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.
There are probably other imaging centers in your region.
That's if you're going through insurance. They'll scan anyone with a check in their hand.