If you want a CAC scan you can just go directly to an imaging center that offers it and order it yourself. It doesn't require a prescription. In most cases it won't be covered by insurance for screening purposes.
Wow, I would have expected something like this to be $thousand$ but a quick check with AI claims that in the U.S. the self-pay rate is anywhere from $100-$400. Still not cheap, but much more affordable than I expected.
It varies. At the largest medical provider in my region they stipulate "To self-refer for a Heart Scan, you must be male between the ages of 40-65 or female between the ages of 45-70 and have a qualifying risk factor."