I have no doubt that patients are getting exposed to more radiation via imaging than they need to.
However, every decision in medicine is (or should be) a risk-vs-benefit analysis. Cancer is not the only thing you can die from. If you suffer a head injury and end up in the ER and get a CT scan, you may increase your long-term risk of cancer, but you are also drastically reducing the risk of dying from a brain hemorrhage that couldn't be identified by any other method.
Of course, no one would dispute ordering a CT for a trauma patient if the presentation warrants.
But the article was talking about the increase in CT usage over the past 20 years. That's largely been driven (in the US) by misaligned incentives that reimburse procedures at much higher rates that clinical decision making. Put simply, the person who owns the CT machine makes much more than the doctor who interprets the results. And so we have had a blossoming of imaging centers, and CT machines have moved into outpatient cardiology and even family care practices.
One of the major goals of Obamacare is addressing these misaligned incentives and shifting to a model where providers are paid to keep people healthy (outcome driven) rather than on volume (fee for service).
Another issue has been the difficulty of sharing/accessing existing imaging data, so tests are just repeated to save time (rather that save cost or adequately balance safety). Our long, painful journey to electronic record standardization should also help with that.
The doctors are doing a risk/benefit analysis: the risk is to the patient and the benefit is to their wallets. It's a no brainer.
Everyone likes to shit on lawyers, but US doctors routinely take on, and fail to disclose, conflicts of interest that would get a lawyer disbarred in a heartbeat.
Unfortunately, there is another external factor playing into the risk/benefit analysis that I haven't seen mentioned hear yet - the threat of legal action. With such low barriers to filing a malpractice lawsuit and such high payouts for "victims" and devastating effects for doctors, CT scans are often ordered for the sole purpose of mitigating legal risks.
For example - someone comes into the ER with simply a headache. On its own this should not warrant a CT scan. But if a doctor does not order one, and that patient leaves and eventually comes back with a brain tumor (extremely small odds, but not zero), then the following malpractice suit would almost certainly result in a plaintiff victory and the end of a doctor's career.
Malpractice is a real thing and real victims deserve their due. But lawyer attack ads and no limits on "pain and suffering" payouts (often multi-millions) I believe are a critical part of the difficult healthcare situation in America that continues to go unaddressed.
Except an MRI scan is just as good, but doesn't expose you to radiation. The problem is CT scans are slightly cheaper, so the insurance companies won't pay for an MRI.
>A single CT scan exposes a patient to the amount of radiation that epidemiologic evidence shows can be cancer-causing
That does not look right to me. A single CT scan is 2-7 millisieverts, and exposures under 13 can not be linked to health effects - look for UNSCEAR in http://en.m.wikipedia.org/wiki/Sievert
If you do the math by ICRP formulae, you end up with increase chance of cancer of 1 in 2600 over the next 20 years from a single 7ms CT scan today. This compares favorably with "natural" risk that is 1 in 10 without any extra exposure above background radiation.
Now if you do a scan every year for the next 20 years your chances go up to 1 in 130. So there is something to worry about, but article overstates the cause.
The distribution of these cases is likely to skew towards the Elderly and over 50 demographic. I'd be curious to see the impact of this on the analysis.
Let's say the average person does not get a CT scan every year for 20 years, but rather gets 5 scans over their lifetime.
Those scans may detect an early stage of cancer, therefore saving the persons life.
They're risk of dying from cancer is approximately 20.2%. I suggest with the CT scan, their still coming out on top.
Incidentally, this is exactly why I included the numbers - so you can check them, and why I don't like the headline article - no numbers and no references, so there is nothing to check, only vaguely scary claims.
Newer machines are at least reducing the radiation. This is due to better compute power and to better sensors (essentially a mineral which converts x-rays into flashes of light which then get captured by a photodiode).
It's been huge in dental x-rays, going from film to CR/DR (although dental isn't huge, it's routine, and involves a large patient population including kids.)
We probably will be <5 mSv for whole-body pretty soon. Ultimately there's no reason it can't be well under 1 mSv.
Fluoroscopy on the other hand is easily 50 mSv/min and multi-hour procedures (!!!). People get acute effects from that.
A full-body CT scan results in 12 mSv; a mammogram 0.13 mSv—a hundred times less. The risks from these procedures, according to AAPM, are too low to have been determined reliably, and may be "nonexistent."
Looks like this debate has been going on for a while now.
Here[1] is a very recent study from Austrialia which concludes CT scans during childhood and adolescent increase the risk of cancer and should be avoided where possible.
>If you do the math by ICRP formulae, you end up with increase chance of cancer of 1 in 2600 over the next 20 years from a single 7ms CT scan today. This compares favorably with "natural" risk that is 1 in 10 without any extra exposure above background radiation.
But that is a meaningless comparison. The doctor should be comparing this additional risk, to the benefit of the scan.
The "natural" risk of developing cancer is totally irrelevant to the cost-benefit analysis.
Because we operate in likelihood ratios, the unexposed risk is important so the risk can be computed (at least, in theory; in practice, people go more by indication than by formal risk prob/benefit prob).
If I want to know whether to do a CT scan, the only relevant fact is the increase in probability (in an absolute sense) of cancer that it causes.
It seems like either you, or the entire field of medicine, is obfuscating this basic fact using some field-specific concepts.
EDIT: It seems like you are referring to relative risk (http://en.wikipedia.org/wiki/Relative_risk). But as I said, there is no reason that relative risk should be considered in this case.
I wonder though if there should be a cutoff somewhere, below which you stop caring? I used background cancer rates as an anchor to judge if the cutoff has been reached, without getting specific about benefits of treatment in each particular case. Would you suggest another cutoff level that is broadly applicable?
I think the only comparison that makes sense is the benefit from the scan.
So if you are certain that the benefit of the scan is, no matter what the particular case, going to be worth much more than a 1/1000 chance of getting cancer, then that is a reason to ignore the risk.
Taking your numbers at face value, it seems the problem you're having is the epidemiological interpretation of risk as it pertains to patient populations. You can decide for yourself if a 1/2600 risk is acceptable to you, but doctors are in a position to decide for a far larger number of people.
If 10m people are exposed per year to the given risk you outline, the expected number of additional cancers is ~4k people over 20y. In 10 years of scanning, that's 40k additional cancers over the next 30 years. For elderly people over 70, this may be less of an issue, but for everyone else, this is definitely a problem!
Epidemiological studies likely overstate the risk. If you read the Australian study for example, they certainly could not determine with certainty how many CT scans an individual had, because they did not include CT scans performed in hospitals. I would say that MOST CT scans performed in children would happen in hospitals. Therefore, a person having one CT may simply be a marker of them having many more CTs which are not captured by the study.
There were also other unusual correlations in the data. For example, CT scans of the brain seemed to increase the risk of cancer elsewhere in the body, and scans of the abdomen increased the risk of brain cancer. This seems implausible, and implies to me that at least some of the correlation between CTs and cancer is likely to be explained by some third factor whereby people with an increased risk for cancer have more CT scans. The most telling correlations are probably for rare tumours, like soft tissue cancers eg sarcoma, which show an increased risk post CT. These cancers are rare and have few known risk factors, so this correlation is more believable. But these events were much rarer than all cancers in the cohort.
But doesn't this effectively reduce to "we don't know?"
FWIW I have had one CT scan in my life (in childhood I had a seizure which was probably caused by medicines I was taking) and they did one to rule out brain tumors. Probably a reasonable choice given that all the other tests for other stuff kept coming back negative. But I wouldn't suggest doing one without either a clear immediate need or else a significant concern and no materialized alternative causes for a symptom.
The article is terrible and you've done a good job of explaining why. But there are two ways to look at this:
1. From an individual's perspective
2. From society's perspective
Let's make up some numbers for illustration. If getting a CT scan gives someone 0.01% chance of getting cancer, the risk to any individual is negligible. But to society, that means 100 extra cases of cancer.
But doctors have that pesky "do no harm" credo that makes them consider whether the benefit of CT scans is worth the harm of 100 people getting cancer that wouldn't have otherwise gotten it.
It is proper for society to examine this without dismissing 100 people getting cancer as "negligible".
Interestingly Stewart Brand was out this year arguing http://edge.org/response-detail/25392 against of the the Linear No-Threshold model of radiation risk:
"The "Linear" part of the LNT is true and well documented. Based on long-term studies of survivors of the atomic bombs in Japan and of nuclear industry workers, the incidence of eventual cancer increases with increasing exposure to radiation at levels above 100 millisieverts/year. The effect is linear. Below 100 millisieverts/year, however, no increased cancer incidence has been detected, either because it doesn't exist or because the numbers are so low that any signal gets lost in the epidemiological noise."
IDK if his case if convincing or not. In any case, even if say 10, 50 or 100 millisieverts a year is something the human body can shrug off with no increase in risk, I imagine that might not apply to 10-30 millisieverts delivered in a very short interval of time.
The article's first sentence annoys me right off the bat:
"Despite great strides in prevention and treatment, cancer rates remain stubbornly high and may soon surpass heart disease as the leading cause of death in the United States."
This seems to be implying that cancer death rates are growing and will soon "surpass" those of heart disease. While the article is technically correct, this is due to the fact that deaths per year from heart disease have been going down in the US since 1975 (see here: http://www.heart.org/idc/groups/heart-public/@wcm/@sop/@smd/...)
It's irritating because the article's premise is flawed. It also gives no statistical data to back the claim that cancer rates are increasing.
It also seems to imply that medical tests which expose us to radiation are the cause of supposedly increasing cancer rates... which _seems_ a bit alarmist?
That would actually be a sound argument: If we assume a linear damage model for radiation exposure (which is a generally accepted model for these circumstances), then there is no safe dose. Instead, any exposure increases your lifetime risk of cancer. It is therefore not useful to talk about how medical imaging causes an individual case of cancer.
But for a larger population we can figure out what the cancer risk without medical radiation exposure would be, and what the observed probability is. We can then ascribe the difference to these medical tests. Obviously there are a number of ways to fuck up this analysis. Geological differences in the natural radiation dose shouldn't be underestimated. However, almost half of the lifetime radiation dose of a human does come from medical applications, and it would certainly be good to reduce that.
Really... fixating on the risk of cancer at all is a mistake. As other commenters have said, it's about balancing the risk with the value. Instead, we should find
a) How much radiation one might on average incur due to medical reasons
b) How many years of life that causes us to lose on average (or per capita)
c) How many years of life the average person gains due to the use of this technology.
As long as c - b > 0 (in a real way) we don't really have a problem here. We have an optimization to make. I don't see any evidence here that c - b <= 0. I also don't see any evidence that c - b > 0. Any other point seems moot.
Indeed. I would also like to see that British study that claims a link between CTs and leukemia – I smell selection bias. It is however true that a CT does imply a significant radiation dose.
This article is especially frustrating in that the authors seem to be doctors in the appropriate fields. I assume they just went too far in dumbing down the matter, which together with their source-less references to a dazzling amount of numbers and studies ends up obscuring their main point: A culture of using the “best” medical tool available instead of the “appropriate” tool can have adverse health effects, and has to stop.
All in all, there is a reason this article was filed under Opinions, not Science.
Because it wants to scare you, not reassure you. If it had started, "We've been so successful in tracking down and treating the things that lead to heart disease, it may soon drop to second place leaving Cancer as the #1 cause of death." Then you would be all happy that you weren't going to die of a heart attack and realize that your risk of dying from cancer hadn't changed (actually its been going down as the cohort of major smokers leave the population). But who wants to feel good about this stuff really? :-)
There's plenty of cognitive dissonance now that the stuff that kills us anymore is the stuff we understand the least. Actuarial tables aren't something we can reason about intuitively.
I was shocked to learn that an nMRI (where the nuclear "n" is usually silent) doesn't involve radioactivity. Such careful PR to avoid confusion about electromagnetic radiation, and it didn't even work?
This is an important point to make. In fact US deaths from cancer are on the decline too:
> An American Cancer Society report finds steady declines in cancer death rates for the past two decades add up to a 20 percent drop in the overall risk of dying from cancer over that time period.
Of course I'd rather get a CT scan sooner than an MRI later if I'm a serious trauma patient. But CT scans are way over-used for procedures that are not time-critical.
Agree, and it's not opinion, it's scare-mongering linkbait. Ridiculous to see that along with no actionable data from NYT. I'm giving myself a stroke just thinking about it.
Big elephant in the room: Pre-test ban atmospheric nuclear tests.
Of course, there's nothing anyone can do about it. The somatic damage period is probably more or less over, but we are transitioning through the genetic damage period.
If this was a big elephant in the room, then I would expect there to be some modicum of evidence that this causes any increase in cancer risk. Maybe a shred of evidence that cancer rates have gone up? Anything. We'll wait.
Isotopes of specific atoms have a different biochemical targetting and effect than EM radiation. Iodine is concentrated in the thyroid, strontium makes its way to the bone (close to hematopoetic stem cells), etc.
I took more than 20 in a couple of months (ordered by myself) after doctors couldn't find anything concrete (later on the current diagnostic is "fybromialgia" and the symptoms remain nearly 2 years later). I was aware of cancer danger but I needed to find some treatment before ending completely mad.
You may be interested in http://www.intidyn.com/Newsroom/article-0009.html - the probable cause of fibro has been identified - which will be a huge boon to the sufferers - including my girlfriend.
Than you. I'm very up to the news on r/fibro (reddit) and I already read that article but I'm glad you brought it up here. Since my diagnostic I'm also trying to make my way to develop health tech that could help mitigate (completely or partially) the pain and the other symptoms, so now I'm living in the bay area instead of my own country.
Specifically, the American Dental Association's
guidelines for heathy persons suggest that
* children receive 1 x-ray every 1-2 years,
* teens every 1.5-3 years,
* and adults every 2-3 years.
Typical dental x-ray's expose you to drastically less radiation than a CT. Wikipedia:
> The dosage of X-ray radiation received by a dental patient is typically small (around 0.150 mSv for a full mouth series, according to the American Dental Association website), equivalent to a few days' worth of background environmental radiation exposure, or similar to the dose received during a cross-country airplane flight (concentrated into one short burst aimed at a small area)
Before getting alarmed consider doing the math to assign numerical value to level of danger. Wikipedia article on Sievert has the formulas for it, as well as benchmark values to judge the outcome.
The standard defense of the safety of x-ray machines seems to be that you get more radiation from long haul flights. Well, there's a strong argument that flying isn't safe either. Pilots and stewards apparently have elevated cancer rates.
The amount of radiation you receive in one dental x-ray is approximately 1/8th the amount you receive in a single cross-country plane flight.
I mean, you still don't want to overdo it. All things being equal, you want to limit your exposure to ionizing radiation across the board. But dental x-rays generally aren't a public health menace, and they're seldom overprescribed to a dangerous degree. I'd much rather get a dental x-ray that prevents costly and dangerous dental disease in the proximate future, given the fairly low dosage involved.
For back pain? More than half of the people at some point in life develop some for back pain. It's scary so if you can afford a scan you get it. Of course there's nothing wrong and the pain goes away by itself in following months, usually after switching chair in which you spend most of your waking hours.
I am a surviving AML patient, relapsed once and had a stim cell donor. I have had over 50-60 CT scans and I have one or two a month to monitor my lungs for fluids. This article makes me chuckle cause who knows what it's doing to me, but without the CT scans to spot pneumonia and other infections in my lungs I would probably have died already.
I have a few oncologist friends. I think that their point of view is that once you go to see them, getting a CT or 50 is the least of your problems. So, if they even think there is something wrong, you're getting a CT. The risk of having a problem now is much worse than the remote risk of something else going wrong in the future. If you survive this bout, who cares about the extra radiation exposure.
Being able to worry about that later is a good problem to have.
That's exactly how I feel. CT sure sign me up. Ive had so much chemo therapy and radiation xrays and scans that I am sure my lifespan is shortened a lot. However I am alive 6 more years than I should have been, and I have a son and a wife that I would have never experienced.
I know several people that died of cancer, and as far as I know none of them had a CT scan before it. In contrast, the one who was often scanned during his illness, lived almost 10 years with cancer.
The article just says CT scan has higher radiation but other than that no hard facts are presented. Looks like the NYT is writing research articles now...
Let's simplify this. Industrial waste is everywhere. Old buildings are built with cancerous materials and we are expose to all kinds of radiations and air pollutions. We eat junk food, we don't exercise much. Kids are playing with toys painted with lethal chemical substances. Second-hand smoking is always present. We eat overfried food and we also sleep late.
So the story is clear and doesn't require some heavy scientific investigation. We are risking.
Why doesn't anyone mention that our diets are also culprits because they weaken our immune systems. Diets full of fats cholesterol and cooked vegetables do not have the required nutrients that we need day to day. This is pretty eye opening: http://www.imdb.com/title/tt1528734/?ref_=nv_sr_1
since the media is now exposing this secret there must have already been a decline in CT scans, otherwise the media would never say a word about it. The media never exposes a mainstream money making scam until the money has gone out of it.
166 comments
[ 2.6 ms ] story [ 217 ms ] threadHowever, every decision in medicine is (or should be) a risk-vs-benefit analysis. Cancer is not the only thing you can die from. If you suffer a head injury and end up in the ER and get a CT scan, you may increase your long-term risk of cancer, but you are also drastically reducing the risk of dying from a brain hemorrhage that couldn't be identified by any other method.
But the article was talking about the increase in CT usage over the past 20 years. That's largely been driven (in the US) by misaligned incentives that reimburse procedures at much higher rates that clinical decision making. Put simply, the person who owns the CT machine makes much more than the doctor who interprets the results. And so we have had a blossoming of imaging centers, and CT machines have moved into outpatient cardiology and even family care practices.
One of the major goals of Obamacare is addressing these misaligned incentives and shifting to a model where providers are paid to keep people healthy (outcome driven) rather than on volume (fee for service).
Another issue has been the difficulty of sharing/accessing existing imaging data, so tests are just repeated to save time (rather that save cost or adequately balance safety). Our long, painful journey to electronic record standardization should also help with that.
Everyone likes to shit on lawyers, but US doctors routinely take on, and fail to disclose, conflicts of interest that would get a lawyer disbarred in a heartbeat.
For example - someone comes into the ER with simply a headache. On its own this should not warrant a CT scan. But if a doctor does not order one, and that patient leaves and eventually comes back with a brain tumor (extremely small odds, but not zero), then the following malpractice suit would almost certainly result in a plaintiff victory and the end of a doctor's career.
Malpractice is a real thing and real victims deserve their due. But lawyer attack ads and no limits on "pain and suffering" payouts (often multi-millions) I believe are a critical part of the difficult healthcare situation in America that continues to go unaddressed.
That does not look right to me. A single CT scan is 2-7 millisieverts, and exposures under 13 can not be linked to health effects - look for UNSCEAR in http://en.m.wikipedia.org/wiki/Sievert
If you do the math by ICRP formulae, you end up with increase chance of cancer of 1 in 2600 over the next 20 years from a single 7ms CT scan today. This compares favorably with "natural" risk that is 1 in 10 without any extra exposure above background radiation.
Now if you do a scan every year for the next 20 years your chances go up to 1 in 130. So there is something to worry about, but article overstates the cause.
Unless the article is wrong about the number of CT scans many people are getting, that's going to result is a huge number of avoidable cancer cases.
From 'Physics for Future Presidents', they say it is commonly accepted that we have a 20% chance of DYING from cancer before calculating for outside influences. http://books.google.com.au/books?id=6DBnS2g-KrQC&pg=PA98&lpg...
Let's say the average person does not get a CT scan every year for 20 years, but rather gets 5 scans over their lifetime. Those scans may detect an early stage of cancer, therefore saving the persons life.
They're risk of dying from cancer is approximately 20.2%. I suggest with the CT scan, their still coming out on top.
Incidentally, this is exactly why I included the numbers - so you can check them, and why I don't like the headline article - no numbers and no references, so there is nothing to check, only vaguely scary claims.
It's been huge in dental x-rays, going from film to CR/DR (although dental isn't huge, it's routine, and involves a large patient population including kids.)
We probably will be <5 mSv for whole-body pretty soon. Ultimately there's no reason it can't be well under 1 mSv.
Fluoroscopy on the other hand is easily 50 mSv/min and multi-hour procedures (!!!). People get acute effects from that.
http://www.usnews.com/science/articles/2012/01/17/phsycists-...
A full-body CT scan results in 12 mSv; a mammogram 0.13 mSv—a hundred times less. The risks from these procedures, according to AAPM, are too low to have been determined reliably, and may be "nonexistent."
Looks like this debate has been going on for a while now.
[1] http://www.bmj.com/content/346/bmj.f2360
But that is a meaningless comparison. The doctor should be comparing this additional risk, to the benefit of the scan.
The "natural" risk of developing cancer is totally irrelevant to the cost-benefit analysis.
If I want to know whether to do a CT scan, the only relevant fact is the increase in probability (in an absolute sense) of cancer that it causes.
It seems like either you, or the entire field of medicine, is obfuscating this basic fact using some field-specific concepts.
EDIT: It seems like you are referring to relative risk (http://en.wikipedia.org/wiki/Relative_risk). But as I said, there is no reason that relative risk should be considered in this case.
I wonder though if there should be a cutoff somewhere, below which you stop caring? I used background cancer rates as an anchor to judge if the cutoff has been reached, without getting specific about benefits of treatment in each particular case. Would you suggest another cutoff level that is broadly applicable?
So if you are certain that the benefit of the scan is, no matter what the particular case, going to be worth much more than a 1/1000 chance of getting cancer, then that is a reason to ignore the risk.
If 10m people are exposed per year to the given risk you outline, the expected number of additional cancers is ~4k people over 20y. In 10 years of scanning, that's 40k additional cancers over the next 30 years. For elderly people over 70, this may be less of an issue, but for everyone else, this is definitely a problem!
There were also other unusual correlations in the data. For example, CT scans of the brain seemed to increase the risk of cancer elsewhere in the body, and scans of the abdomen increased the risk of brain cancer. This seems implausible, and implies to me that at least some of the correlation between CTs and cancer is likely to be explained by some third factor whereby people with an increased risk for cancer have more CT scans. The most telling correlations are probably for rare tumours, like soft tissue cancers eg sarcoma, which show an increased risk post CT. These cancers are rare and have few known risk factors, so this correlation is more believable. But these events were much rarer than all cancers in the cohort.
FWIW I have had one CT scan in my life (in childhood I had a seizure which was probably caused by medicines I was taking) and they did one to rule out brain tumors. Probably a reasonable choice given that all the other tests for other stuff kept coming back negative. But I wouldn't suggest doing one without either a clear immediate need or else a significant concern and no materialized alternative causes for a symptom.
1. From an individual's perspective
2. From society's perspective
Let's make up some numbers for illustration. If getting a CT scan gives someone 0.01% chance of getting cancer, the risk to any individual is negligible. But to society, that means 100 extra cases of cancer.
But doctors have that pesky "do no harm" credo that makes them consider whether the benefit of CT scans is worth the harm of 100 people getting cancer that wouldn't have otherwise gotten it.
It is proper for society to examine this without dismissing 100 people getting cancer as "negligible".
"The "Linear" part of the LNT is true and well documented. Based on long-term studies of survivors of the atomic bombs in Japan and of nuclear industry workers, the incidence of eventual cancer increases with increasing exposure to radiation at levels above 100 millisieverts/year. The effect is linear. Below 100 millisieverts/year, however, no increased cancer incidence has been detected, either because it doesn't exist or because the numbers are so low that any signal gets lost in the epidemiological noise."
IDK if his case if convincing or not. In any case, even if say 10, 50 or 100 millisieverts a year is something the human body can shrug off with no increase in risk, I imagine that might not apply to 10-30 millisieverts delivered in a very short interval of time.
http://www.propublica.org/article/drive-by-scanning-official...
http://www.xinexus.ch/nuclear-radiation-dosimeter/index.html
edit: I think I got the wrong thing there.. better go for this:
http://www.hotray-info.de/html/radioactivity.html
"Despite great strides in prevention and treatment, cancer rates remain stubbornly high and may soon surpass heart disease as the leading cause of death in the United States."
This seems to be implying that cancer death rates are growing and will soon "surpass" those of heart disease. While the article is technically correct, this is due to the fact that deaths per year from heart disease have been going down in the US since 1975 (see here: http://www.heart.org/idc/groups/heart-public/@wcm/@sop/@smd/...)
It's irritating because the article's premise is flawed. It also gives no statistical data to back the claim that cancer rates are increasing.
But for a larger population we can figure out what the cancer risk without medical radiation exposure would be, and what the observed probability is. We can then ascribe the difference to these medical tests. Obviously there are a number of ways to fuck up this analysis. Geological differences in the natural radiation dose shouldn't be underestimated. However, almost half of the lifetime radiation dose of a human does come from medical applications, and it would certainly be good to reduce that.
a) How much radiation one might on average incur due to medical reasons b) How many years of life that causes us to lose on average (or per capita) c) How many years of life the average person gains due to the use of this technology.
As long as c - b > 0 (in a real way) we don't really have a problem here. We have an optimization to make. I don't see any evidence here that c - b <= 0. I also don't see any evidence that c - b > 0. Any other point seems moot.
This article is especially frustrating in that the authors seem to be doctors in the appropriate fields. I assume they just went too far in dumbing down the matter, which together with their source-less references to a dazzling amount of numbers and studies ends up obscuring their main point: A culture of using the “best” medical tool available instead of the “appropriate” tool can have adverse health effects, and has to stop.
All in all, there is a reason this article was filed under Opinions, not Science.
http://www.cancer.gov/newscenter/newsfromnci/2012/CTpediatri...
http://www.thelancet.com/journals/lancet/article/PIIS0140-67...
Note the large difference in presentation. NCI:
"...a small increased risk of leukemia and brain tumors..."
"...The researchers emphasize... the benefits of clinically appropriate CT scans should outweigh future cancer risks"
NY Times:
"...three times more likely to develop leukemia and brain cancer"
"...distressingly little evidence of better health outcomes"
It's some sort of golden rule of sensationalism: if the risk is minuscule, report it as a large multiplier over a tiny baseline.
(Or possibly, an absolute incidence count out of a gigantically large population. NYT, thoughtfully, did both).
I was shocked to learn that an nMRI (where the nuclear "n" is usually silent) doesn't involve radioactivity. Such careful PR to avoid confusion about electromagnetic radiation, and it didn't even work?
> An American Cancer Society report finds steady declines in cancer death rates for the past two decades add up to a 20 percent drop in the overall risk of dying from cancer over that time period.
http://www.sciencedaily.com/releases/2014/01/140107102634.ht...
is what the title should have said. This article is the worst form of opinion.
Of course, there's nothing anyone can do about it. The somatic damage period is probably more or less over, but we are transitioning through the genetic damage period.
https://en.wikipedia.org/wiki/Background_radiation
Natural background: 2.40 mSv/year (world average)
Atmospheric testing: "peak of 0.11 mSv in 1963"
http://seer.cancer.gov/statfacts/html/prost.html
http://seer.cancer.gov/statfacts/html/colorect.html
http://seer.cancer.gov/statfacts/html/breast.html
http://seer.cancer.gov/statfacts/html/lungb.html
I find this rather disturbing.
I was personally very surprised and alarmed by this.
> The dosage of X-ray radiation received by a dental patient is typically small (around 0.150 mSv for a full mouth series, according to the American Dental Association website), equivalent to a few days' worth of background environmental radiation exposure, or similar to the dose received during a cross-country airplane flight (concentrated into one short burst aimed at a small area)
If you don't want to do the math, consider this handy chart: http://xkcd.com/radiation/
I mean, you still don't want to overdo it. All things being equal, you want to limit your exposure to ionizing radiation across the board. But dental x-rays generally aren't a public health menace, and they're seldom overprescribed to a dangerous degree. I'd much rather get a dental x-ray that prevents costly and dangerous dental disease in the proximate future, given the fairly low dosage involved.
For what?
The advice for most people would tend to be "lose weight, get exercise, check your beds and chairs; and carefully take paracetamol for the pain".
I have a few oncologist friends. I think that their point of view is that once you go to see them, getting a CT or 50 is the least of your problems. So, if they even think there is something wrong, you're getting a CT. The risk of having a problem now is much worse than the remote risk of something else going wrong in the future. If you survive this bout, who cares about the extra radiation exposure.
Being able to worry about that later is a good problem to have.
For the discussion at hand, http://en.wikipedia.org/wiki/Magnetic_resonance_imaging#MRI_... has some discussion.
The article just says CT scan has higher radiation but other than that no hard facts are presented. Looks like the NYT is writing research articles now...
So the story is clear and doesn't require some heavy scientific investigation. We are risking.
http://www.huffingtonpost.com/2013/08/27/stress-cancer-gene-...
If you think cancer is all about radiation, you are wrong..
It's the first thing I check with before looking for any details (which are conveniently linked at the bottom, by the way).