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?".
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?
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.
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.
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.
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.
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.
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.
> 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.
Someone I know got partial constipation, lack of apetite and stomach reflux. After some month of triying to fix the reflux, they discovered it was intestine cancer when the cancer was big enough to block almost all the flow.
IIUC from a sibling reply, you already used a few laxative, so perhaps a CT scan was the next step.
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.
But did those words really get through to you like an energetic photon? I think, it's quite ionic how frequently the last strand has to break before we realize, we should have been radicalized by people, not high voltage discharge events.
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.
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.
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.
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.
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.
"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.
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.
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.
The comments on that article heavily criticized that portion. I don't know jack about the topic, but it really did seem like just Scott's envelope-math against the sentiment of the entire field: "this is not enough radiation to matter".
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.
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).
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.
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.
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...
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.
Readit News
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.
Dead Comment
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?
IIUC from a sibling reply, you already used a few laxative, so perhaps a CT scan was the next step.
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.
Beats any processed supplement or other OTC drugs IME.
* a tablespoon of epsom salt * a tablespoon of mineral oil * several OTC products
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.
I imagine the doctor already assumed the shit was there, but wanted to understand why.
I further imagine prescribing a megadose of laxative might be harmful if someone cant expel the shit.
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.
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.
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).
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.
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.
[1] See, e.g., https://zwangerpesiri.com/services/ct/ (no affiliation; just an example).