Imaging with nuclear radiology, ultrasonography, computed tomography, positron emission tomography, and magnetic resonance continues to be refined as designs of sophisticated equipment are improved and the applications of these revolutionary modalities are constantly investigated. Of current importance is the need to ascertain which of the new modalities is most useful in a given situation. Although a cogent philosophic evaluation of these advanced technologies may be needed, dramatic advances in imaging continue.
Refinements in instrumentation, together with an increasing awareness of the various clinical applications of nuclear radiology, underscore the increasing importance of single proton emission tomography. Although myocardial prefusion studies using thallium 201 chloride still remain the most frequently performed procedures with single proton emission tomography, perfusion studies of the brain are now becoming increasingly significant. It is anticipated that the Food and Drug Administration will soon release iodine 123 iodoamphetamines for routine clinical use. In addition, several technetium Tc