I'm sorry to hear about your Mom. As for PET scans and brain scans being different its all about metabolic activity. A pet scan measures how much glucose (sugar via the liquid she drank prior to the scan) was absorbed throughout body. An active tumor will "suck up" significantly more sugar than any other part of the body except for the brain. Your brain is constantly active and will absorb lots of the sugar solution therefore masking any tumor in the brain hence a seperate brain scan (usually a CT scan) to locate possible lesions. I hope I've been of some help. Good luck.
JT
Hi,
The PET scan would tell us about the metastasis to other organs in the body and a brain scan would tell about whether there is brain metastasis or not and its extent.
You should discuss this in detail with your doctor too, this would alter the plan of management to some extent depending on the results.
Regards.