Didn't know how dangerous head cts were. 15-20 lifetime, 10 in past ten years, some w/ contrast. 1or2 cta. what cancers am i at risk? how high risk?

Low cancer risk: I can only estimate your exposure because it is dependent on the way the tests were done and your body size. More importantly is why the test was ordered. Both you and your doctor should consider the risk and benefit of each test. Did you talk to your doctors about this? Chances are that a test was important for your care and the risk was consider less than the need. see attached chart