Described herein is the use of gamma cameras in the fringe field of the MRI system. Specifically, an MR image of the breast with lesion identification is first produced. Then, a gamma camera is attached to the existing breast immobilization system for generating one or more gamma images of the breast. The gamma camera is then removed from the breast immobilization system, and a breast biopsy is performed. The gamma camera can then be used to image the biopsy cores that have been removed from the patient in order to verify that the biopsy cores are radioactive, that the biopsy cores extend from one end of the lesion to the other and have a radioactive profile in which the tip is not as radioactive as the middle, and in which the ratio of amount of radioactivity in the middle of the core to the amount of radioactivity that is present in the tip of the core can be expressed as a ratio.