Pixelated Scintillators for High Spatial Resolution and High Quantum Efficiency X-RayDetectors

PROJECT SUMMARY ABSTRACT The performance of many x ray imaging systems is limited by the lack of x ray detectors with simultaneous high quantum efficiency and high spatial resolutionAs examplesdigital mammography scanners typically have a resolution ofm for high quantum efficiencywhich is not sufficient to effectively detect small but critical microcalcificationsX ray micro CT scanners either use high quantum efficiencylow spatial resolution detectors together with high geometric magnification or use high spatial resolutionlow quantum efficiency detectors with thin scintillatorswhich significantly limits the scan throughputThe low resolutiontypicallymof commercial large area x ray flat panel detectors made single shot x ray phase contrast imaging system not appropriate for most applications since the resolution is determined by the fringe period and has to be at least a few pixelsResearch in pixelated scintillators during the last two decades have demonstrated pixel size determined spatial resolutionHoweverthe light guidingoutputefficiency is very lowtypically andltwhich limits the practical application of such detectors in low dose medical x ray diagnosisThe proposed research in this SBIR Phase I project will focus on developing high light guiding efficiency pixelated scintillators with specially designed and engineered sidewall surface reflectors of the pixelsThe spatial resolution defined by the pixel sizedown tomand the light guiding efficiency comparable to commercial phosphor screens of the same thickness are to be demonstratedGeneral Optics proposes to bring such high efficiency pixelated scintillators to the market through Phase I researchThe specific aims aredevelop processes to fabricatem andm pitchup tom depth silicon pixel wells withm wall thicknessand engineer the sidewall surface for high reflectivityfill the wells with scintillator materials of CsITland Gd O S TbTest the performance of the fabricated pixelated scintillators and compare them with commercial phosphor screensIntegration of the pixelated scintillators to large area CMOS cameras for fully integratedlarge area x ray detectors would be the next stage of this SBIR Phase I project PROJECT NARRATIVE Developments of x ray detectors with high quantum efficiency and high spatial resolution simultaneously will have immediate impact on numerously x ray imaging systemssuch as digital mammography and dental imaging to improve diagnosis sensitivityspecificity and precisionPixelated scintillators developed during the last two decades achieved high spatial resolution defined by the pixel size but with very low light output efficiencyThe goal of this project is to advance high spatial resolution pixelated scintillators toward practical medical diagnosis and biomedical imaging applications by boosting the quantum efficiency to comparable to commercial high quantum efficiency low resolution scintillator screens through addressing the challenge in guiding the secondaryvisible photons out of the scintillator pixels