An Investigational Scan (64Cu-DOTA-Trastuzumab PET/MRI) in Imaging Patients With HER2+ Breast Cancer With Brain Metastasis

This clinical trial examines an investigational scan (64Cu-DOTA-trastuzumab positron emission tomography \[PET\]/magnetic resonance imaging \[MRI\]) in imaging patients with HER2+ breast cancer that has spread to the brain (brain metastasis). Diagnostic procedures, such as 64Cu-DOTA-trastuzumab PET/MRI, may help find HER2+ breast cancer that has spread to the brain and determine whether cancer in the brain takes up trastuzumab, which may predict for response to trastuzumab deruxtecan (the standard of care chemotherapy).