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by anon4lol 2809 days ago
As someone who has had several CT scans (and paid for CT scans), the idea that a CT scan is better than a physician feeling your abdomen is absolutely ridiculous. Pumping contrast agents into everyone who has pain is a very bad idea. Moreover, enforcing decisions by algorithmic rules is problematic, especially considering who might be making those decisions.
2 comments

Can't resist to at least provide some response here.

1) Having CT scans, and paying for them, does not really objectively lead to the conclusion that followed. Let's feel that tumor inside your lungs.

2) CT scans can also work without contrast agents. In addition they typically do not register everybody for a CT scan nor pump them full with contrast agents. There is a process. In US some hospitals are trigger happy as they get paid per case, blame the system not the technology. If anything an algorithm will fix that nasty human behaviour.

3) Having biased humans enforce decisions is not always a guarantee for success either. Every human sees only a fraction of the total amount of cases an algorithm processes within seconds. There are several fields where AI already outperforms elaborate test panels of MDs. Though it is hard to introduce these algorithms for the same reasons Tesla is having issues. Who is responsible when a mistake is made?

3.1) you would be amazed how often MDs do not agree when the same problem is put in front of them. 50/50 and 60/40 are very common cases. AI is typically more in the 80/20 90/10 range which is a huge improvement.

Now, all of this does not mean we do not need MDs anymore. An important aspect often neglected due to time bounds is the interaction of a patient with the doctor. With algorithms saving time more could go to the patient. That's a win.

Plus radiation. Every CT scan increases your odds of cancer.

Also, mammography or even colonoscopies have been proved for most of the population to do more harm than good. cochrane is full of meta-studies about it.

The medical industry is very shady.

> Every CT scan increases your odds of cancer.

There is no evidence for that statement. More specifically, there is no evidence that a single radiation dose below 100mSv is harmful at all, but plenty of evidence (Taiwanese radioactive apartment buildings, nuclear navy worker study) that it isn't. Muller made it up for political reasons.

There is evidence:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3660619/

> Title: Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians

> Conclusions: The increased incidence of cancer after CT scan exposure in this cohort was mostly due to irradiation. Because the cancer excess was still continuing at the end of follow-up, the eventual lifetime risk from CT scans cannot yet be determined. Radiation doses from contemporary CT scans are likely to be lower than those in 1985-2005, but some increase in cancer risk is still likely from current scans. Future CT scans should be limited to situations where there is a definite clinical indication, with every scan optimised to provide a diagnostic CT image at the lowest possible radiation dose.

And about "a single radiation dose": As soon as you get a CT the chances that you will have only a single one in your life are greatly reduced, because you just had that one. So it still is better if the count remains at zero, or your precondition can easily be invalidated.

The problem with that study is that "people who take a CT scan" is not exactly an unbiased sample of the general population.

Now compare this to

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2477708/

> only a single one in your life

"A single dose" as in "a discrete event". Another single dose the next month is (probably) harmless again. Cells react to radiation with repair mechanisms, and once that activity subsides, the event is over.

Radiation exposure isn't linearly cumulative. The argument that it is was made before we even knew the structure of DNA! Today, we know better.

I also recommend at least the "Conclusion" section of this document, selected as an example, not as the one definite document: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3611719/ It is a good read overall too. You make it sound as if it does not matter. Apparently that is not the general medical opinion.

I also don't see what the problem with the selection of people is supposed to be. Those selected are more likely to not be able to repair DNA damage? I think this particular selection makes no difference for the purpose.

Overall, OP said "there is no evidence" and it seems that yes, there is. What you think of that evidence is not the question, OP had said there isn't any. When I look at the actual recommendations it seems that most medical people don't think so, after all, the recommendation still is to limit the radiation exposure, not just for the frequently exposed (radiation workers) but also for those one-time patients.

Even on a per-event basis reducing the amounts of radiation was and is a major design goal for the devices. Does not look like those who are involved in all of this think there is no problem.

> Overall, OP said "there is no evidence" and it seems that yes, there is.

This is evidence for a correlation between the number of CT scans and cancer incidence. To jump to the conclusion that the cancer is caused by the radiation from the CT requires a leap of faith.

The funny thing is, if an epidemiological study shows that low dose ionizing radiation is beneficial (radioactive apartment buildings, nuclear navy workers), it's dismissed by a completely ad-hoc "healthy worker effect" or "healthy student effect". But in a study of people who received a CT scan, where you should expect a "sick people effect" (healthy people don't get CT scans), you "don't see a problem".

This study is solely focused on childhood and adolescence CT scans. Any radiation dosage you take during childhood has magnified effects.
Thanks for pointing that out, but, okay, children and adolescents count too?

OP responded to a specific comment, I responded to OPs comment. I don't understand your point in that given context. I'd think showing one study - I didn't bother to look any further - that shows a risk was sufficient.

Since even adults have plenty of still dividing cells left I see it as reasonable to assume that adults are at risk too, even if that will likely be lower.

I also recommend at least the "Conclusion" section of this document, selected as an example, not as the one definite document: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3611719/ It is a good read overall too.

I don't remember the exact number but when it comes to cancer risk increase getting a regular 100 mSv x-ray as a kid counts something like 10 xrays of an adult done one after another( i.e. single dose). That's because any mutations that happen will stay with you for the rest of your life plus propagate to a lot more cells in total as your body is still growing. So while an important topic for some specialties it would be wrong to make broad statements based on this.
>>Plus radiation. Every CT scan increases your odds of cancer.

If the doctor makes money from your CT Scan you are absolutely right to question the need. Conflict of interest and all. Sure you increase the chances of cancer but that has to be weighed by what can happen if you don't do the CT Scan.

You also need to balance what happens if you do have the scan too.

Over-testing leads to over-diagnosis, and that can be harmful.

Very few modern insurance plans pay per procedure and that will be done away with entirely as time goes on. Typically physicians are paid a flat rate per patient or a flat rate per diagnosis with a complexity multiplier. This creates an incentive to NOT perform imaging unless it's necessary.
In what country? The US is still mostly per per procedure. There are codes for procedures and for diagnoses and they both get factored into the bill.
Take a look at DRGs. In the US they were first used for payments in the Medicare system but they have expanded outside that program over the years:

https://en.wikipedia.org/wiki/Diagnosis-related_group