Posted by pseudolus 4 days ago
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
- 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
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.
1: You won't find relative net survival above 100% in the CDC's statistics. That's because they calculate survival rates using daily differences in death hazards derived from life tables of people with cancer and those without. Add up the differences across all days, do some exponential math, and voila: relative net survival rates. But, if the relative risk for a day is negative (i.e. those without cancer have a higher risk of death), then they set the relative risk to 0 instead for that day. Which is ridiculous, IMO. It's forcing a distribution of actual events to match an idealized model.
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.
This video [1] is a presentation on bowel CT with great images. For those interested in X-ray, compare the X-rays at 14 minutes with the CT at 10.
Also worth noting, that X-ray is being recommended as a quick diagnostic before moving to CT
After all, if you have the tiffs, you already know the grayscale for every pixel in the XYZ space. You just need to grab the right pixels from each slice
I had assumed slicing the raw beam data would give you much better output resolution whenever there were differences between transaxial and z resolution, since at some angle and offset you end up sampling across the largest gaps in the XYZ pixels. But maybe that's not a real issue? Is this how it's done in practice?
I was just full of shit, as usual. Now I eat salads and drink more water when I am at elevation.
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.
Everyone is going to get a bad back at some point if they don't take care of themselves.
"Eat right and exercise " is very generic advice, but it's cheaper than an MRI and will prevent more disease.
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).
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.
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?
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.