title: A pinhole gamma camera with optical depth-of-interaction elimination.
abstract: The performance of pinhole single photon emission computed tomography (SPECT) depends on the spatial resolution of the gamma-ray detectors used. Pinhole cameras suffer from strong resolution loss due to the varying depth-of-interaction (DOI) of gamma quanta that enter the detector material at an angle. We eliminate DOI effects in a scintillation gamma camera via a dedicated optic fiber bundle that acts as a focusing collimator for light generated in a scintillation crystal. A curved crystal is connected to a concavely shaped fiber-optic bundle such that the fibers connect perpendicularly to the crystal's convex surface and point straight at the pinhole opening. Limiting the fiber numerical apertures can be used to suppress resolution losses due to light spread. Here we demonstrate experimentally that this prototype position-sensitive gamma sensor successfully eliminates DOI effects, and has an intrinsic resolution of better than 280 microm full width at half maximum with an interaction probability of 67% for 140 keV photons. Therefore, the detector has great potential for increasing the resolution of pinhole SPECT.
authors.affiliation: Department of Nuclear Medicine, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands. Section of Radiation Detection and Medical Imaging, Applied Sciences, Delft University of Technology, Delft, The Netherlands.
authors.forename: Marc A N
authors.initials: MA
authors.lastname: Korevaar
authors.forename: Jan W T
authors.initials: JW
authors.lastname: Heemskerk
authors.forename: Freek J
authors.initials: FJ
authors.lastname: Beekman
mesh_terms: D016477:Artifacts; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D015902:Gamma Cameras; D007089:Image Enhancement / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation*