Bone scintigraphy is one of the most common nuclear medicine investigations. The investigation is particularly useful because images of the skeleton can be taken from head to toe, or back to front, by a relatively simple procedure.
The investigation is highly sensitive for showing unhealthy processes in the skeleton but the specificity is proportionately low. It is especially sensitive for active, sclerotic tumors.
- Small, osteolytic tumors, metastases, especially in plasmacytoma, but also in malignant melanomas, kidney cancer, and thyroid cancer, can be overlooked
- For bone pain and “negative” bone scan, an MRI should be performed
- In patients with treatment response from bone metastases, one will usually see an increase in uptake of metastases after 3 months after start of effective treatment. This is a sign of healing.
- Radiation induced insufficiency breaks should not be interpreted as metastases
- MRI is more sensitive and specific for finding bone metastases in the spine and pelvis. But MRI is much more resource-demanding, therefore a bone scan will often be the first choice.
Sources of error
- False negative bone scan occurs with myelomatose and in osteolytic metastases
- Apparent outbreak of bone metastases can occur in conjunction with treatment despite clinical improvement (flare phenomenon)
- Stage grouping of cancer with a tendency for bone marrow and bone metastases
- Primary bone tumor
- Unclear bone pain in patients without known cancer disease
- Sclerotic tumors for example bone metastases from prostate cancer, breast, or lung
- To diagnose primary tumors or relapse