PROJECT SUMMARY/ABSTRACT: Brain Single Photon Emission Computed Tomography (SPECT) imaging has been of great importance for many clinical applications such as epilepsy, dementia, posttraumatic stress disorder, Alzheimer’s disease, Parkinson’s disease, and tumor imaging. The conventional dual-head gamma cameras (DHGCs) which have been the mainstay in nuclear imaging (specifically for cardiac screening) are not optimized for brain imaging where achieving simultaneously high resolution and high sensitivity is necessary. Depending on the collimator choice, DHGC resolution is 7-15 mm FWHM, which is not very useful to visualize fine structures of the human brain. There are several ongoing projects with the premise of improved scanner performance compared to the DHGC systems, however they are either focusing on using old detector technology and mainly improving the collimator geometry or focusing on very expensive (order of magnitude compared with the current designs) semiconductor technology which also leads to a complex system. With this application we seek to develop a portable SPECT scanner for dynamic brain imaging with ~4 mm FWHM resolution at the same sensitivity of the DHGC or 8x more sensitivity at 7 mm resolution. The backbone of the design is our enabling technology to fabricate high resolution detectors at practical cost. The proposed project will open new avenues for low dose brain SPECT imaging applications and enable longitudinal studies.