The following types of cancer are routinely investigated:
Cancer studies have several objectives, all designed to provide the best and most effective treatment for the disease. FDG PET is a very sensitive and specific test (90% accuracy) for detecting a tumor anywhere in the body. This allows the oncologist to more effectively target these tumors for therapy. These tests may also be used to exclude cancer if the scans appear normal.
The uses of FDG PET scans are: to detect tumors throughout the body to stage the disease from the size, malignancy and distribution of tumors inthe body. Thus the most appropriate treatment course may then be followed. to monitor the response of the cancer to treatment. FDG uptake in the body is a measure of metabolism in the body. Thus a whole body FDG PET scan can detect tumor response to therapy within two weeks of being started. This is true of chemotherapy, radiotherapy, gene therapy, immunotherapy, phototherapy, surgery or any other treatment. In this way therapies can be switched or optimized besed on this response.
Intravenous injection of 6-10 mCi of 18F-FDG is followed by a 60-90 minute uptake period before scanning. The patient is moved through the camera in 6 cm steps to cover as much of the body as necessary. Both emission scans (to measure activity in the body) and transmission scans (to measure attenuation in the body) are performed. Ten axial positions cover the 60 cm of the torso and take 50 minutes. The camera is silent.
Two types of study are performed: 18F-FDG to measure metabolism in heart muscle, and 13N-amminia to measure blood flow in the muscle. When combined, the FDG-ammonia scans (performed in the same session) may be used to determine viability of a myocardial defect area, Where the defect is present in both the flow and metabolic image the tissue is necrotic. Where there is FDG uptake despite a flow defect, tissue is stunned and re-perfusable.
A rest - (persantine) stress ammonia study is used to measure coronary artery flow reserve and/or to get a measure of both the distribution (and therefore territory of an artery) of a defect and the effect of exercise or stress through that stenosis.
The FDG metabolic study may also be combined with myocardial flow measurements from another modality.
Brain scans may be performed for a number of conditions. Some of which are listed below. Generally FDG is used to measure the distribution of brain metabolism.
conditions: trauma including closed head injury seizures effects of stroke dementias depression brain tumors (detection and response to therapy)
The increased metabolic activity at an infection/inflammation site is used to image its distribution and extent via FDG PET imaging. This can be done for prosthetic limb problems, acute infections, inflammatory response to treatments, etc.
