PET (Positron Emission Tomography) Scan (definition of)

PET stands for "Positron Emission Tomography." This is a type of imaging process using a specialized camera along with a radioactive tracer injected into the patient, allowing pathologists to look at organs and tissues in the body. The PET scan is quite useful in the diagnosis of cancer including malignant mesothelioma; it can locate malignancies in the breast, brain, lung, colon, or prostate, help oncologists determine how advanced it is and whether it has metastasized. PET scan images are less detailed than those produced by computed tomography (CAT or CT scans) or magnetic resonance imaging (MRI); however, when cancer is in its earliest stages, it may show malignancy more clearly.

The radioactive tracer in this case is made with glucose. When this is injected into the patient, it gives off positively charged particles (positrons) which the scanner is able to use in the creation of highly detailed computerized images of internal areas where the glucose is being used. This works due to the fact that cancer cells tend to consume more glucose than normal cells, making it relatively easy to identify where malignant cells are located.

The radioactivity in the glucose has a very short half-life and is therefore not a danger to the patient. However, pregnant women must avoid this procedure. Once the tracer has been injected, the patient lies on a scanner bed inside a large, semi-enclosed mechanism and must lie still during the procedure.