Time-of-flight positron emission tomography using Cerenkov luminescence in bismuth germanate

使用锗酸铋中的切伦科夫发光进行飞行时间正电子发射断层扫描

基本信息

批准号：
10376047
负责人：
Sun Il Kwon
金额：
$ 36.9万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-05-01 至 2025-01-31
项目状态：
未结题

项目摘要

SUMMARY Positron emission tomography (PET) is widely used as a diagnostic molecular imaging technique and clearly has had a significant impact on human healthcare. There have been significant improvements in PET technology by employing time-of-flight (TOF) capability that measures the difference in arrival time of the two 511 keV gamma annihilation rays. This TOF information spatially constrains the origin of the event, leading to improved image quality due to the increased signal-to-noise ratio (SNR) and effective sensitivity in the PET scan. The scintillator bismuth germanate (BGO), however, has several better properties for PET applications than L(Y)SO, such as higher stopping power and higher photo-electric fraction. BGO also has no background activity and can be produced at lower cost than L(Y)SO. However, a major drawback of BGO is the poor coincidence timing resolution originating from the moderate light yield and slow decay time of scintillation photon production. Therefore, BGO has not been considered for use in current generation TOF PET scanners. Theoretically, when a 511keV gamma ray interacts in a scintillator, a small number of optical Cerenkov photons are produced promptly by energetic electrons released by photoelectric or Compton interactions. The Cerenkov photons are produced within an extremely short time frame and earlier than scintillation photons, Thus the Cerenkov photons should provide better timing information for PET. Interestingly, BGO has properties that lead to it producing more Cerenkov photons than other scintillators. Recently, we showed, for the first time, the influence of prompt Cerenkov photons on the timing properties of BGO using latest generation silicon photomultipliers (SiPMs) developed by our partner FBK. Thus, our proposed concept for BGO is that Cerenkov photons are used to obtain prompt timing information while scintillation photons provide essential energy information for PET. The major goals of this proposal are i) to improve coincidence timing resolution of BGO by detecting more Cerenkov photons for TOF PET applications, ii) to develop signal reducing methods and read-out electronics for signals generated by both Cerenkov and scintillation photons, and iii) to finally develop and evaluate the first practical BGO-based TOF PET detector modules, which have 5 × 5 cm2 cross-sectional area and a coincidence timing resolution of ≤300 ps FWHM. If successful, this proposal forms the basis for developing novel BGO-based TOF PET scanners with higher sensitivity and lower cost than current PET scanners.

概括正电子发射断层扫描 (PET) 被广泛用作诊断分子成像技术，并且清楚地表明对人类医疗保健产生了重大影响 PET 技术已取得显着进步。通过使用飞行时间 (TOF) 功能来测量两个 511 keV 的到达时间差异伽马湮灭射线。TOF 信息在空间上限制了事件的起源，从而改进了由于 PET 扫描中信噪比 (SNR) 的提高和有效灵敏度的提高，图像质量得到提高。然而，对于 PET 应用，闪烁体锗酸铋 (BGO) 具有比 L(Y)SO，例如更高的阻止能力和更高的光电分数，也没有背景活性。且其生产成本比 L(Y)SO 低。然而，BGO 的一个主要缺点是重合性较差。定时分辨率源于闪烁光子产生的中等光输出和缓慢的衰减时间。因此，BGO 尚未被考虑用于当前一代 TOF PET 扫描仪。理论上，当 511keV 伽马射线在闪烁体中相互作用时，少量光学切伦科夫光子由光电或康普顿相互作用释放的高能电子迅速产生。光子是在极短的时间内产生的，并且比闪烁光子更早，因此切伦科夫光子应该可以为 PET 提供更好的定时信息。它比其他闪烁体产生更多的切伦科夫光子。最近，我们首次展示了瞬发切伦科夫光子对计时特性的影响 BGO 使用我们的合作伙伴 FBK 开发的最新一代硅光电倍增管 (SiPM) 因此，我们提出了这一建议。 BGO的概念是切伦科夫光子用于获取即时定时信息，而闪烁光子用于获取即时定时信息为 PET 提供必要的能源信息该提案的主要目标是 i) 提高一致性。通过检测更多用于 TOF PET 应用的切伦科夫光子来提高 BGO 的定时分辨率，ii) 开发信号减少由切伦科夫和闪烁光子产生的信号的方法和读出电子设备， iii) 最终开发和评估第一个实用的基于 BGO 的 TOF PET 探测器模块，该模块具有 5 × 5 cm2 横截面积和 ≤300 ps FWHM 的重合定时分辨率如果成功，该建议。构成了开发新型基于 BGO 的 TOF PET 扫描仪的基础，该扫描仪具有更高的灵敏度和更低的成本当前的 PET 扫描仪。