A bone scan is a test used to find areas of variable bone metabolism (increased or decreased). Bone metabolism is the process of bone tissue cells dying and being replaced. Bone scans are nuclear imaging tests that are used to track and diagnose various bone diseases. Bone scans are also called scintigraphy or musculoskeletal imaging. White spots in a bone scan indicate improper bone metabolism and can result from a number of conditions.
Why is it Done
Doctors order bone scans related to a number of conditions and complaints, including Paget's disease, bone cancer, cancer that has (or might have) metastasised, joint infections, joint replacements and unexplained bone pain, according to the Arizona Health Sciences Center. If white spots show up in the scan, they can be a sign of one of these conditions.
Before a bone scan, your doctor will inject you with a radioactive material (a radioactive tracer) that will circulate through your body and will be picked up by the camera. The patterns of how the radioactive material collects in your bones can indicate a number of different diseases or injuries. In a healthy person, the radioactive material will be dispersed evenly throughout the body. If there is a problem, the material will collect in the bone at the site of the problem, showing up as white spots, according to Health and Age.
What White Spots Reveal
If a bone scan comes back with white spots it means your bones are not metabolising properly. This can indicate a bone tumour, a fracture, infection, metabolic disorders or cancer that has metastasised to the bone from a tumour that started somewhere else, according to the Mayo Clinic.
While bone scans are very good at finding where bone problems lie (as indicated by the white spots), it is often not possible to determine the cause of the problems without further tests and/or a full patient medical history, according to the Mayo Clinic. A bone scan that reveals white spots will often lead a doctor to order further imaging tests including a computerised tomography scan or a magnetic resonance imaging test. The doctor might also order a biopsy of the bone to test for cancer.
Despite the alarming sounding radiation injection, bone scans are quite safe, according to doctors at the Arizona Health Sciences Center. There is very little radiation, and it is easily metabolised by your body in the days after the procedure. Even if the material does collect in the bones, indicating a problem, it will still eventually dissipate. There is, however, a risk to pregnant women, who should not undergo bone scans unless the risks of not doing so outweigh the risks to the foetus. The radioactive material can cause birth defects.