A fiducial marker for use in a gamma-guided stereotactic localization system for imaging a suspected cancer and guiding a physician in the removal of tissue samples for biopsy. The fiducial marker includes a fiducial source that can be accurately located in a positioning system and used to correlate the location of the positioning system with the detector and therefore the region-of-interest. The fiducial can be made radioactive such that it can be seen by the gamma camera. The fiducial marker enables the accurate positioning of other hardware in proximity to the object to be viewed.
