What is a nuclear medicine bone scan?
Posted on 31 July 2012
Meet our expert, Dr Heinz Morkel, a highly specialised nuclear medicine physician, who practices at Mediclinic Durbanville, Mediclinic George, Mediclinic Panorama and Mediclinic Vergelegen. Nuclear medicine began more than 60 years ago and is now an extremely valuable clinical modality used for the early diagnosis, treatment and evaluation of numerous diseases.
I have been told I need a nuclear medicine bone scan. How is this different to an x-ray?
• An x-ray image is taken by using a machine to send radiation through the bone and capture an image of its different densities. It is a good indication of the bone’s structural looks.
• For a nuclear medicine scan you will be injected with a radioactive tracer of a low dose of radiation (similar to the dose used in an x-ray). This radio-labelled tracer, Tc99m MDP, then travels through your bloodstream to the bone where your bone building cells will absorb it. An image is then taken using a gamma camera, which will show your blood supply to the bone, and its bone cellular function. If there is damage or injury to the bone, more of the tracer will be absorbed for repair and this will be seen as a hot spot on the image.
For certain bone-related conditions, the bone scan is more sensitive and is therefore the preferred choice of imaging. Stress fractures, for example, show up weeks before bone damage is seen on an x-ray. For other bone conditions, the x-ray is still the best option.
Can I eat before my bone scan and take medication?
Yes, you may eat and drink before the bone scan and take any medication that you may require. Generally pain medication may be taken as we would prefer you to be as comfortable as possible for the scan, which can take as long as 30 minutes.
Is there anything I have to do during the scan?
During the scan you lie still on an examination bed or stand in front of the camera for a few images.
• We make sure you’re as comfortable as possible, but it’s also important that you remain still for extended periods of time.
• During the waiting period, of at least two hours after your tracer injection, increase your fluid intake to flush out any unnecessary radioactivity.
Will I feel side effects to the injection?
No, there are no side effects to the bone-tracer injection, as it includes phosphate, a naturally occurring building block of bones, and the body recognises it.
How long will the radioactive tracer stay in my body?
The injected Tc99m tracer has a half-life of six hours. In other words, for every six hours, half of it will remain, but if you increase your fluid intake to flush out the tracer via the urinary system it speeds up the process and all of it will be gone in one day.
If you have any questions you’d like answered, please write them in the comment box or post them on our Facebook page.