Bone scan

Bone scan or radionuclide scan involves an injection of a small amount of a radioactive material intravenously.  The radioactive fluid is attracted to bone cells.  More active bone cells involved with inflammation or fracture take up a greater amount of radioactivity than normal cells.  These spots are darker on the scan.   A few hours after the injection, the scanning begins with you lying flat on your stomach for about 60 minutes while a scanner measures the radioactivity in the lumbar spine.  The presence of “dark” spots does not indicate a specific diagnosis because a number of different health problems result in increased activity.  Additional evaluation is usually required to establish a specific diagnosis.

Bone scan

What is a bone scan?

A bone scan (radionuclide imaging) is a technique to visualize organ activity by measuring the uptake of a small amount of radioisotope material.  The radioactivity level is in proportion to the uptake by the targeted organ.  Different isotopes are taken up by specific organs.  Bone can is not invasive or associated with significant risk.  Bone scans are an excellent technique to identify abnormalities in bone.  Decreased activity in bone results in a decrease in activity on the scan.  Increased activity, as associated with a fracture or cancer, results in a hot spot on the scan.

How is a bone scan taken?

Small amount of a radioactive isotope that attaches to bone is injected intravenously.  The patient is placed in front of a scanner that detects the areas of radioactivity.  The scans are taken up at variable times after the injection.  Some scans are taking very soon after injection while others are taken 2 to 4 hours after injection.  Occasionally, scans are taken 1 to 3 days after injection particularly in older patients to allow for a measureable effect shown by growing bone after an osteoporotic fracture.

What is a SPECT scan?

Single-photon emission computed tomography (SPECT) bone scan offers more accurate localization of lesions than associated with bone scans.  Radioactivity can be localized to specific portions of a structure such as a vertebral body versus a spinous process, or a facet joint.  Facet joint arthritis can be identified by SPECT scan.  SPECT scan can also be used to evaluate the status of spinal fusions after operative procedures.

What is a PET scan?

Positron emission tomography (PET) is a radioactive technique that identifies an increased metabolic rate in the studied organ.  Increased metabolism is seen in tumor cells before there are anatomic changes.  This technique is used more frequently to identify early stages of lung and breast cancer.  The technique is used infrequently for the evaluation of the spine.