Applied Nuclear Physics, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America. Author to whom any correspondence should be addressed.
Phys Med Biol. 2019 Sep 5;64(17):175016. doi: 10.1088/1361-6560/ab31e3.
Exploiting the moderate Cherenkov yield from 511 keV photoelectric interactions in bismuth germanate (BGO) scintillators enables one to achieve a level of coincidence time resolution (CTR) appropriate for time-of-flight positron emission tomography (TOF-PET). For this approach, owing to the low number of promptly emitted light photons, single photon time resolution (SPTR) can have a stronger influence on achievable CTR. We have previously shown readout techniques that reduce effective device capacitance of large area silicon photomultipliers (SiPMs) can yield improvements in single photon response shape that minimize the influence of electronic noise on SPTR. With these techniques, sub-100 ps FWHM SPTR can be achieved with [Formula: see text] mm FBK near-ultra-violet high density (NUV-HD) SiPMs. These sensors are also useful for detecting Cherenkov light due to relatively high photon detection efficiency for UV light. In this work, we measured CTR for BGO crystals coupled to FBK NUV-HD SiPMs with a passive bootstrapping readout circuit that effectively reduces the SiPM device capacitance. A range of CTR values between 200 [Formula: see text] 3 and 277 [Formula: see text] 7 ps FWHM were measured for 3 [Formula: see text] 3 [Formula: see text] 3 and 3 [Formula: see text] 3 [Formula: see text] 15 mm crystals, respectively. This readout technique provides a relatively simple approach to achieve state-of-the-art CTR performance using BGO crystals for TOF-PET.
利用锗酸铋(BGO)闪烁体中 511keV 光电相互作用的适度切伦科夫产额,可以实现适用于飞行时间正电子发射断层扫描(TOF-PET)的符合时间分辨率(CTR)水平。对于这种方法,由于 promptly 发射的光光子数量较少,因此单光子时间分辨率(SPTR)对可实现的 CTR 有更强的影响。我们之前已经展示了读出技术,这些技术可以降低大面积硅光电倍增管(SiPM)的有效器件电容,从而改善单光子响应形状,最大程度地减少电子噪声对 SPTR 的影响。通过这些技术,可以实现[Formula: see text]mm FBK 近紫外高密度(NUV-HD)SiPM 的小于 100ps FWHM SPTR。由于对紫外光具有相对较高的光子探测效率,这些传感器也可用于探测切伦科夫光。在这项工作中,我们测量了与 FBK NUV-HD SiPM 耦合的 BGO 晶体的 CTR,该 SiPM 采用具有有效降低 SiPM 器件电容的被动自举读出电路。对于 3 [Formula: see text] 3 [Formula: see text] 3 和 3 [Formula: see text] 3 [Formula: see text] 15mm 晶体,分别测量了 200 [Formula: see text] 3 和 277 [Formula: see text] 7 ps FWHM 范围内的 CTR 值。这种读出技术为使用 BGO 晶体实现 TOF-PET 的最先进的 CTR 性能提供了一种相对简单的方法。