The second task NMS-873 to elucidate the dependency of PVR on photodetector SNR and multiple interactions, with both Anger-logic and light sharing considered. As predicted by formulae (2) and (3), a higher SNR consistently results in a higher PVR (i.e., smaller positioning uncertainty), for both the scenario without multiple interactions (Fig. 11(a)) and the scenario with multiple interactions (Fig. 11(b)). For instance, for the case of 4 mm crystal without multiple interactions, the PVR is 12.4 (SNR=40) and 1.056 (SNR=5), respectively. For the case of 1 mm crystal without multiple interactions, the PVR is photosynthesis 36.8 (SNR=40) and 1.08 (SNR=5), respectively. Such a high PVR was indeed observed for a PET block detector using a one-to-one coupling scheme in our previous work . No significant difference is found among the five crystal arrays as SNR reaches below 15.
Fig. 11. The dependency of PVR on photodetector?s SNR without multiple interactions (a) and with multiple interactions (b), using the same method as shown in Fig. 9. All qualified types of interactions of 511 keV gamma rays were included.Figure optionsDownload full-size imageDownload high-quality image (371 K)Download as PowerPoint slide