The abbreviation stand for: fluorodeoxyglucose (FDG)-positron emission tomography (PET).
A positron is a positive electron which is released from the isotope flourine-28, which has a very short half life of under 2 hours, and thus the radioactive isotope decays quickly, reducing radiation to the body. The isotope is attached to glucose as glucose is metabolised by the tissues and taken up more easily by malignant and inflamed tissue like sarcoidosis.
The whole body FDG – PET scan has been one of the most important advances in the investigation and treatment of sarcoidosis as it provides a “map” of the whole body with very precise definition. This shows up sarcoidosis all over the body and in the heart, and can also direct the most appropriate places to perform a biopsy, should one be required. The procedure is similar to a CT scan – lying on a flat bed and moving through a giant doughnut-shaped machine. It is important to fast (not eat) for a specified time beforehand.
Wesley Medical Imaging will advise you of the preparation protocol when you book. The scan can show up abnormalities as small as a few millimetres in diameter and can sometimes reveal other incidental findings such as colonic polyps, cancers and thyroid disease. The test is not covered by Medicare (for sarcoid) but is well worth the expense as it provides a very accurate and comprehensive “map” of where the sarcoidosis is, and how “active” it’s extent. It usually attracts an out of pocket fee of approximately $500.
Wesley Medical Imaging at the Wesley Hospital, Brisbane has performed over 600 PET scans for sarcoidosis and this would be more than anywhere in the Southern hemisphere. This experience has gained at the Wesley has been invaluable in the management of sarcoidosis and also the ability to exclude sarcoidosis where it has been suspected. Not all PET scanning machines are the same and the expertise of the radiologists and physicians like me is as important as the scanner itself. The actual test takes about 4 hours to perform and results can take up to 2 days to get back. It is important to make a follow-up appointment to review the results with Professor Allen and discuss a course of treatment should sarcoidosis be confirmed.