Hank,

The radiation keeps working for up to three weeks. Its the healing that may be throwing you. If you are looking at a PET scan for signs that the cancer is still active, you have to wait three months. This is because healing cells look very much like cancer cells in a PET scan and the healing from the radiation and chemo can take up to three months. Thus the healing cells may give you a false positive for cancer.

My doctor just let me know that they would be doing a CT on me about 6 weeks out but will wait a full three months before taking a PET scan.