Regional brain blood-flow measurements can provide essential data for effective care and management of neurological diseases. A hindrance to routine use of these procedures has been the lack of good high-resolution single-photon tomographic imaging systems that can be purchased at reasonable cost. Using new cost-effective detector technology, this project will develop a high-resolution, highsensitivity, SPECT brain-imaging system. Each of four separate fields of view will simultaneously image the entire brain volume, producing high-resolution emission computed tomographic images of Tc-99m and I-123 labeled brain blood-flow tracers. With a new innovative scintillation detector design, the system is composed of readily available components that are essentially the same as those used in current conventional design flat gamma cameras. The system will be four times as sensitive as a single-head rotating gamma camera and can easily switch between high-resolution and highsensitivity modes of operation. The specific objective of Phase I research is to experimentally develop optimal component configurations for the new detector design and assemble a detector that will be the basis for constructing a complete imaging system in Phase II.Awardee's statement of the potential commercial applications ofthe research: This new detector design will be the basis for a very cost-effective dedicated SPECT brain-imaging system. With the advent of Tc-99m and I-123 labeled agents, routine tomographic imaging of regional brain blood flow could be used if affordable, good brain SPECT systems were available.National Institute of Neurological Disorders and Stroke (NINDS)