No, of course I'm not worried, I think it would be great....
I am truly stunned by this. A self-interpreted home-made CT scan is an unalloyed good? Notwithstanding the radiation to get there, without serious testing, you have no idea how accurate the thing is (back to the FDA's repeated requests to 23andMe).
Allowing the heroic assumption that the Garage-scan-o-matic things actually give accurate results, are you also saying you think the majority of people have the education and knowledge to make heads or tails of what might a slightly larger appearance of the brachiocephalic artery might mean for them? Or that they have any idea what to do about it?
Are you going to try to pass laws against skin, testicle, and breast self-exams because people might be confused by the lumps and spots they might discover?
That's not what I propose nor what the FDA is doing. If someone tries to sell an automated system to tell people what those lumps and spots mean (particularly if they use the term "risk") you'd better believe I would demand enforcement of the existing laws that say that the seller must prove that their system works in order to sell it.
Some doctors do, others are dumber as dirt.
Sure, doctors are people and there are all kinds of them. But at the very least they have had a rigorous education, and following that a series of experiences in trying to understand the confusing mishmash of information about people's health conditions and make judgments about a course of action to follow.
Since this post is entitled "offensive arrogance", let me just ask if you really think that education and experience means nothing. And if so, does it mean nothing when an engineer used his or experience to say a piece of software is poorly architected, or that car can be hacked, or there is inadequate review of security? After all, I can read Slashdot to get the answers I need or check something out from github to fix the problem...
There is a role for experts and there are some things that are dangerous enough that an expert's opinion should be required, whether that's a doctor, an engineer, or policeman.