Coincidence time resolution of 30 ps FWHM using a pair of Cherenkov-radiator-integrated MCP-PMTs
Coincidence time resolution of 30 ps FWHM using a pair of Cherenkov-radiator-integrated MCP-PMTs
复制标题
DOI：
10.1088/1361-6560/ab0fce
复制
发表时间：
2019-04-01
影响因子：
3.5
通讯作者：
Hasegawa, T.
中科院分区：
文献类型：
--
作者：
Ota, R.;Nakajima, K.;Hasegawa, T.
专门用于飞行时间正电子发射断层扫描（PET）的辐射探测器已经被开发出来，并且通过仔细优化闪烁器和光电探测器，已经实现了亚100 ps半高全宽（FWHM）的符合时间分辨率（CTR）。通过使用一对湮灭伽马射线实现30 ps FWHM的CTR将允许我们在4.5 mm的精度内直接定位湮灭点。这种直接定位可以潜在地消除临床PET系统中的图像重建过程的要求，这将对临床协议和分子成像产生巨大影响。为了获得如此高的CTR，研究人员研究了诸如切伦科夫辐射和热带内发光的瞬发发射的使用。虽然即使使用基于切伦科夫的探测器也仍然具有挑战性，以实现30 ps FWHM的CTR，但实验测量的CTR正在接近目标。在这项工作中，我们开发了一个切伦科夫辐射器集成微通道板光电倍增管（CRI-MCP-PMT），在辐射器和光电阴极之间没有光学边界，并对其定时性能进行了研究。通过去除光学边界，消除了反射并且改善了到光阴极的透射，从而导致高定时能力。结果，通过使用一对CRI-MCP-PMT获得了30.1 +/- 2.4 ps FWHM的CTR，其相当于沿着响应线（LOR）的4.5 +/- 0.3 mm沿着的位置分辨率。
Radiation detectors dedicated to time-of-flight positron emission tomography (PET) have been developed, and coincidence time resolution (CTR) of sub-100 ps full width at half maximum (FWHM) has been achieved by carefully optimizing scintillators and photodetectors. Achieving a CTR of 30 ps FWHM by using a pair of annihilation gamma-rays would allow us to directly localize the annihilation point within an accuracy of 4.5 mm. Such direct localization can potentially eliminate the requirement of image reconstruction processes in clinical PET systems, which would have a huge impact on clinical protocols and molecular imaging. To obtain such a high CTR, researchers have investigated the use of prompt emissions such as Cherenkov radiation and hot-intra band luminescence. Although it is still challenging to achieve a CTR of 30 ps FWHM even with a Cherenkov-based detector, the experimentally measured CTR is approaching the goal. In this work, we developed a Cherenkov-radiator-integrated micro-channel plate photomultiplier tube (CRI-MCP-PMT), where there are no optical boundaries between the radiator and photocathode, and its timing performance was investigated. By removing the optical boundaries, reflections are eliminated and transmission to the photocathode is improved, resulting in high timing capability. As a result, a CTR of 30.1 +/- 2.4 ps FWHM, which is equivalent to a position resolution of 4.5 +/- 0.3 mm along a line of response (LOR), was obtained by using a pair of CRI-MCP-PMTs.