Bone scan is an investigation done for early detection of areas of abnormal bone activities (days to months earlier than X-rays). This helps detect areas of bone damage, tumors that have spread to bones and areas of bone infection.
In this test the patient is injected through his vein with a radioactive material (called tracer). This material will circulate in the whole body before concentrating in areas of abnormal bone activity (called hot spots) e.g. tumor, fissures or infection. About two to five hours after injection, the patient lies on machine (scanner) with special cameras (called gamma cameras) that will detect the radiation from the tracer, thus identifying these areas of abnormal bone activity.
Sometimes, there are areas that will absorb minimal amount of tracer due to lack of blood supply to the bone or certain tumor. These areas are called "cold" spots.
Almost half of the tracer is removed from the body through the kidneys and bladder in urine. Thus, patients should empty their bladder immediately before images are taken by the scanner. The patient is then asked to drink plenty of water to help remove the radioactive material from the body.
Uses of bone scan:
- To find the exact site of problems causing undiagnosed bone pain.
- Early detection of bone fissures and cracks not seen on regular X-rays
- Determine if tumors from remote organs (e.g. breast or prostate) have spread to bones.
- Detect areas of bone infection.
It is advisable not to make a bone scan if he patient is pregnant to prevent exposure of the baby to radiations. If the patient is lactating, she should get rid of the milk for 2 days before feeding her baby again. After 2-3 days from injection, all radioactive materials are eliminated from the body.