FIGURE 3.  PET/CT defines whole extent of recurrence in areas with complicated anatomy showing changes after treatment. A 46-y-old woman with breast cancer, after right mastectomy 9 y ago, presented with local recurrence and was referred for PET/CT study for treatment planning. (A) ¹⁸F-FDG PET study (coronal slices) demonstrates area of intense ¹⁸F-FDG uptake in right breast, consistent with known local recurrence. Additional small focus of slightly increased tracer uptake is seen in anterior chest wall (marker). (B) Transaxial slices at level of this equivocal ¹⁸F-FDG focus on PET (left) show that focus is localized by PET/CT (center) to lymph node in right internal mammary chain (9 mm in diameter), retrospectively identified on CT (right). After these PET/CT findings were obtained, patient was started on hormone therapy with aromatase inhibitor letrozole (Femara; Novartis). On basis of PET/CT findings, radiotherapy was planned to include internal mammary chain, in addition to irradiation of axilla and supraclavicular fossa. After completion of external radiation, patient received ¹⁹²Ir brachytherapy implant. At 30 mo after therapy, patient was without evidence of disease, and PET/CT results were negative.