A new form of tomographic imaging that is as safe and versatile as conventional tomography but gives entirely different information is causing excitement among medical physicists and a few physicians.
While conventional tomography gives anatomic images, this new technique provides a look at local metabolic and physiological functions in tissues. It is noninvasive, makes use of physiological biochemicals, can detect small metabolic changes, and has a resolving power approaching that of currently used tomographic scanners. The procedure is called positron emission transaxial tomography (PETT) and while still a research tool, it is already offering valuable insights into normal and disease processes.
The standard computed tomograph transmits x-rays through tissue, and differential absorption of these rays forms the image, giving a static look at organs of the body. With PETT, positron-emitting isotopes are incorporated into natural biochemical substances such as glucose (or its analogue, deoxyglucose [DOG]), ammonia, fatty acids, or catecholamines,