Bone scans work by indicating a change in the metabolic activity of the skeleton. This may be focal or global increase in uptake or be focal reduction in uptake due to destruction of the bony tissues.

The main indications for scanning are:

  • Pain. Especially after trauma, where the scan can distinguish early fractures or bony injuries from soft-tissue injury. Pain may also be an early sign of bone or joint infection, especially in children. This is often apparent before the radiological changes occur. 
  • Cancer. Where there may be silent spread of cancer to bone which has significant consequences for survival in breast, prostate and lung malignancies. It is also useful in monitoring the response of bone metastases to chemotherapy / radiotherapy. Spontaneous pain or unexpected fracture in a bone may be the first indication of either a primary or secondary cancer of bone. 

  • Low back pain. Bone scanning can indicate the site of pain which may be due to vertebral / pelvic fracture in osteoporosis or facet joint/ intervertebral disc disease. It can also diagnose injuries to the sacroiliac joint that mimic disc disease and are probably more common than disc disease. This is a specialty of CNI Molecular imaging and is generally unavailable elsewhere. 

  • Arthritis. Bone scanning is very sensitive in diagnosing early forms of arthritis before significant destruction of the joints occur. This is often evident before there are major clinical signs of joint swelling. It is particularly good at diagnosis inflammation of the sacroiliac joint at an early stage. 

  • Joint replacements. Bone scanning is often an early investigation for pain following joint replacement surgery and can indicate fractures around the joint, loosening or infection. 

  • Metabolic bone disease. This is now quite rare as most diseases are diagnosed earlier by sensitive blood tests. These diseases include Paget’s disease of bone, renal bone disease and overactivity of the parathyroid glands affecting bone. 

Preparation for a bone scan

There is generally no preparation for a bone scan other than to be well hydrated. You should inform the staff if you have recently had an intravenous injection of treatment for osteoporosis, as this can interfere with the bone scan.

Please tell staff if you think that there is any possibility of pregnancy.

Tell staff at CNI if you are breastfeeding. The radioactive tracer used in this test can get into your breast milk. Do not breastfeed your baby for 24 hours after this test. During this time, you can give your baby breast milk you stored before the test, or you can give formula. Discard the breast milk you pump for 24 hours after the test.

Please bring any recent x-rays, CT or MRI films as these are important and helpful in producing a diagnostic report for your condition.

The bone scanning procedure

A history will first be taken from you about the problem that you have been referred for, as this allows us to plan your study.

You will be injected with a small tracer dose of Technetium 99m bound to a phosphate compound (similar to what your bones are made of) into a vein, generally in your arms but occasionally in your feet. This is similar to having your blood take for pathology and very rarely causes any allergic response.

You will then be placed under the gamma camera and a “blood pool” image of the region of interest will be obtained, which indicates if there is significant inflammation or increased blood flow to the area. This is done in the first 5 minutes after the injection.

You will be asked to return for the “delayed” phase of the study approximately 2 hours later. This give the tracer a chance to be taken up and for background activity to clear from the body, usually through the kidneys. It will help if you drink plenty of fluids during this period.

On your return, we will obtain images in 2 dimensions (planar images) followed by the camera going around you in 360 degrees. A CT study will be obtained while you are in the same position (SPECT/ CT) if indicated.

Precautions after the scan

You will be radioactive for 24 hours after the procedure. It is advised that you limit time spent in close proximity to pregnant women and children.

If you are breastfeeding, do not breastfeed your baby for 24 hours after this test. During this time, you can give your baby breast milk you stored before the test, or you can give formula. Discard the breast milk you pump for 24 hours after the test.

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