(Positron Emission Tomography)

PET/CT is a procedure that can help locate abnormal cell activity at the basic metabolism level in a patient. In cancer and some other diseases like Alzheimer’s, the way cells metabolize or process food changes before the tumor mass forms. PET can detect these changes and can often identify the presence of disease earlier than tests, which look for a tumor mass. Growing cells use glucose (a type of sugar) as a main source of energy. Cancer cells grow faster than normal cells, and as a result use more glucose. FDG is a special form of glucose that emits or gives off particles called positrons within the body’s cells. The FDG is active for a short period of time, which makes it very important that the patient be on time for their scan appointment. This special glucose is injected about 1 hour before the PET/CT exam. The PET/CT scanner takes a time exposure of the body and produces a map of where the FDG was consumed in the body. The PET/CT unit is a combined PET and a CT scanner. This allows both exams to be completed consecutively without having to reposition the patient.  The radiologist interprets the map looking for areas that demonstrate higher usage of FDG helping to determine the presence of cancer or the amount of involvement in Alzheimer’s disease, noted by less FDG used. PET/CT scans are also able to demonstrate the effectiveness of therapy in some forms of cancer. For this reason, physicians will order repeat PET scans after therapy is initiated.