Also known as stereotactic localization biopsy; a technique that uses X rays to guide the needle for a biopsy of a mass in the breast that cannot be felt. Stereotactic breast biopsy takes X rays of the breast from two different angles. A computer plots the exact location of the area where there is a suspected lesion. When the target area is clearly identified, a radiologist can position the apparatus that holds the needle and advance the biopsy needle into the lesion.