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>Dependence of the coincidence aperture function of narrow BGO crystals on crystal shape and light encoding schemes
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Dependence of the coincidence aperture function of narrow BGO crystals on crystal shape and light encoding schemes
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机译：Dependence of the coincidence aperture function of narrow BGO crystals on crystal shape and light encoding schemes
Although the spatial resolution in positron emission tomography is improved by reducing the crystal width, the resolution becomes increasingly non-uniform towards the edges of the field of view. This is mainly due to penetration of the gamma rays through depth of interaction within the crystal. Crystals with straight and pointed tips with and without tungsten septa are compared to determine the effects of pointed tips and septa on spatial resolution and efficiency. Monte Carlo calculations are compared with extensive experimental results obtained from 16 coincidence lines between two four-BGO crystal/dual PMT detector assemblies. The spectral efficiencies for the different combinations are compared. A modest improvement in single-to-noise ratio at the maximum resolvable frequency is demonstrated when using tungsten septa and pointed crystals. The effects of optical coding scheme used are discussed and it is shown that most coding schemes cause diminishment of spatial resolution even at the center of the field of view, resulting from Compton scattering to adjacent crystals.
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