The evolution of radionuclide imaging

This chapter briefly describes the evolution of scintillation imaging through the early 1980s. It is difficult, if not impossible, to evaluate the practical roles of current developments with any perspective, historical or otherwise. Waves of enthusiasm come and go. A simple analysis by Cassen of the factors entering into an overall performance index of any scanning or imaging system clearly shows that appreciable advances in instrumentation depend upon more efficient utilization of available gamma photons, and that future advances will depend upon the availability of agents having a greater photon yield and a smaller potential radiation dose. Further, the needs of the referring physician and improvements in other diagnostic modalities will have an impact on the future of nuclear medicine imaging requirements. For example, the availability of 201T1 for myocardial imaging significantly increased the demand for spatial resolution of the scintillation camera. Likewise, the introduction of gated blood-pool imaging increased the requirements for count rate capabilities and spatial resolution. The need to evaluate the myocardium in the intensive care unit resulted in the development of the portable scintillation camera and computer. On the other hand, the introduction of CT for evaluating the brain had a significant impact on the value of nuclear medicine brain imaging. The impact of digital radiology and nuclear magnetic resonance can only be speculated at this point. If anything, they will probably serve as complements to nuclear medicine procedures in the diagnostic process, with nuclear medicine serving as the primary method of establishing functional information