PET scans map metabolic activity, so they can detect abnormal bone activity—such as cancer metastases, infections, or healing fractures—by showing increased radiotracer uptake. However, PET alone doesn’t provide detailed bone anatomy; CT or MRI (often combined with PET as PET/CT) is used to visualize bone structure and precise location. Interpretation uses both metabolic and anatomic images.

PET scans measure metabolic activity, not bone structure, so they’re not the best test to detect most fractures. Acute fractures can show increased uptake on PET because of inflammation and healing, which might be seen incidentally or mistaken for disease. For evaluating suspected fractures, plain X‑rays, CT, MRI or a bone scan are preferred depending on the location and timing.

MRI is the preferred imaging test to detect and characterize suspected bone cancer because it best shows bone‑marrow involvement and soft‑tissue extent. Plain X‑rays are usually first‑line; CT defines cortical bone detail. To look for spread, a bone scan or PET‑CT is used. Definitive diagnosis requires a tissue biopsy reviewed by a specialist.

Doctors order PET‑CT scans to assess tissue metabolic activity alongside anatomy, commonly to detect, stage, and monitor cancers, find metastases, or check for recurrence. They also evaluate treatment response and guide radiotherapy planning. PET‑CT can assess myocardial viability in heart disease, localize seizure foci or neurodegenerative brain changes, and detect sites of infection or inflammation.

Yes. CT scans provide detailed cross-sectional images of bone structure, detecting fractures (including complex or occult ones), dislocations, bone tumors, infections, and degenerative changes. They offer higher resolution and 3D reconstructions for surgical planning compared with plain X‑rays, though MRI is better for bone marrow and soft-tissue assessment. CT uses ionizing radiation, so it's used when benefits outweigh risks.

PET scans can miss small lesions under 5–7 mm and cancers with low glucose uptake: well‑differentiated neuroendocrine tumours, many low‑grade prostate cancers, mucinous adenocarcinomas (ovary, colon), lobular breast cancer, some slow‑growing lung subtypes (adenocarcinoma in situ), and lesions masked by urinary tracer in bladder or urinary tract. False negatives also occur in very early disease.