Abstract
Positron Emission Tomography (PET) is a tool for imaging and evaluation of human physiology and function. It has recently been available in more than thirty hospitals and become popular in Japan. PET utilizes positron-emitting radionuclides such as 11C, 13N, 15O, and 18F : most of them are constituent of molecules in our body. Radioactive compounds with positron emitter have been developed and used for specific purposes. Blood perfusion, oxygen consumption, and glucose utilization are routinely performed in many institutions and visually expressed by the tomographic map with absolute pixel-by-pixel value. 18F-FDG uptake correlates with glucose utilization in tissue and is widely used for evaluating malignant tumors as well as brain function and myocardial viability. In the United States, FDA and the Health Care Financing Administration (HCFA) have recently reviewed usefulness and cost-effectiveness of FDG PET for the diagnosis of lung cancer, colon cancer, esophageal cancer, malignant lymphoma, malignant melanoma, head and neck cancer, myocardial viability, and epileptic focus. They decided to request expanded Medicare reimbursement for FDG PET to include these diseases in December 2000. We provide a brief summary of FDG PET literature and clinical examples of these diseases in this article. There have been many tracers available for tumor imaging and some of them are clinically useful. Since PET utilizes radiolabeled molecules specific for disease process, development of new radiopharmaceuticals could makes it possible to use this modality for molecular imaging in the future.
