1. The University of Arizona, Center for Gamma-Ray Imaging, Department of Medical Imaging, 1609 North Warren Avenue, Tucson, Arizona 85724, United States
2. U.S. Food and Drug Administration, Center for Devices and Radiological Health, Division of Imaging and Applied Mathematics, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States
3. The University of Arizona, Center for Gamma-Ray Imaging, Department of Medical Imaging, 1609 North Warren Avenue, Tucson, Arizona 85724, United StatescUniversity of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson, Arizona 8571