A bone scan is an imaging test that a doctor will perform to check for abnormalities and diagnose various medical conditions, such as a bone disease, an infection, or cancer. Doctors will interpret the bone scan results and discuss them with you, but you may also wish to see the results for yourself. The results of a bone scan imaging test are typically available about two days following the procedure. After evaluating the results, the patient may need to undergo other diagnostic tests to verify the findings.
In order to interpret the bone scan results, it is helpful to understand how the imaging test works. The doctor will inject a radioactive material into the patient's veins. As this material breaks down, it emits radiation, which can be detected by special camera equipment. The radioactive tracing material should move around the body and distribute evenly throughout the bones. Doctors will interpret the bone scan results based on whether the radioactive material distributes evenly or if it collects in a particular area.
A normal test result is seen when the radioactive tracer material does not accumulate heavily in one or more areas, but is evenly distributed. Abnormal results occur when “hot spots” can be seen. Hot spots are areas of the bone that have collected an excessive amount of the radioactive tracer. These spots may indicate a problem, such as a bone infection, cancer, or simply a bone fracture that has not yet fully healed.
Sometimes, the radioactive tracer material fails to distribute to certain areas. These are called “cold spots.” The lack of radioactive tracer in these areas may also indicate a problem, such as a type of cancer. It may also indicate that the area of bone is not receiving an adequate supply of blood, which is called a bone infarction.
Bone scan results are helpful for finding areas of potential problems; however, they cannot by themselves establish a diagnosis. The doctor may find a hot spot or a cold spot, but the results will not necessarily tell him what the cause is. After the bone scan results are evaluated, the patient may need to undergo additional tests. These tests may include a biopsy of bone tissue or other imaging tests, such as x-rays or a magnetic resonance imaging (MRI) test. The doctor will also consider the patient's medical history when establishing a likely diagnosis.
Patients should also keep in mind that some factors can interfere with the bone scan results. For instance, having a full bladder during the test can block the camera's scan of the pelvic bones. Patients who do not remain completely still during the scan may also have inconclusive results.