DR Wang thank you so much for your time!
Sorry you had to go through all that. All these imaging studies are performed with risk/benefit in mind...you needed that to figure out what was going on and to save your life. As for exactly how much, that is hard to figure out because it is dependent on what kind of scanner was used and how they scanned, but plenty of people have had those kind of scans over time. As for what can be done about it now, your body naturally repairs damaged DNA. There is nothing we can do about it as doctors to help or repair it, unfortunately. Best thing from now on out is to bring up your history if other imaging opportunities come up. Try to steer clear of CT in favor of MRI and US (modalities that don't use radiation). But even so, sometimes CT will still be the better study. Just keep a dialogue open with your doctor and radiologists.