OUTLINE: This is a randomized study. Patients are randomized to one of two diagnostic arms. Arm I: Patients undergo radiographic placement of a radioactive seed (either iodine I 125 or palladium Pd 103) into the suspicious lesion. Patients then undergo surgery to remove the lesion along with the seed and a small margin of surrounding breast tissue followed 3 months later by a postoperative mammogram. Arm II: Patients undergo a needle localized breast biopsy with a specimen x-ray.