A bone scan is an imaging test that helps doctors look for abnormalities within the bones. It uses a small amount of a radioactive substance to create detailed pictures of the skeletal system. This procedure is a common diagnostic tool in prostate cancer management, providing specific information about bone health. The scan detects areas where bone activity might be altered.
Purpose of a Bone Scan for Prostate Cancer
A bone scan determines if prostate cancer has spread beyond the prostate gland to the bones, a process known as metastasis. Prostate cancer often spreads to bones, frequently affecting areas like the pelvis and spine. Detecting this spread is important for determining the cancer’s stage, which guides treatment decisions.
This test is usually recommended for men diagnosed with higher-risk prostate cancer. This includes those with elevated prostate-specific antigen (PSA) levels, a high Gleason score (above 7), palpable tumors (clinical stage T2 or T3), or a high percentage of positive biopsy cores. It is also considered if a patient develops symptoms such as deep, aching bone pain, unexplained fractures, or neurological issues like leg weakness or numbness.
The Bone Scan Procedure
The bone scan procedure involves several steps. Patients may receive instructions beforehand, such as drinking extra water to help clear excess tracer from the body. It is also recommended to remove any jewelry or metal items that could interfere with imaging.
The process begins with an injection of a small amount of a radioactive substance, often called a “tracer,” into a vein, typically in the arm. This tracer is absorbed by the bones, and patients might feel a cool sensation during the injection. After the injection, there is a waiting period, usually two to four hours, allowing the tracer to circulate throughout the body and accumulate in the bones.
Once the waiting period is complete, the patient lies still on a scanning table while a large camera, known as a gamma camera, moves slowly over and around the body. This camera detects the gamma rays emitted by the tracer, creating images. The scan itself is painless and typically takes about 30 minutes.
Interpreting the Results
A radiologist, often specializing in nuclear medicine, reviews the images from the bone scan. They look for areas of increased tracer uptake, frequently called “hot spots.” These hot spots suggest higher metabolic activity in the bone, which can indicate cancer cells or other bone abnormalities.
While hot spots can signal prostate cancer spread to the bones, they are not exclusive to cancer. Other non-cancerous conditions, such as arthritis, recent fractures, or infections, can also cause increased tracer uptake. A “negative” or “normal” scan indicates no abnormal tracer uptake, suggesting no detectable bone metastases at that time. The bone scan results are one piece of information contributing to the broader diagnostic understanding.
Next Steps After the Scan
After the bone scan, results are typically available within two weeks, and your doctor will discuss the findings. If the scan is negative, it suggests the cancer may be confined to the prostate. In such cases, the medical team usually proceeds with treatment plans focused on localized disease.
If the scan is positive and shows “hot spots,” this indicates potential cancer spread. To confirm if these spots are cancerous, the doctor may order further imaging tests, such as an MRI or CT scan, for a more detailed look. In some instances, a bone biopsy, where a small tissue sample is taken from the suspicious area, may be performed. If bone metastasis is confirmed, the treatment approach will likely shift towards systemic therapies that treat the whole body, rather than just the prostate, to manage widespread disease.