Figure 1b. Residual mass with FDG uptake in a 76-year-old woman with non-Hodgkin lymphoma who had completed chemotherapy. (a) Chest CT scan shows residual soft-tissue attenuation in the mediastinum and right hilum. (b) Corresponding axial PET scan shows residual FDG uptake in the same location. The patient underwent salvage chemotherapy, but tumor relapse occurred.