A bone scan (nuclear medicine bone scintigraphy) is an imaging procedure that provides functional information about the skeleton by injecting a small amount of a radioactive tracer into a vein. This tracer detects areas of abnormal bone metabolism, such as those caused by infection, injury, or disease. The total time commitment is a multi-stage process that typically spans several hours.
The Initial Phase: Injection and Waiting
The procedure begins with the intravenous injection of a radiotracer, usually a technetium-99m labeled compound, which takes only a few minutes. The tracer travels through the bloodstream and accumulates in the bones. The most significant portion of the total procedure time is the waiting period, necessary for the tracer to be properly absorbed by the skeleton.
This uptake phase typically lasts between two and four hours. The prolonged wait allows the radioactive material to bind to the bone tissue while simultaneously clearing from the soft tissues and bloodstream. If the scan were performed too early, the residual tracer in the surrounding tissues would obscure the skeletal details, making the images difficult to interpret.
During this waiting period, patients are often encouraged to drink several glasses of water to help flush the excess tracer from the body through the urinary system. Depending on the facility’s protocol, the patient may be allowed to leave the premises during this time, provided they return punctually for the imaging session. The patient must follow the hydration instructions carefully to ensure the best possible image contrast and quality.
Duration of the Imaging Session
Once the uptake phase is complete, the patient returns for imaging, which is performed using a specialized camera. Before the scan begins, the patient is usually asked to empty their bladder, which helps ensure a clearer view of the pelvic bones by removing accumulated tracer. The patient then lies on a narrow scanning table, and the camera moves slowly over the body to detect the gamma rays emitted by the tracer in the bones.
The imaging session typically ranges from 30 to 60 minutes, with the camera often performing a full-body sweep. Remaining completely still during this time is necessary to prevent blurring, which could require repeating the scan and lengthen the total time. The camera moves very close to the patient’s body, sometimes requiring the patient to be repositioned to capture specific views of areas of interest.
While the imaging is non-invasive and painless, the requirement to lie motionless for up to an hour can be challenging for some individuals. The technologist remains present to monitor the patient and the imaging process throughout the session. Once the images are acquired, the technologist reviews them to confirm they are sufficient for the radiologist’s interpretation.
Factors That Influence Total Time
The total time increases if specialized imaging protocols are required beyond the standard two-part scan. One variation is the three-phase bone scan, often requested when evaluating conditions like bone infection or stress fractures. This protocol requires immediate imaging after the injection to capture blood flow (phase one) and soft-tissue pooling (phase two), meaning the patient must remain at the facility continuously.
The delayed phase (phase three) of this scan still requires the standard two to four-hour waiting period before the final images are taken, making the entire continuous process longer than a standard scan. Another factor that extends the imaging time is the addition of Single-Photon Emission Computed Tomography (SPECT) or SPECT/CT imaging. SPECT uses the camera to rotate around the patient, creating three-dimensional images that offer better localization of tracer uptake, which can add 15 to 30 minutes to the scanning time.
In some cases, the initial images may be inconclusive, or the medical question requires further clarification, necessitating delayed or repeat imaging. This can involve the patient returning for another set of scans 24 hours after the initial injection. This two-day protocol, while not continuous, extends the overall period a patient is involved with the procedure.
Preparing for the Appointment
A patient’s overall time commitment includes preparation time, making efficiency important. Patients are advised to arrive 15 to 30 minutes before the scheduled appointment time to complete check-in procedures. Wearing comfortable clothing and avoiding garments with excessive metal, such as zippers or large buckles, is recommended, as these items can interfere with the imaging equipment and may require the patient to change into a gown.
Proper hydration is essential for a successful scan. Patients are asked to drink plenty of fluids before and throughout the waiting period to ensure the tracer clears the soft tissue effectively. While the scan itself marks the end of the patient’s physical time at the facility, there is often a waiting period for the radiologist to review the images before the patient is dismissed.