Are my doctors wrong for doing this?

In the past 6 months, I have had about 6 CT scans of various parts of my body. I have a (benign) brain tumor and cyclical cushing’s disease and my doctors insist that these scans are necessary in order to get the correct diagnosis, treatment protocol, etc. I am very worried about the risks from being exposed to the radiation emitted during one of these scans. I get varying answers from anyone I ask, ranging from no, the risk of cancer from x-rays is quite low.. to “getting two or three CT scans of the abdomen expose you to the same amount of radiation as people who lived near the atomic blast that ravaged Hiroshima…” Obviously, when I hear that… it freaks me out. I’ve had TONS of CT scans in my lifetime. I am also a cancer survivor and I’ve been exposed to high-dose radiation from my treatment. Am I a ticking time bomb? I feel now that I’m bound to get cancer again. Should I refuse more of these tests?