Had hida scan for gallstones & months later multiple mammos for stereotactic biopsy (calcification-benign)-dangers to all this radiation?

The danger is tiny: The risk of induced cancer from a HIDA scan and dozens of mammogram images is incredibly small. In fact, some would claim the risk could barely be calculated reliably. See: http://www.riainvision.com/exams/hida_scan.aspx Note, we all get x ray radiation naturally every day. There is real risk with repeated studies such as CT scans. For instance, one CT study of the chest equals 100 chest x rays.