Impossible to draw any conclusions from such a convoluted and problematic model. No mention of how they determined patients were unique, or whether multiple scans were counted for a single patient. No mention of patient data - seems that covariates were estimated, leading to greater uncertainty. For example, we have no idea if any of these patients already had cancer before getting a scan. And of course, this entire model is incapable of answering the question that patients actually care about: not "will I get cancer from this?" but "will this scan more likely increase or decrease my lifespan and/or quality of life?".
ashleyn 23 hours ago [-]
Seems pretty common sense to me that you're gonna have more people with hidden cancers coming in to get CT for phantom pains, etc and later discover they had cancer all along. That doesn't mean CT caused it. Did the study control for this?
hn_throwaway_99 8 hours ago [-]
> Did the study control for this?
No, because that's not how the study worked, i.e. it wasn't actually tallying cancer rates from people who had CTs. It basically just looked at the amount of radiation that a CT scan gives a person, and then extrapolated the cancer that would be expected from that radiation dose based on other data we have of e.g. people exposed to radiation in their jobs, and nuclear fallout occurrences.
tedivm 23 hours ago [-]
Previous studies I've read did account for this, and put the number at about 3%. That said CT manufacturers have been working on a bunch of technology to make this better, either by doing a better job at not aiming at sensitive areas or by reducing the amount of radiation needed to get the same resolution in the images.
mirekrusin 23 hours ago [-]
The whole dataset seems like something hard to work with, population that needs CT scan in the first place is very biased, people don't do CT scans for fun but because there is something weird that docs can't explain already.
hughw 23 hours ago [-]
It's unclear to me whether you read the journal article or just the Ars article? If you're referring to the journal article that gives your assessment much more weight.
delichon 23 hours ago [-]
I went to the doctor complaining of constipation. He sent me for a CT scan which showed that I was literally full of shit. The prescription was for a large dose of MiraLax. Now I wonder if the risk of the CT scan was really justified given that plenty of people already tell me that for free and without radiation.
ramraj07 23 hours ago [-]
A. Newer CT scan machines use lower radiation doses.
B. If you're getting only one scan a year you're fine and within yearly limits of radiation dosage considered acceptable.
Remember that you'll get comparable levels of radiation even if you commute through the grand central station every day.
This paper is for lack of a better word, crap. It's becoming sensational for the conclusion it makes and I'm afraid it's now going to create more harm because of that.
behnamoh 23 hours ago [-]
> B. If you're getting only one scan a year you're fine and within yearly limits of radiation dosage considered acceptable.
But doesn't it make a difference if that "acceptable yearly limit" is spread out throughout the year as opposed to a few minutes of CT scan session?
dmd 12 hours ago [-]
Yes, the term is DDREF - Dose and Dose Rate Effectiveness Factor.
odyssey7 23 hours ago [-]
I really don’t buy it if someone says the opposite.
DiggyJohnson 21 hours ago [-]
Tf is going on in Grand Central?
itishappy 21 hours ago [-]
Granite.
dwroberts 20 hours ago [-]
I had a CT of my pelvis and abdomen recently and worked out it was equivalent to about 5 years worth of background radiation.
The dose required is actually quite a lot higher than typical comparisons to eg chest X-rays and the like
declan_roberts 23 hours ago [-]
What about contrast? I've heard it's really hard on your thyroid.
uh_uh 22 hours ago [-]
> Remember that you'll get comparable levels of radiation even if you commute through the grand central station every day.
Gemini says this:
> A single typical CT scan delivers a dose that is roughly 1,000 to over 5,000 times higher than the dose you'd get from spending a few hours in Grand Central Terminal.
Where did you get that from?
dragonwriter 22 hours ago [-]
If the hallucination machine can cite a source, check and cite that for facts, but don't cite the hallucination machine.
uh_uh 22 hours ago [-]
Weird you don't have this requirement for the OP spewing his urban myths above.
ssl-3 21 hours ago [-]
Human hallucinations are natural.
Machine hallucinations are avoidable.
uh_uh 19 hours ago [-]
Was it hallucinating here, or are the commenters hallucinating? What OP is saying is just not true. A CT scan and normal daily commute in Grand Central station are NOT comparable in terms of radiation received. Somehow this is controversial because an AI said it?
ssl-3 9 hours ago [-]
The machine appears to have hallucinated the incomparable comparison, instead of a human.
(And I'm not picking on the machine at all here. I use it all the time. At first, I used to treat it like an idiot intern that shouldn't have been hired at all: Creative and full of spirit, but untrustworthy and all ideas need to be filtered. But lately, it's more like an decent apprentice who has a hangover and isn't thinking straight today. The machine has been getting better as time presses on, but it still goes rather aloof from time to time.)
Guvante 22 hours ago [-]
Did you actually discredit someone or have you not properly considered your units in this response?
Commute through the Grand Central station everyday is certainly not a few hours.
And people don't tend to get a CT scan very frequently so the timeline here is massive.
uh_uh 22 hours ago [-]
In your opinion how many hours spent in Grand Central station equal the radiation received from a CT scan?
This data is from 2006. Over 20 years, there has been substantial progress in CT radiation reduction through model-based iterative reconstruction and now ML-assisted reconstruction, aside from iterative advances in detector sensitivity and now photon-counting CT.
In clinical practice, those doses are about 2-3x what I see on the machine dose reports every day at my place of work.
In thin patients who can hold still, I've done full-cycle cardiac CT and achieved a < 1 mSv dose. We are always trying to get the dose down while still being diagnostic.
Source: Practicing radiologist.
itishappy 15 hours ago [-]
Fair enough. That was the first number I pulled from Google, but I trust your source a good deal more.
ramraj07 15 hours ago [-]
I used the word comparable. Given they are in the same ballpark of log scale i stand vindicated in my opinion.
Also there's an apple store there. RIP all the geniuses there i suppose
ramraj07 15 hours ago [-]
So if you pass through GCT every day it does become comparable to a CT scan?
AaronAPU 21 hours ago [-]
I had a CT scan ordered for abdominal discomfort which had been making sleep a nightmare for years.
I started taking ag1 and Metamucil and the stomach discomfort has completely gone away over a span of weeks/months.
The resulting dramatic improvement in sleep cascades to just about everything in my life and different recurring health problems keep disappearing now.
It’s crazy how many problems can be caused by apparently just not getting enough fiber.
Never ended up getting the CT scan, which probably would’ve been expensive and involve some small degree of risk.
ceejayoz 23 hours ago [-]
Yeah, a plain old abdominal x-ray might've sufficed to diagnose that.
Or the pre-x-ray technique of abdominal palpation.
delichon 23 hours ago [-]
The same scan found a large goiter which led to surgical removal of a malignant thyroid tumor. So I have mixed feelings.
pama 22 hours ago [-]
If its any consolation, having diagnosed a malignant papilary or follicular thyroid tumor (surprizingly) is correlated with equal or slightly increased lifespan compared to the population that did not have this tumor—maybe it is because of having more frequent or better access to healthcare, which is harder to control in such epidemiological studies. It is one of the few positive known relationships with cancer.
delichon 22 hours ago [-]
Only after the procedure my ENT told me that if she were to pick a cancer to get it would be this one, and that the experts are trying to rename it from cancer to neoplasm because of its relative benignity. But I hadn't heard that it could actually be a positive. That underlines the mixed blessing of screening tests.
liamwire 6 hours ago [-]
It also underlines the second-order risks of unneeded diagnostic screenings, even those that don’t include ionising radiation and its ilk, as the surgery you may otherwise have not had is itself not free from risk. Of course the case generalises out from there as well to not only this specific cancer.
MaKey 22 hours ago [-]
Sounds like the CT scan was a clear win then.
ceejayoz 23 hours ago [-]
An abdominal CT found a goiter?
delichon 23 hours ago [-]
They did chest too because I also had some higher up pain on my side. That also resolved with the bowel flush.
trillic 23 hours ago [-]
Same. The CT is to rule out diverticulitis and in my case, since the pain was located in my lower right abdomen, appendicitis.
I was just full of shit, as usual. Now I eat salads and drink more water when I am at elevation.
david38 22 hours ago [-]
Why would you go to the doctor for that instead of first trying one of the many known solutions?
* a tablespoon of epsom salt
* a tablespoon of mineral oil
* several OTC products
delichon 22 hours ago [-]
I did try a boatload of OTC products, and eventually went to a generalist and then a specialist when it became severe and chronic. The OTC products recommend that on their labels. I now manage it with careful diet and a daily dose of polyethylene glycol.
kristjansson 23 hours ago [-]
Scott Alexander’s article on altruistic kidney donation weighed the initial CT scan as a heavy negative, like an incremental 1 in 650 risk of death. Shocking to me at the time, but the number seemed to check out, at least as a first order estimate.
jhallenworld 23 hours ago [-]
Yuck, I have recurrent kidney stones and have had many CT-scans. It seems to have become the standard procedure when you complain of abdominal pain at the ER. Years ago I remember just getting an X-ray.
What's interesting is I needed surgery to remove the most recent stones, and I've not had a CT-scan since- the urologist uses ultrasound.
On the other hand, I've had fluoroscopy.. probably worse than even CT-scans.
daedrdev 23 hours ago [-]
Things like this are why we don't run general screening for rare diseases.
The risk from screening, and the risks from further diagnosis and accidental treating of false positives can be much higher than the disease itself as long as it is rare enough.
eqvinox 22 hours ago [-]
I think your logic arrow is the wrong way around. We only run screening for rare diseases when indicated, and then get things like this.
If CT scans are performed on more than 5% * (1 + false positive rate) of suspected cancer cases, having a CT scan in the history of 5% of cancer cases is entirely expected.
oceanplexian 22 hours ago [-]
This is what the healthcare community claims, but they're wrong.
I took a preventative MRI run by an ML/AI company that the healthcare folks say is a bad idea. I didn't discover any hidden cancers but they did find 1-2 emerging health issues that were preventable with simple diet and lifestyle changes.
If everyone showed up to their doctor asking for preventative imaging, it would overwhelm doctors since there aren't enough resources to treat everyone who is sick. Your individual health will always be less important than the integrity of the system.
daedrdev 18 hours ago [-]
No its literally just a statistics issue. Say you screen someone for a 1 in a million disease with a 0.001% false positive rate. If you find something and have to do a biopsy to figure out if its a real issue or not, you will have 99.9% of them be for nothing. Biopsies are actually risky procedures that can have dangerous complications that can and do harm people. Say your biopsy has a 99% accuracy. This means even after all that someone with a confirmed biopsy only has a 10% chance of having the disease, and may get dangerous and life changing treatment for nothing.
itishappy 20 hours ago [-]
> they did find 1-2 emerging health issues that were preventable with simple diet and lifestyle changes
Sounds like the exact same results you'd have gotten without imaging.
ceejayoz 22 hours ago [-]
"The for-profit company's bullshit generator promised it helped me with some minor stuff" is perhaps not as compelling evidence as you imagine it to be.
oceanplexian 22 hours ago [-]
At least one of the issues was a high definition image of a degenerating disc, a child could diagnose it by comparing it to the image of a healthy spine, never mind an algorithm.
You would have no idea you had it without imaging, since in the early stages you feel nothing.
Now I can work to build up muscle around that area and avoid over exerting that part of my back, instead of dealing with pain and being prescribed opiates in 20 years. Another example of how the system has killed countless people and absolutely failed the public.
systoll 13 hours ago [-]
> You would have no idea you had it without imaging, since in the early stages you feel nothing.
From 30 years of age, disc degeneration is more likely than not. You don’t need a scan to tell you you’re in the early stages of it.
Tepix 23 hours ago [-]
How many lives did those CT scans save vs. how many lives were lost due to the additional cancer cases they caused? That's the question, isn't it?
xeornet 23 hours ago [-]
Well actually let’s find out whether they do cause it or not. Patients ought to know the risks beforehand if so.
The calculation as to net benefit can be done later.
odyssey7 23 hours ago [-]
X-ray radiation causes cancer.
CT scanners don’t use magic non-carcinogenic x-rays.
Socrates is a man, men are mortal, Socrates is mortal.
We have the technology. We should have moved on to MRIs for nearly all scans years ago.
itishappy 20 hours ago [-]
They're not interchangeable. CT scans have better resolution, take significantly less time, and are generally sensitive to different things.
odyssey7 18 hours ago [-]
You’re absolutely right, they’re not interchangeable. MRIs are better suited for soft tissues.
If you’re looking for a broken bone, take a single x-ray image instead of a whole CT scan, which is a far higher dose of X-ray radiation.
itishappy 16 hours ago [-]
Largely agree, but still very much depends on what you're screening for. For example, my oncologist still recommends CT over MRI for post-surgical screening as the increased resolution makes it possible to detect tumors a bit earlier.
odyssey7 6 hours ago [-]
I’m not familiar with the parameters of the machines readily available to your provider, but I can say that the risk/reward scenario for an intervention for someone coming out of cancer surgery is distinct. We give cancer patients chemo and radiation that we would never give to someone who just showed up in the ER or was still undergoing preliminary diagnostics.
oyashirochama 21 hours ago [-]
I mean you can't when a non-insignificant amount of people have magnetic metal in their body.
liamwire 6 hours ago [-]
Please elaborate?
xeromal 23 hours ago [-]
People get weird when using math to calculate human lives.
nkrisc 23 hours ago [-]
As they should. It’s not difficult to use questionable math to justify very awful things.
lm28469 23 hours ago [-]
You can very easily come up with reasonable plans to euthanise sub categories of the population to "save" lives if you only care about the total numbers of people surviving...
sebastian_z 23 hours ago [-]
There can be big differences in radiation doses depending on the type of CT scanner used. Some radiology practices advertise low-dosage scanners [1]. So, if you need a CT scan you can ask for the dosage and find a practice that has a low-dosage scanner.
So 0.1% extra lifetime risk for every CT scan, I guess I went from 40% lifetime risk to 40.5, I guess I'll keep not drinking, not smoking and not being obese to help with the statistics.
odyssey7 22 hours ago [-]
Medicine: first, do no harm.
Why not use MRIs since they skip the problem entirely?
Don’t say cost or supply. That’s just because CT scans, misguidedly, have more demand. More demand for MRIs would unlock savings from scale.
enjoytheview 1 hours ago [-]
In my case, I had a lung issue and CT scans are more sensitive to air being where it shouldn't be. At least two of the 5 ct scans could probaly just have been x-rays tho.
qgin 11 hours ago [-]
You can do a brain CT to detect a stroke in about 5 minutes. An MRI takes 30-60 minutes. Both useful but in emergency medicine you need the speed.
odyssey7 7 hours ago [-]
Drive more demand for MRIs and they’ll get faster too
ChocolateGod 4 hours ago [-]
They'll always be slower than CT scans because physics.
itishappy 20 hours ago [-]
CT scans are better in a lot of ways. They're faster, higher resolution, and sensitive to different stuff than MRIs.
odyssey7 18 hours ago [-]
Radiographer: “MRI (magnetic resonance imaging) creates detailed images of the inside of the body using strong magnetic fields and radio waves, rather than X-rays. MRI is/was the holy grail for medical imaging professionals. Arguably the coolest images come from MRI”
Statistical topic are presented really poorly in the media.
If what the reader cares about is the risk to them, why is the proportion of all cancers caused by CT relevant? If we found a way to prevent 50% of all other cancers would CT become higher risk?
jchw 22 hours ago [-]
Stuff like this hits me in my health anxiety pretty bad, even if I know deep down that there's no point, on an individual scale, in worrying about this sort of thing; it's more of interest to clinicians for decision making. Still... I've had a couple CT scans with contrast in the past year, and that is probably somewhere around 20-25 mSv of radiation. In the grand scheme of things, it's really not that catastrophic of an amount, but it's a hell of a lot more than background radiation. Scary.
consp 22 hours ago [-]
> but it's a hell of a lot more than background radiation. Scary.
Not if you fly decent distances a dozen times a year or more.
jchw 22 hours ago [-]
Makes me wonder if 10 mSv all at once is worse than 10 mSv over the course of a year. It seems that airline crews are only expected to be exposed to a dose from between 2 to 9 mSv annually[1], which makes a abdominal CT scan with contrast seem especially bad.
Of course, rationally speaking, I think at the individual level it's hard to really gauge this any more than any other residual risk factor. You could get very unlucky with cell damage from anything, more radiation just gives you more tickets to the lottery. I'm sure other factors play a role on an individual level and the risk to each person is not static.
I didn't read the JAMA article, but shouldn't it be possible to test that hypothesis differently? E.g., people get CT scans for fractures in knee or wrist. Cancer in those places is very rare, so of CT scans cause cancer, shouldn't there be noticeable difference between scanned and unscanned people?
itishappy 20 hours ago [-]
It's quite hard to give bones and joints cancer. Cancer prefers dividing cells.
ahartmetz 19 hours ago [-]
Some blood cells are produced in bone marrow and it's not rare to get "bone cancer".
itishappy 19 hours ago [-]
Yup, but it's significantly less common than most other forms of cancer.
ceejayoz 23 hours ago [-]
If cancer is also rare in those spots without a CT, that would seem to indicate a major confounding variable at play.
tgv 22 hours ago [-]
That's my point: if CT scans cause cancer, cancer in the wrist or knee should be much more frequent among people who had a wrist or knee CT scan than among the general population. CT scans are relatively new, so there probably is a record in each patient's history.
ceejayoz 22 hours ago [-]
Again, not necessarily. Different things cause different cancers. You're unlikely to get melanoma from smoking; you're unlikely to get liver cancer from a sunburn.
CTs may not cause significant amounts of wrist/knee cancer - I can't speak either way on that - but that wouldn't mean they're 100% safe elsewhere. For starters, wrist/knee imaging needs less radiation - they're relatively thin parts of the body, and relatively small regions.
tgv 3 hours ago [-]
But then the assumptions behind the article is not general, and the conclusions would have to amended to the radiation dosis and/or tissue. Which makes sense, of course.
sakex 23 hours ago [-]
What about MRI? Just had one. Sorry if it's a stupid question, I don't know much about this
hylaride 23 hours ago [-]
MRI's themselves produce no cancer risk as they're not ionizing radiation. There's SOME questions about SOME of the dyes used for SOME MRI procedures, but those are usually used in situations where the alternative is worse - so do it.
ashleyn 23 hours ago [-]
MRI doesn't use ionising radiation so it's a stretch. Most likely cause would have to be some toxic effect of the contrast dye (as opposed to any sort of ionising radiation), but no compelling evidence exists for that.
tgv 23 hours ago [-]
MRI's magnetic field is not strong enough. CT scans use Röntgen radiation, and that's known to cause ionization (the waves can displace electrons), which --in DNA-- potentially causes cancer.
bluGill 23 hours ago [-]
Depends. MRI itself is safe, but they often add "contrast" which is known to cause cancer (I'm not clear on if there is more than one choice for contrast though, or if they all cause cancer). Of course contrast is mostly used when they looking at a something - likely a tumor that might or might not be cancer to decide how to treat it - in that case does it matter that your long term cancer prospects go up when without it your short term prospects are not good.
rasmus1610 23 hours ago [-]
There is no compelling evidence that MRI contrast agent causes cancer. Gadolinium (the stuff that’s in the contrast agent) can deposit in the body, e.g. in the brain, but if this even has any consequences is still unclear. Nonetheless there is some nice research going on how to drastically reduce the amount of contrast agent needs to be administered through image postprocessing.
bluGill 21 hours ago [-]
Hmm. When I check a few years ago what looked like authortive people said it was - I will admit to not being an expert though.
mthomasmw 23 hours ago [-]
citation?
petters 23 hours ago [-]
You're safe
Zezima 24 hours ago [-]
by the time you are scheduled to get a CT scan, the possible diagnosis which lead to the CT scan is almost certainly riskier than the cancer.
Move along...
ceejayoz 23 hours ago [-]
No, not necessarily.
CT scans are likely overused; my spouse has several chronic conditions and after receiving dozens a year for a while, we started asking if a CT was clinically indicated, or just precautionary. Mostly the response is "just in case". I wish EMRs did a better job of highlighting how many CTs someone's had recently for this sort of decision making.
There've also long been problems with kids getting unnecessarily high adult doses of radiation. My dad's a peds radiologist and was heavily involved in the founding of https://www.imagegently.org/.
blitzar 23 hours ago [-]
The folks round these parts that transfuse the blood of young healthy people to boost their lifespan are probably having a regular CT scan too.
sph 23 hours ago [-]
I don’t think they roam among us “plebs”
blitzar 21 hours ago [-]
With the advent of these modern medical breakthroughs I believe we have been rebranded from "plebs" to "blood bags".
el_benhameen 23 hours ago [-]
My kid needed an abdominal ultrasound in the ER, but the ultrasonographer had gone home for the night. They did a CT instead, despite my concerns. CT missed the problem, which festered for several more years before being discovered during our next ER visit … on an ultrasound.
queuebert 23 hours ago [-]
The "almost certainly" that you brush off is the entire point of the calculation. Is it 95% certain or 99.5% certain? The exact balance between benefit and risk in medical procedures is exactly how it is determined when to use them in the standard of care.
stevenwoo 20 hours ago [-]
My first MRI about 30 years ago they did a precautionary CAT scan of my head because I had worked in machine shop (the place I worked had a machine shop and I used it for small personal projects), dunno if they do that anymore, but I was told ferrous bits in eyes had led to disastrous results for at least one patient.
AyyEye 23 hours ago [-]
I have a friend who went to an allergist last week for sinus issues. They did a CT scan within 5 minutes of coming into the office.
queuebert 23 hours ago [-]
If it's any consolation, a sinus CT is tuned to have a very low radiation dose compared to typical body CT scans.
chr1 23 hours ago [-]
In most cases instead of CT scan one could do the same diagnosis with MRI scan, which is only a bit more expensive.
ChocolateGod 23 hours ago [-]
The MRI scan takes 10x longer, uses helium (of which there isn't an infinite supply) and can't be used on people with certain implants.
miiiiiike 23 hours ago [-]
Yeah, no. A doctor that I had a feeling wasn't paying too close attention to what I was saying ordered a pelvic/abdominal CT with and without contrast, ~30-40 mSv. Nothing turned up on the scans. When I went back he said "nothing's wrong" and, confused, I described my symptoms again. He just said "Oh! You need physical therapy."
Two weeks of physical therapy and I was fine.
At the time I was mad about the money, now I'm just thinking "what a dumb way to (maybe) get gut cancer."
I was young. I thought I was scheduled for an MRI like the one I had for my sinuses. I didn't even know what a was CT at the time.
fatnoah 21 hours ago [-]
On the other side of the coin, my always healthy dad did 6 weeks of physical therapy for hip joint pain that turned out to be cancer, which was immediately detected when they finally decided to perform a CT scan. He passed away almost exactly 1 year later at 46 years old.
miiiiiike 10 hours ago [-]
I don't like this coin. Sorry about your dad.
cowfarts 24 hours ago [-]
[dead]
drpgq 8 hours ago [-]
Would you be able to see this effect comparing Americans and Canadians, assuming Canadians have way fewer CT scans on average?
tempera 5 hours ago [-]
Experts did not yet found that the mRNA Spike Vax causes cancer.
sagolikasoppor 5 hours ago [-]
I have had a lot of stomach issues, I have done 3 CT scans during my life and I am not even 40 years old. I worry already about the dosage I have gotten.
Though when I asked they said it was like a long flight trip to aroynd the globe. While I don't believe that, I do believe that they are much more effective than they were 10+ years ago. Also I wouldn't have got my stomach surgery without my first one.
justlikereddit 22 hours ago [-]
Radiation risk assessment have been modernized less than DARE propaganda.
The Linear No-Threshold LNT hypothesis/model is still the fundament of all radiation protection theory and the modeling used in it.
The problem with using that is that since twenty years back we've known that both antioxidant activity and DNA-repair and protection mechanisms do not scale linearly.
Meaning that a more correct approximation of reality would be using a Non-Linear With-Threshold model.
But because our culture of permanent radiation hysteria we're paralyzed when it comes to changing the overarching guidelines, even when everyday practice have practically left it behind.
Mistletoe 23 hours ago [-]
I’ve gotten heart scans twice to monitor coronary artery calcification and get an Agatson score. I wonder how risky this is? I feel like the last time I did it the technician said that the amount of energy they have to use now is much less due to advances in CT scanning machines.
I guess a heart scan is about like six months of natural background radiation according to this chart.
My father’s side has a history of heart attacks, so I’m trying to avoid that fate and consider the risks worth it.
hylaride 23 hours ago [-]
To maybe oversimplify it, cancer risk from radiation is all a stats game. The situations where you get a CT scan is either very rare (once or twice in a lifetime and often highly localized) or for a very acute issue (eg a heart attack or car accident) that is almost certainly worth the risks.
Also, ionizing radiation has a varying risks to different tissues. "Soft" tissues that have cells that divide a lot (lungs, colon, etc) are of greater risk than others. I wouldn't bat much of an eye for a CT scan on my knee, but would be more worried about a chest procedure. Again, more worried doesn't mean I wouldn't do it, as the alternative is either a much more expensive MRI, much more fuzzy echo-cardiogram, or wondering if my health is more seriously at risk.
The science is based on assumptions and extrapolation, they drew a linear plot line between rates of cancers at different levels of radiation, and then extended it down and to the left. But there is no actual experimental data showing a relationship between low dose radiation and cancer (Ironically there IS evidence that rates of overall cancers are lower in high altitude cities like Denver with more background radiation).
AStonesThrow 23 hours ago [-]
I’ve remodulated my phaser arrays and randomized the stochastic spectral frequencies ten times, but those Borg keep adapting!!1
canadiantim 23 hours ago [-]
It should be obvious that using the intense amount of ionizing radiation that CT scans use that of course they're causing a lot of cancer.
It's a shame our medical systems invested so heavily into CT machines at the expense of MRI's
justlikereddit 22 hours ago [-]
Theoretically causing a lot of cancers in modelling studies.
In practice a CT machine is also a much better workhorse for innumerable tasks that are very hard to effectively investigate with an MR machine, as MR imaging takes significantly more time, and requires more technical knowhow among the medical staff involved.
eqvinox 22 hours ago [-]
If this were true, we should be seeing a detectable, statistically significant higher rate of cancer in Japan, which has by far the highest rate of CT machines per person. (almost 3× that of the USA, which is still high even among high-income countries)
Considering the health and life expectancy in Japan, I call BS.
natmaka 8 hours ago [-]
Is the load factor of those Japanese machines similar to those used in the US?
Isn't life expectancy multifactorial?
eqvinox 5 hours ago [-]
The load factor would need to be lower than one third of the US to balance it out, which I'd claim is quite unlikely.
And yeah of course it's multifactorial. It'd make more sense to look at cancer data specifically, but I don't have that at hand. However, cancer is a leading factor in lifespan limits…
Rendered at 13:11:20 GMT+0000 (Coordinated Universal Time) with Vercel.
No, because that's not how the study worked, i.e. it wasn't actually tallying cancer rates from people who had CTs. It basically just looked at the amount of radiation that a CT scan gives a person, and then extrapolated the cancer that would be expected from that radiation dose based on other data we have of e.g. people exposed to radiation in their jobs, and nuclear fallout occurrences.
B. If you're getting only one scan a year you're fine and within yearly limits of radiation dosage considered acceptable.
Remember that you'll get comparable levels of radiation even if you commute through the grand central station every day.
This paper is for lack of a better word, crap. It's becoming sensational for the conclusion it makes and I'm afraid it's now going to create more harm because of that.
But doesn't it make a difference if that "acceptable yearly limit" is spread out throughout the year as opposed to a few minutes of CT scan session?
The dose required is actually quite a lot higher than typical comparisons to eg chest X-rays and the like
Gemini says this:
> A single typical CT scan delivers a dose that is roughly 1,000 to over 5,000 times higher than the dose you'd get from spending a few hours in Grand Central Terminal.
Where did you get that from?
Machine hallucinations are avoidable.
(And I'm not picking on the machine at all here. I use it all the time. At first, I used to treat it like an idiot intern that shouldn't have been hired at all: Creative and full of spirit, but untrustworthy and all ideas need to be filtered. But lately, it's more like an decent apprentice who has a hangover and isn't thinking straight today. The machine has been getting better as time presses on, but it still goes rather aloof from time to time.)
Commute through the Grand Central station everyday is certainly not a few hours.
And people don't tend to get a CT scan very frequently so the timeline here is massive.
CT Scan: 10-1000 mrem
Grand Central Station: 525 mrem / yr
https://files.eric.ed.gov/fulltext/ED297952.pdf
- Head CT: 2.0 mSv (200 mrem)
- Chest CT: 8.0 mSv (800 mrem)
- Abdomen CT: 10 mSv (1,000 mrem)
- Pelvis CT: 10 mSv (1,000 mrem)
So for a head CT, one would need to spend more than 13 hours per workday in the station. OP was off at least an order of magnitude.
https://www.epa.gov/radiation/frequent-questions-radiation-m...
In clinical practice, those doses are about 2-3x what I see on the machine dose reports every day at my place of work.
In thin patients who can hold still, I've done full-cycle cardiac CT and achieved a < 1 mSv dose. We are always trying to get the dose down while still being diagnostic.
Source: Practicing radiologist.
Also there's an apple store there. RIP all the geniuses there i suppose
I started taking ag1 and Metamucil and the stomach discomfort has completely gone away over a span of weeks/months.
The resulting dramatic improvement in sleep cascades to just about everything in my life and different recurring health problems keep disappearing now.
It’s crazy how many problems can be caused by apparently just not getting enough fiber.
Never ended up getting the CT scan, which probably would’ve been expensive and involve some small degree of risk.
Or the pre-x-ray technique of abdominal palpation.
I was just full of shit, as usual. Now I eat salads and drink more water when I am at elevation.
* a tablespoon of epsom salt * a tablespoon of mineral oil * several OTC products
What's interesting is I needed surgery to remove the most recent stones, and I've not had a CT-scan since- the urologist uses ultrasound.
On the other hand, I've had fluoroscopy.. probably worse than even CT-scans.
The risk from screening, and the risks from further diagnosis and accidental treating of false positives can be much higher than the disease itself as long as it is rare enough.
If CT scans are performed on more than 5% * (1 + false positive rate) of suspected cancer cases, having a CT scan in the history of 5% of cancer cases is entirely expected.
I took a preventative MRI run by an ML/AI company that the healthcare folks say is a bad idea. I didn't discover any hidden cancers but they did find 1-2 emerging health issues that were preventable with simple diet and lifestyle changes.
If everyone showed up to their doctor asking for preventative imaging, it would overwhelm doctors since there aren't enough resources to treat everyone who is sick. Your individual health will always be less important than the integrity of the system.
Sounds like the exact same results you'd have gotten without imaging.
You would have no idea you had it without imaging, since in the early stages you feel nothing.
Now I can work to build up muscle around that area and avoid over exerting that part of my back, instead of dealing with pain and being prescribed opiates in 20 years. Another example of how the system has killed countless people and absolutely failed the public.
From 30 years of age, disc degeneration is more likely than not. You don’t need a scan to tell you you’re in the early stages of it.
CT scanners don’t use magic non-carcinogenic x-rays.
Socrates is a man, men are mortal, Socrates is mortal.
We have the technology. We should have moved on to MRIs for nearly all scans years ago.
If you’re looking for a broken bone, take a single x-ray image instead of a whole CT scan, which is a far higher dose of X-ray radiation.
[1] See, e.g., https://zwangerpesiri.com/services/ct/ (no affiliation; just an example).
Why not use MRIs since they skip the problem entirely?
Don’t say cost or supply. That’s just because CT scans, misguidedly, have more demand. More demand for MRIs would unlock savings from scale.
https://radiographermedia.substack.com/p/x-ray-vs-ct-vs-mri
If what the reader cares about is the risk to them, why is the proportion of all cancers caused by CT relevant? If we found a way to prevent 50% of all other cancers would CT become higher risk?
Not if you fly decent distances a dozen times a year or more.
Of course, rationally speaking, I think at the individual level it's hard to really gauge this any more than any other residual risk factor. You could get very unlucky with cell damage from anything, more radiation just gives you more tickets to the lottery. I'm sure other factors play a role on an individual level and the risk to each person is not static.
[1]: https://pmc.ncbi.nlm.nih.gov/articles/PMC9447865/#:~:text=Pi...
CTs may not cause significant amounts of wrist/knee cancer - I can't speak either way on that - but that wouldn't mean they're 100% safe elsewhere. For starters, wrist/knee imaging needs less radiation - they're relatively thin parts of the body, and relatively small regions.
Move along...
CT scans are likely overused; my spouse has several chronic conditions and after receiving dozens a year for a while, we started asking if a CT was clinically indicated, or just precautionary. Mostly the response is "just in case". I wish EMRs did a better job of highlighting how many CTs someone's had recently for this sort of decision making.
There've also long been problems with kids getting unnecessarily high adult doses of radiation. My dad's a peds radiologist and was heavily involved in the founding of https://www.imagegently.org/.
Two weeks of physical therapy and I was fine.
At the time I was mad about the money, now I'm just thinking "what a dumb way to (maybe) get gut cancer."
I was young. I thought I was scheduled for an MRI like the one I had for my sinuses. I didn't even know what a was CT at the time.
Though when I asked they said it was like a long flight trip to aroynd the globe. While I don't believe that, I do believe that they are much more effective than they were 10+ years ago. Also I wouldn't have got my stomach surgery without my first one.
The Linear No-Threshold LNT hypothesis/model is still the fundament of all radiation protection theory and the modeling used in it.
The problem with using that is that since twenty years back we've known that both antioxidant activity and DNA-repair and protection mechanisms do not scale linearly.
Meaning that a more correct approximation of reality would be using a Non-Linear With-Threshold model.
But because our culture of permanent radiation hysteria we're paralyzed when it comes to changing the overarching guidelines, even when everyday practice have practically left it behind.
I guess a heart scan is about like six months of natural background radiation according to this chart.
https://www.radiologyinfo.org/en/info/safety-xray
My father’s side has a history of heart attacks, so I’m trying to avoid that fate and consider the risks worth it.
Also, ionizing radiation has a varying risks to different tissues. "Soft" tissues that have cells that divide a lot (lungs, colon, etc) are of greater risk than others. I wouldn't bat much of an eye for a CT scan on my knee, but would be more worried about a chest procedure. Again, more worried doesn't mean I wouldn't do it, as the alternative is either a much more expensive MRI, much more fuzzy echo-cardiogram, or wondering if my health is more seriously at risk.
The science is based on assumptions and extrapolation, they drew a linear plot line between rates of cancers at different levels of radiation, and then extended it down and to the left. But there is no actual experimental data showing a relationship between low dose radiation and cancer (Ironically there IS evidence that rates of overall cancers are lower in high altitude cities like Denver with more background radiation).
It's a shame our medical systems invested so heavily into CT machines at the expense of MRI's
In practice a CT machine is also a much better workhorse for innumerable tasks that are very hard to effectively investigate with an MR machine, as MR imaging takes significantly more time, and requires more technical knowhow among the medical staff involved.
Considering the health and life expectancy in Japan, I call BS.
And yeah of course it's multifactorial. It'd make more sense to look at cancer data specifically, but I don't have that at hand. However, cancer is a leading factor in lifespan limits…