Hello, I understand your concern, and it is very common to worry about radiation exposure. A single CT scan of the brain typically delivers about 1–2 mSv of radiation. You have had two CT scans in your entire life, one at age 8 and one at 18. This is considered very low cumulative exposure. The average person is exposed to ~3 mSv of natural background radiation every year from the environment. Your total lifetime CT-related exposure is roughly equal to a few years of natural background radiation. The risk of developing brain cancer from two CT scans is extremely low. Large studies estimate the added lifetime cancer risk from a single head CT to be less than 0.01%. With only two scans spread over 10 years, the risk remains negligible and close to zero. There is no evidence that two head CT scans cause brain tumors in otherwise healthy individuals. Your recent CT scan is normal, which is very reassuring. There is no need for any special tests, follow-up scans, or cancer screening because of these CT scans. Only seek medical evaluation if you develop new or persistent symptoms such as: Progressive headaches Seizures Persistent vomiting Weakness or vision problems Otherwise, you can live a normal, healthy life without fear related to these CT scans.