37-y-old woman with HER2-positive ductal breast cancer (4.9 × 3.1 cm). (A and B) Baseline 18F-FDG PET (A) and fused 18F-FDG PET/CT (B). (C and D) After 2 cycles of carboplatin, docetaxel, trastuzumab, and pertuzumab treatment, significant reduction in tumor 18F-FDG uptake, from SUV of 16.1 to SUV of 1.6, was seen on 18F-FDG PET (C) and fused 18F-FDG PET/CT (D). Histopathology at completion of treatment showed minimal residual disease in tumor bed.