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."

That's if you're going through insurance. They'll scan anyone with a check in their hand.

nope, some will reject. I had to go through 3

There are probably other imaging centers in your region.

CAT scanners are of variable cost and resolution.

Yes, what's your point? A CAC test doesn't require the most expensive CT scanner.