The conversation between human and AI assistant.
[|Human|] Hello, After being in remission from breast cancer for 20 years, it has now returned as a tumor in the sternum area of the chest. This recurrence was in May 2010. I was put on the drug Femara. I am concerned about the PET scans (Im having my 3rd one next week) and the CT scans that are periodically ordered by the oncologist. How much radiation is too much? And what steps can I take prior to these tests to best protect myself from overexposure?
[|AI|]  Thanks for your question on Chat Doctor. I can understand your situation and problem. PET scan is having the highest radiation exposure. CT scan is also having higher radiation but less than PET scan. Permissible PET scan exposure is once in six months. And for CT scan it and once in two months. Anything more than this will cause radiation injury. To prevent radiation injury you should follow these steps. 1.  Chat Doctor. 
