I'm not sure how this thread got on the topic of mastoid inflammation, as it normally relates to those who have had inner ear tumors, both benign and malignant. The malignant ones are relatively rare when compared to all other types of tumors. Mastoid inflammation is relatively common and its primary causes are mostly benign. Inner ear tumors are extremely dangerous as they are close to structures such as the base of the skull, which when penetrated allows the tumor access through the dura to the brain itself. As to the PET showing increased metabolism in an area which has been radiated in recent history, I do not think that this is unusual as the healing process continues for some extended time after the end of treatments, and it would certainly show up as increased sugar consumption by those cells. A secondary scan compared to the original, even if only 3-6 months apart, will offer the diagnostician a comparison trend, determining if things are toning down or stepping up. Getting scans immediately after treatment is common, and not only establishes the impact of the treatment itself, but provides baseline information for all future scans of that area. Both MRI's and CT's are useful especially when done with contrast as each one has it's own strengths in revealing issues in either soft or hard tissues. The use of a combined PET/CT is realtively new, but shows information which either scan alone fails to paint in full. See the news article awhile ago in the OCF news section on the combined scanning technique. http://www.oralcancerfoundation.org/news/story.asp?newsId=32

Brian, stage 4 oral cancer survivor. OCF Founder and Director. The first responsibility of a leader is to define reality. The last is to say thank you. In between, the leader is a servant.