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Comment by toomuchtodo | Hacker News Reader

How many CT scans must someone get before its more detrimental that having the cancer go undetected?

EDIT:

http://www.cancer.gov/cancertopics/factsheet/detection/CT

"In addition, whole-body CT can expose people to relatively large amounts of ionizing radiation—about 12 mSv, or four times the estimated average annual dose received from natural sources of radiation. Most doctors recommend against whole-body CT for people without any signs or symptoms of disease."

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I have read that there is no such thing as a harmless amount radiation when it comes to the dosage you get from a CT scan. Every scan increases your risk. I think my impression is that many doctors think there must already be a health problem in the patient that needs to be addressed before someone is subjected to a CT scan. That is use a CT scan when you know it will help, not when you don't know.

> Every scan increases your risk

That is technically true, but it's also true that every banana you eat adds to your risk. At some small percentage increase in risk, it's sensible to stop caring.

I don't know the answer to that, but I know that some people are taking full-body CT scans annually or bi-annually because of fear of cancer.

This is a great way to help increase the risk you get cancer, since it's cumulative, not per-instance.

>This is a great way to help increase the risk you get cancer, since it's cumulative, not per-instance.

Well, I suppose at least in their case it has a high probability of being detected within 6-12 months.

I know, but that proves that cancer scares people to the point of doing silly things. An innocuous screening test, even with a fair amount of false positives could be a huge win.

Are you sure it's CT scans? Why not MRIs, which as far as we know cause much less harm to the body? (They're more expensive, but I'd think people who are that worried about cancer would consider the extra expense worth it.)

CT vs MRI comparison: http://blog.radiology.ucsf.edu/neuroradiology/exploring-the-...

It's brain specific, but I assume it translates to whole body as well.

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