Figure 12xy. FDG uptake in bone marrow in a patient treated with granulocyte colony-stimulating factor. Axial FDG PET images (shown from superior [top left] to inferior [bottom center]) and a sagittal FDG PET image (bottom right) show intense FDG uptake in the vertebral bodies and sternum. The intense uptake resulted from expansion of the bone marrow due to the granulocyte colony-stimulating factor. Marrow activity in the ribs, scapula, and proximal humeri is also evident.