A patient with diabetes has a red, hot, swollen great toe three weeks after a puncture wound, and the physician must choose between antibiotics alone and a bone biopsy. Only one appointment is available tomorrow, and the finding must separate soft-tissue inflammation from actual bone involvement. Which bone imaging protocol best answers this osteomyelitis question?

A three-phase bone scan answers the question by showing three physiologic stages after injection. Flow images track tracer arriving at the area and reveal increased blood supply; blood-pool images minutes later show hyperemia and soft-tissue inflammation; delayed images a few hours later show osteoblastic uptake in bone. Bone infection typically produces focal increase on all three phases compared with the opposite foot. Soft-tissue inflammation can increase the early phases while causing only mild or diffuse delayed change, helping you distinguish it from bone involvement. A whole-body scan from skull through feet surveys the skeleton with delayed coverage but omits flow and blood-pool images, so it is useful for skeletal survey rather than this acute distinction. Delayed static spot images of both feet also provide only the late picture, without vascular or pool information. SPECT provides cross-sectional localization of increased uptake, but without early phases it cannot separate soft-tissue hyperemia from bone uptake. Exam caveat: a neuropathic diabetic foot can make the result equivocal, and labeled white-cell imaging may be added if the three-phase study is unclear. Practical check: before the appointment ends, confirm that flow, blood-pool, and delayed images of both feet are on the worklist.