F-18 FDG PET/CT findings in postradiation pelvic insufficiency fracture.

We retrospectively identified eight patients who underwent F-18 FDG PET/CT and had diagnostic findings of postradiation pelvic insufficiency fracture. The fractures had a median SUV(max) of 2.5 (range, 1.6 to 6.0) and were initially interpreted as possible metastases in six patients. A new bone lesion developing in the sacrum, pubic ramus, or acetabulum after radiation for pelvic malignancy is likely to be a postradiation pelvic insufficiency fracture, even if associated with increased FDG uptake at PET.