Bone Scan follow-up

• Correlate with anatomic imaging (XR, CT, or MRI) of the site.
• If indeterminate, consider SPECT/CT or targeted MRI before treatment change.
• Single lesion in spine/pelvis without correlate → MRI to exclude early metastasis.

Source: SNMMI procedure guideline

• Random distribution involving axial and appendicular skeleton supports metastases.
• Oncology referral; baseline scan recommended before systemic therapy for response assessment.
• Consider PSMA PET (prostate) or FDG PET when bone scan is equivocal.

Source: SNMMI / EANM bone scintigraphy guidance

• Diffuse skeletal uptake with absent/faint renal activity — diffuse marrow involvement.
• Common in widespread prostate or breast metastases; correlate with PSA, ALP, CBC.
• Differential: metabolic bone disease (renal osteodystrophy, hyperparathyroidism).

Source: SNMMI consensus

• Transient increase in uptake 2–6 months after initiating effective therapy.
• Reflects osteoblastic healing — do not interpret as progression in isolation.
• Re-image at 6 months or correlate with CT/labs before changing therapy.

Source: PCWG3 / SNMMI guidance

• Linear/focal uptake at single rib most often reflects healed or healing fracture.
• Correlate with history of trauma and chest XR/CT.
• Multiple rib uptake in linear distribution → consider trauma vs. metastases by morphology.

Source: ACR Appropriateness Criteria

• Focal fusiform uptake along long bone cortex (tibia, metatarsals, femoral neck).
• MRI is preferred for early diagnosis and grading; bone scan remains highly sensitive.
• Sacral H-pattern (Honda sign) → pelvic insufficiency fracture, evaluate for osteoporosis.

Source: ACR Appropriateness Criteria

• Intense uptake involving entire bone with expansion (pelvis, spine, skull, femur).
• Correlate with elevated alkaline phosphatase and characteristic XR/CT changes.
• Treatment with bisphosphonates if symptomatic or at risk for complications.

Source: Endocrine Society / SNMMI

• Osteomyelitis: increased uptake on all three phases (flow, blood pool, delayed).
• Cellulitis: increased flow/blood pool but normal delayed bone uptake.
• In post-surgical or diabetic foot, add WBC scan or MRI for specificity.

Source: SNMMI infection imaging guideline

• Degenerative joint disease, healing fractures, and Paget disease are common pitfalls.
• Correlate with XR or CT before recommending oncologic workup.
• Symmetric periarticular uptake favors arthropathy over metastasis.

Source: ACR Appropriateness Criteria