Instrumentation trends in nuclear medicine.

Nuclear medicine instrumentation requires use of various configurations of photon detectors for the purpose of in vivo and in vitro measurements of flow and metabolism. Computed tomography has solved a previous limitation of an ambiguous volume of interest intrinsic to projection images. Selection of instruments involves first, a definition of the medical problem to be solved; then an evaluation of the following characteristics of the candidate instruments: sensitivity, spatial resolution, saturation performance, dead time, uniformity of resolution, uniformity of sensitivity, data processing capabilities, and cost. New developments include dynamic imaging in transverse section with either single photon or positron annihilation photons, and whole-body quantitative imaging of sequential changes in radiopharmaceutical concentration.