Used or proposed in dedicated breast PET scanners. Small-animal PET scanners and also is that In this paper, we report on the effect of surface treatment and reflectors for lutetium oxyorthosilicate (LSO) arrays with aĬrystal size of 1.5 mm, which is typical of the crystal size currently used in commercial ![]() The effects of crystal surface on flood histogram quality and energy resolution were not studied with the exception of, 22 where energy resolution was studied for a 3 × 2 × 100 mm 3 crystal These studies were conducted with single crystals and tried to increase the crystal surface roughness to obtain good DOI In the past, several studies have examined the effects ofĭOI resolution for dual-ended readout detectors. Intercrystal reflector, and crystal size. Light and therefore a degradation in the quality of the flood histogram and energy resolution. Obtain good DOI resolution, which implies a significant and depth-dependent loss of scintillation Resolution since a strong gradient in light collection efficiency with depth (GLCED) is required to Dual-ended readout of a scintillation crystals or arrays is one popularĭepth-encoding method which measures DOI by using the energy ratio of the two photodetector signals and can achieve veryįor dual-ended readout depth-encoding detectors, the proper compromise needs to be found between ![]() PET scanners, 13 dedicated breast 14 and brain scanners 15 have also been developed using some form ofĭepth-encoding detector. Many approaches have been proposed and studied in the past 25 years to measure DOI. Therefore, depth-encoding detectors are required to achieve good spatial resolution, good spatial resolution uniformity, and high sensitivity simultaneously for (typically ∼10 mm, while 20–30 mm long crystals are used for clinical PET scanners) to reduce DOIĮrror at the cost of a reduction in the scanner sensitivity. Small-animal PET scanners use short crystals Small-animal and dedicated breast and brain PET scanners that use smallerĬrystal elements and smaller ring diameters as compared to whole-body clinical PET scanners. DOI errors are a more significant concern for Length increases and the scanner ring diameter decreases. The error caused by the DOI effect increases as the crystal ![]() The axial spatial resolution also degrades if events Radial offset increases due to the depth of interaction (DOI) effect. Resolution of a PET scanner degrades as the Tomography (PET) scanners typically use longĪnd narrow crystals to achieve a reasonable balance between spatial resolution and sensitivity. That improved the linearity of DOI ratio vs depth and simplifies the DOI calibration procedure also In that it provides more uniform photopeak amplitude at different depths for arrays with high GLCED,Īnd is beneficial in event selection by allowing a fixed energy window independent of depth. The geometric mean energies were also calculated for theseĭual-ended readout detectors as an alternative to the conventional summed total energy. DOI resolution improved as the gradient in light collectionĮfficiency with depth (GLCED) increased. All arrays except the polished ESR array provided good DOI resolution The two arrays using ESR reflector provided the best energy resolution and the array usingĬrystal Wrap reflector yielded the worst energy resolution. The four arrays using enhanced specular reflector (ESR) and Toray reflector provided similar quality flood histograms and the array usingĬrystal Wrap reflector gave the worst flood histogram.
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