Zr-DFO-pertuzumab (89Zr-DFO-pertuzumab) PET/CT will be performed in patients with known HER2-positive malignancy. Patients with multifocal disease, as demonstrated on cross-sectional imaging studies, will be preferentially recruited.

Zr-DFO-pertuzumab studies will be performed as hybrid PET/CT examinations with known HER2-positive malignancy

Patients will be monitored closely for evidence of adverse events, including vital signs before and after tracer administration. The day after tracer administration, a physician will screen for any side effects requiring treatment. If a severe adverse effect (Common Terminology Criteria for Adverse Events grade 3 or 4) attributable to 89Zr-DFO-pertuzumab occurs in any patient, then further use of 89Zr-DFO-pertuzumab will be suspended and the protocol reviewed with the MSKCC Data Safety Monitoring Committee.