New imaging modalities: positron emission tomography and nuclear magnetic resonance.

Positron emission tomography and nuclear magnetic resonance represent two new imaging modalities that utilize computer technology to provide tomographic images of the body. Positron emission tomography uses special metabolic imaging agents, which are positron emitters, to provide information on the metabolic processes that take place within the liver, kidney, and brain, and to allow study of physiologic changing systems such as blood flow. Nuclear magnetic resonance is used to evaluate the chemical constituents and the chemical composition of select tomographic areas within organs of interest. Both methods show great promise for the diagnosis and management of disease.