Brain mets/scar tissue

Hi,
The brain MRI has shown that the lesion has grown but it could be scar tissue. It is hard to tell w/o a biopsy. My Dr. would like to have a craniotomy so that we remove the scar tissue and not take any chances. I have been NED elsewhere for over 5 years but continue to fight brain mets. I am to get a brain PET and a brain MRI with profusion next week. Cancer sucks!