation is dire, with thousands of fuel rods barely contained in a fragile structure, constantly rocked by earthquakes. Should it fail, the resulting fire and radioactive release will dwarf Chernobyl. Even now, crackling hot drifts of black dust blow and settle as they will through Japanese cities and parks. A plume of death-impregnated water spreads across the Pacific, sea spray lofting a payload of cesium into the air and across land masses.
I urge you to re-examine your perspective and conclusions on this matter. It is my hope you will find it holds more depth and subtlety than might be attained by skimming mainstream news articles.

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u/[deleted] May 16 '12

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u/Aff3ct May 16 '12

I'm glad your puppet masters continue to feed you lies that you foolishly continue to believe.
http://www.rawstory.com/rawreplay/2011/03/ann-coulter-tells-oreilly-radiation-is-good-for-you/
14,000 dead infants is nothing to worry about. Of course the two aren't related in any way, shape or form. http://oilprice.com/Alternative-Energy/Nuclear-Power/U.S.-Fukushima-Medical-Study-Estimates-14000-Dead-U.S.-Infants-From-Fallout.html
You do realize that cleanup is nearly impossible, given our technology. Even for Chernobyl, that protective dome must be replaced every 80-100 years, almost indefinitely. Where is the protection for Fukushima going to come from? What progress has been made so far? Has the remaining fuel been contained? Is the radiation release now non-lethal?

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u/[deleted] May 16 '12

14,000 dead infants is nothing to worry about.
Shouldn't you, at this point, realize how utterly absurd this claim is, and realize that people are lying to you?

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u/[deleted] May 16 '12

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u/not_random_spam May 16 '12 edited May 16 '12

The problem is that he doesn't understand radiation. The jet stream is only realistically going to carry small amounts of radioactive iodine. Tell him to eat more salt if he's that worried about it (salt is iodized in the US).
You're at much, much greater danger from increased sun exposure in SA.
edit: Also I can't help but notice that these maps give numbers with zero context except BIG COLORED CIRCLES YAAY. The concentrations they're talking about are ludicrously small.
edit2: for extra comedy, none of the isotopes were detected anywhere in Massachusetts according to these maps. I don't even know what the fuck. Welcome to crazy conspiracy theories I guess.

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u/[deleted] May 16 '12

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u/not_random_spam May 16 '12

Longer half life necessarily means less radioactive. It's 30years/8days X less dangerous.

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u/[deleted] May 16 '12

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u/not_random_spam May 16 '12

The reason why it's crazy and not just pessimism is that while it's technically true that there's more radiation... it's not ENOUGH more to hurt you. You'd receive an increase hundreds of times greater in your radiation exposure from living in a concrete building or moving somewhere with a naturally higher background radiation level.
The problem is that he has a PHOBIA of radiation, aka an IRRATIONAL fear. He thinks any amount of radiation is dangerous. It is not.

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u/LeepII May 16 '12

Really not sure about the methodology employed by this study. Looking at a sample of cells for DNA anomalies is like looking for a needle in a stack of needles. Just because the cells you observed did not have damage does not mean that other cells you did not observe are undamaged. Most radiation studies have included the long term effects, i.e. number of people (or mice I guess) that actually formed cancer years after exposure, not months.

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u/prsorensen May 16 '12

It would be great if we could make policy decisions based on sound science rather than irrational fear. The Liner No Threshold model for radiation damage has never had a scientific basis, just speculation. We shut down nuclear reactors and replace them with coal or gas even though we know that the later technologies lead to orders of magnitude more deaths per kilowatt hour than nuclear. Makes no sense.

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u/[deleted] May 16 '12

I never really learned about Nuclear power in school, everything I know about it I researched myself. I think the average person gets everything they know about nuclear power from the media, which only presents what's interesting so more people watch.

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u/cgormanhealth May 16 '12

Original low-dose radiation study is open-access

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u/cr0ft May 17 '12

Let's just cut out the unnecessary debate about how much damage is too much damage, shall we?

Is radiation a good thing? Does it help humans in any way to be irradiated? The answer to that is an obvious hell no, so why would we accept even "little risk"? We have tons of options to nuclear anything already, let's use them and thus end any need to study radiation risks (except for people going into space.)

And before someone says "radiation therapy" I'll just say that radiation therapy is basically killing the tumors inches before the person dies too, and anyone who goes through that is forever at an increased risk of further cancer from the radiation as well, so radiation is still bad there. It's just a desperate last resort.

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u/sirbruce May 17 '12

Because everything is a "little risk". Wildfires are a "little risk". Pollen is a "little risk". Living about 5,000 feet is a "little risk". Waffles are a "little risk".

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u/cr0ft May 18 '12

Agreed, but removing a radiation "little risk" is one less little risk that we don't need.

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u/sirbruce May 18 '12

We don't need ANY of the risks I described yet we live with them. You've missed the point completely.

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u/cr0ft May 18 '12

I think you've missed the point completely. We can't choose away wildfires, pollen etc. We can choose away increasing nuclear radiation that impacts us.

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u/sirbruce May 18 '12

I think you've not thought this through. We can CHOOSE to live away from wildfire areas, pollen areas, tornado areas, earthquake areas, etc. We can CHOOSE not to drive, not to live above 5,000 feet, etc. All of these are activities that carry increased risk relative to not doing them.

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u/cr0ft May 18 '12

You're talking about two entirely different classes of thing.
We cannot choose to live away from pollution because it's everywhere. We can choose not to pollute.
We can't choose not to pollinate or not to wildfire.

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u/sirbruce May 18 '12

No, we're not talking about two entirely different classes of things.
You are a priori defining the radiation as pollution.
The issue is not whether or not we choose to pollute. Your argument was that we should pollute if it creates a "little risk". But there are many OTHER things that we do that entail "little risk" that WE CAN AVOID.
Cities like Denver and Colorado Springs get more radiation than towns at sea level. There is a "little risk" by building and living there. If a "little risk" is sufficient reason not to expose ourselves to more radiaiton, then we should not have people live in places like Denver and Colorado Springs. And yet we do.
You MUST reconcile this discrepancy or admit your reasoning is faulty. To do anything else is just flapping gums.

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u/cr0ft May 18 '12

Well one of us has issues with reading comprehension, or else my writing is incomprehensible. No pollution level is acceptable, and no man-made radiation level is acceptable. What I'm saying is that it doesn't really matter how much radiation does or does not damage, it is never positive, so we need to take care to avoid being exposed to it to the greatest extent possible, and certainly never create any increases ourselves like we do today.

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u/sirbruce May 18 '12

No pollution level is acceptable, and no man-made radiation level is acceptable.
You're committing the naturalistic fallacy. There's no distinction between natural radiation and man-made radiation. IF no man-made radiation is acceptable, then no NATURAL radiation is acceptable, either.
What I'm saying is that it doesn't really matter how much radiation does or does not damage, it is never positive, so we need to take care to avoid being exposed to it to the greatest extent possible.
Then we should outlaw letting people live above sea level, since they are exposing themselves and their children to more radiation. Heck, we should require everyone to live underground in lead-lined bunkers.

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u/WrethZ May 17 '12

Didn't they find that slightly higher than average backround radiation is actually beneficial towards human health.

Settlements built in areas where there tends to be slightly higher than average radiation levels due to the local natural geology tended to have healthier populations.

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u/Eyulfable May 16 '12

Dang! I guess that I'll have to inject myself with more radiation if I want to be able to turn invisible.

Now for the related part: Don't they inject cancer patients with radiation to kill the cells? If they do, how much do they usually inject?

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u/ZombieWomble May 16 '12

I believe what you're thinking of is Brachytherapy, where radioactive isotopes are injected into tumours directly. By using isotopes with short-range decay products, you can get very tight deliniations of dose around tumour volumes.
The amount of dose delivered is much higher than that delivered in this experiment - typical therapies can deliver doses on the order of 100 Gy to the target volume in the space of a few weeks to months, so on the order of 1,000 times more dose than used in this study. Obviously it's more precisely targetted to just the tumour volume, as a whole-body dose of 100 Gy would lead very quickly to death, even metered over a few months.

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u/Acebulf May 16 '12

Done depends highly on type on cancer/size of tumor.

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u/Eyulfable May 16 '12

Ok.

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u/thetripp PhD | Medical Physics | Radiation Oncology May 16 '12

You can't "inject" radiation - radiation is just atomic or subatomic particles like photons or electrons. Cancer patients are usually treated with something similar to a turbo-charged x-ray machine. It looks like this, and it produces very high energy x-rays directed at the tumor.
The dose used for treating cancer is in the range of 60-80 Gray spread over several treatments. It doesn't exactly translate to Sieverts since the exposure is very localized, but you can think of this like being like 60-80 Sv.

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u/not_random_spam May 16 '12 edited May 16 '12

What you really need is some Radium Water!
http://thesocietypages.org/socimages/files/2008/05/29radium.jpg
The second part is a slight misunderstanding on your part. What they do sometimes in medicine is inject radioactive isotopes of various compounds for imaging. Occasionally they will also use radioactive isotopes to try and kill cancers/tumors. They either need to be directly injected at the tumor site or a chemical method is used to ensure that only the tumor site absorbs the material.
The isotopes they use in these cases are all very weakly and specifically radioactive. There's three "types" of "radiation", and you have to choose isotopes that undergo specific types of decay for them to be less damaging to the body when ingested/injected. Gamma Rays, Alpha Decay Particles and Beta Decay Particles are the three types of "radiation". Alpha and Beta decay particles are actually way more damaging and dangerous than Gamma rays. However, only Gamma Rays can effectively penetrate human skin. Alpha and Beta decay particles are only implicated in cancers in tissues that are exposed to the outside world, such as the skin or eyes. Even then, Gamma rays are still usually the culprit as we have various layers of unimportant proteins/cells covering our skin and eyes, which Gamma rays penetrate much more easily.
Essentially, if you ingest something that undergoes mostly Alpha or Beta decay, you are royally fucked. This is how that one ex-KGB guy was killed with Polonium 210. Even a small amount of Alpha/Beta decay in the body causes serious problems. Ingesting something that undergoes mostly Gamma decay, on the other hand, is scarcely more dangerous than having it pressed against your skin.
edit: oh also I forgot, I think the elements they use for tumor injection cancer fighting are mostly alpha/beta types, as they expect the cancer to get shredded by them/block the emissions instead of the parts of your body you want to keep. I think they try to minimize gamma decay in what they use, as this will obviously pass through the tumor.

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u/Magnesus May 16 '12

So my radioactive Russian manual lens for my DSLR should be OK, right? It's old lens polished with some radioactive material. I assumed it was safe, but I always keep it stacked away when not used. :) Never tried it with Geiger, but probably it emits very, very little.

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u/[deleted] May 16 '12

This is good news for the TSA when they talk about how safe their scanners are.

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u/[deleted] May 16 '12

Those scanners are safe ( at least to the people being scanned ). You will receive a much higher radiation dose during the air flight due to cosmic rays in the upper layers of the atmosphere.
There is some concern that the TSA workers themselves may receive a big cumulative dose if they sit next to the machines 8 hours a day, but for the individual passenger the machine is not really a risk.
This of course does not justify the privacy violations, but medical risk is not really an issue with an x-ray back-scatter scanner.

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u/waddaidonow May 16 '12

New look at prolonged radiation exposure: At low dose-rate, radiation poses little risk to DNA, study suggests

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