The stereotactic biopsy is a lengthy procedure; 30-40 minutes depending on the location & ease of finding the tissue. I was able to sit up, some folks lay down. So in the process of a mammogram (imagine the squeeze) multiple needles are inserted in the breast at the same time. One for anesthetic, one to insert a titanium chip so a surgeon can locate the tumor, one to extract the tissue. The latter two are large needles. It hurt more than anything I’ve experienced except childbirth which I did w/o meds or an epidural. I was sweating and tears streamed. I used deep breathing to stay calm. Two techs held each hand and the radiologist was phenomenal with information & encouragement.

I hope this helps you prepare rather than be afraid. I think my experience is fairly typical.