[wyldfire]

> I don't think many doctors recommend this for the general public

> A CT scan comes with a strikingly high radiation dose

Another challenge is that they probably wouldn't give you a baseline scan from the bottom of your toes to the tip of your head. Abdomen/thorax and/or head/neck, probably. So you can't get the whole skeleton. A planar "scout" scan of two dimensions is normal examination procedure prior to the diagnostic scan. Those can often run a long portion of the body. You might be able to project something from that.

Aside: The Sievert (SI unit referenced in the XKCD comic) is a really interesting (IMO) unit. Instead of measuring the radiation in normal "amount of radiation" style, it measures the "equivalent dose" intended to help understand the ultimate biological impact of the radiation. The radiation emitted might be measured in Joules and the radiation absorbed might be measured in Gray (Joules/kg), but Sievert can be weighted by the tissue that absorbed the radiation. Your gonads or your head would have a greater weight than your ankle (or so I figure). This, I would guess, gives radiologists a much better way to consider the net impact of a diagnostic procedure in order to weigh against the overall diagnosis & prognosis.

Also, another aside: dose has become a more competitive feature for CT manufacturers in the last decade or so and several offer features to measurably reduce the dose.