With bone scans, metastasis can be identified in the bones before they become visible in an x-ray.
Bone scintigraphy, commonly referred to as bone scan (also skeletal scintigraphy) is a special nuclear medical method for examination that measures the traces of radioactive agent, e.g. previously administered radioactive medication accumulated inside the bone. The distribution patterns and the amount of tracers allow for indications of an increased metabolism, such is generally found with metastasic prostate cancer.
In contrast to radiological examination procedures (CT/MRT), which primarily show the changes of the bone structure, scintigraphy primarily provides information about abnormal changes in the bone metabolism. Abnormal scintigrafic findings are, however, no evidence for metastasis, since they can also occur as a result of benign bone disease or deterioration of the joints (arthritis).
Bone scintigraphy should always be performed to rule out bone metastasis in all patients with prostate specific antigen level (PSA) above 20 ng/ml, or with aggressive tumor types (Gleason score above 7).