This is a part one dose-determining study followed by a part two study. PART ONE: Patients are randomized to 1 of 3 dose levels. Patients undergo a PET scan 24-48 hours after injection of 64 Cu-DOTA-trastuzumab. PART TWO: Patients undergo a PET scan 24-48 hours after injection of 64 Cu-DOTA-trastuzumab at the optimal dose as determined in part one of the study.