Study of 111In-DAC as a Medical Imaging Agent for the Detection of Breast Cancer

Inclusion Criteria Patients will be eligible for the study if they: * Are non-pregnant, non-lactating females 18 years of age or older(must agree to use an appropriate and effective method of birth control during the study and for 2 weeks after study) * Are being evaluated for a known or suspected breast tumor (must present with either a mammographic abnormality 10mm or larger or a mammographically occult but palpable abnormality of the breast) * Have been previously scheduled for biopsy or surgical excision of the known or suspected tumor of the breast * Have signed an informed consent form Exclusion Criteria Patients will not be eligible for this study if they: * Have a history or suspicion of significant allergic reaction or anaphylaxis to any of the 111In-DAC components * Have a clinically unstable medical condition or opportunistic infection, a life-threatening disease state, impaired renal or hepatic function or are immunosuppressed * Are taking or have taken part in any investigational study within 30 days of start of study * Have received an indium agent within 30 days of start of study * Are not able to remain immobile during scanning time * Have taken drugs that may damage the kidneys within 2 weeks of start of study * Have abnormal laboratory test results: hemoglobin \< 9.5 gms/dl, serum creatinine \> 1.5 mg/100ml, alkaline phosphatase 2X the upper limit of normal * Have undergone an excisional and/or needle localization biopsy within 4 days prior to start of study