Definition and Overview

Bones are made up of tissues and cells, making them susceptible to any mutation that can eventually lead to certain types of cancers and other diseases. To determine the presence of abnormalities in the bones, a bone scan is performed. This imaging test is also performed in cases of dislocation and fractures that are due to congenital defect, trauma, and disease as well as in monitoring the progress of a specific bone treatment. The bone scan can either cover the whole body or only specific parts such as the legs and arms.

Bone scans are performed by technicians under the supervision of either a nuclear medicine specialist or radiologist. The results, on the other hand, are interpreted by the patient’s diagnosing physician.

Who Should Undergo and Expected Results

A bone scan may be recommended if:

Other tests provide inconclusive results - In cases wherein other tests are unable to detect the source of pain or when fractures appear blurry or undetected with regular X-ray, a bone scan is typically performed.

  • The patient has cancer – The test can be used to determine if cancer has already metastasized to the bone, in which case, the bone cancer becomes secondary cancer.

  • The doctor suspects bone cancer – Although bone cancer makes up less than 1% of the entire cancers in the United States, it still kills more than 1,000 people every year, and at least 2,900 are diagnosed. Like any other cancer, prompt treatment is necessary to increase the patient's chances of survival.

  • There are other problems affecting the bones – A bone scan is also performed when bones are infected, inflamed (osteomyelitis) or fractured. It is also recommended when determining the extent of certain conditions such as osteoporosis.

  • The patient has undergone trauma – Accidents, falls, and violence may result to damage to the bones like a fracture or dislocation.

  • Medications have to be monitored – If the patient has been operated on due to a fracture, the test can show if the bones are healing nicely. If the patient is provided with medications to delay or control metastases, this exam will also be useful.

A scan result is considered normal when the tracer (a radioactive material that is injected prior to the procedure) appears to be more or less evenly distributed throughout the body. Meanwhile, tumours, cancers, and other problems of the bone may show up as a hot spot where most of the tracers are likely to gather. They may also appear lighter than other areas (cold spots).

As the test cannot pinpoint the actual bone issue, more tests are typically conducted following an abnormal bone scan result.

How Does the Procedure Work?

The doctor will prep the patient at least a few days before the exam. Although there are no food or fluid restrictions, the doctor may advise cessation of certain medications or activities for a certain period leading to the procedure.

During the test, a technician injects a tracer through a vein, where it travels to various organs and tissues of the body, including the bones. The body is given enough time to absorb the material, which then emits radiation that can be captured by a camera that produces the images of the bones. Depending on the bone issue, it may take up to 4 hours from the time the injection has made before the images are taken.

Scanning, meanwhile, can take at least an hour, where the cameras are moved around the patient. The technician may advise the patient to change positions to get clearer or more precise images.

After the test, the patient will be advised to drink plenty of fluids to flush out any remaining tracers for the next 24 to 48 hours.

Possible Risks and Complications

Although the idea of injecting a radioactive material into the body may make some people feel uncomfortable and anxious, it’s a very small amount that it doesn’t cause any untoward damage to the body. In fact, other risks and complications such as allergies, anaphylaxis (a severe form of allergy), and swelling are very rare.

Nevertheless, pregnant mothers are not allowed to undergo the procedure. Breastfeeding moms, on the other hand, may be permitted, but they need to stop breastfeeding for a certain period. Those who have undergone the exam and are traveling should carry with them a proof of the test, as some scanners in airports are highly sensitive.

References:

  • Coleman RE, Holen I. Bone metastases. In: Abeloff MD, Armitage JO, Niederhuber JE, Kastan MB, McKena WG, eds. Clinical Oncology. 4th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 57
  • Newberg A. Bone scans. In: Pretorius ES, Solomon JA, eds. Radiology Secrets Plus. 3rd ed. Philadelphia, Pa: Elsevier Mosby; 2010:chap 54.
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