Wedge-shaped scintillation crystals for positron emission tomography.
The use of wedge-shaped scintillation crystals for positron emission tomography is reevaluated with the aim of delimiting its range of benefit. A linear attenuation simulation model is used to generate the detector geometric aperture functions, and the investigation is carried out in terms of a newly introduced shape-independent definition of the spatial resolution, the "spectral resolution." Contrary to previous expectations, it is concluded that shaped crystals do not improve the performance of high resolution detection systems, either with or without intercrystal septa. However, wedges are found to be useful for lower resolution systems and the boundaries of applicability are estimated for NaI, BaF2, GSO, and BGO scintillators.
D003460:Crystallization; D013679:Technology, Radiologic; D014055:Tomography, Emission-Computed