[joshgel]

The problem is when you are screening lots of people, most of whom don't actually have cancer. The individual risk is low, but the population risk is high. And when we talk about cancer screening we have to think at the population level.

[488643689]

From what I know, the risk is not high enough to leave a strong signal. The problem is the overall high cancer rate for humans. As far as I know, we still don't have a model for predicting cancer rates after low exposure to ionizing radiation.

[hylaride]

OK, but you'd be delaying scans by having to wait for the MRI, which takes significantly longer to setup and administer as well as being much more expensive (which would further reduce access).

Also (and this is according to the XKCD chart) you'd need 50 CT head scans before you'd hit the clear statistical cancer risk.

But it's not like the whole population gets a CT scan every year, or even during their entire life. If you need one anyways, there's probably a more pressing issue that 1/50th the clearly statistical risk level.