Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
Phys Med Biol. 2011 Mar 21;56(6):1563-84. doi: 10.1088/0031-9155/56/6/004. Epub 2011 Feb 18.
This paper investigates the performance of 1 mm resolution cadmium zinc telluride (CZT) detectors for positron emission tomography (PET) capable of positioning the 3D coordinates of individual 511 keV photon interactions. The detectors comprise 40 mm × 40 mm × 5 mm monolithic CZT crystals that employ a novel cross-strip readout with interspersed steering electrodes to obtain high spatial and energy resolution. The study found a single anode FWHM energy resolution of 3.06 ± 0.39% at 511 keV throughout most of the detector volume. Improved resolution is expected with properly shielded front-end electronics. Measurements made using a collimated beam established the efficacy of the steering electrodes in facilitating enhanced charge collection across anodes, as well as a spatial resolution of 0.44 ± 0.07 mm in the direction orthogonal to the electrode planes. Finally, measurements based on coincidence electronic collimation yielded a point spread function with 0.78 ± 0.10 mm FWHM, demonstrating 1 mm spatial resolution capability transverse to the anodes-as expected from the 1 mm anode pitch. These findings indicate that the CZT-based detector concept has excellent performance and shows great promise for a high-resolution PET system.
本论文研究了 1 毫米分辨率的碲锌镉（CZT）探测器在正电子发射断层扫描（PET）中的性能，这种探测器能够定位单个 511keV 光子相互作用的三维坐标。探测器由 40mm×40mm×5mm 的整体式 CZT 晶体组成，采用新型的交叉条读出技术和交错的引导电极，以获得高空间和能量分辨率。研究发现，在探测器的大部分体积中，单个阳极的 FWHM 能量分辨率在 511keV 时为 3.06±0.39%。通过适当屏蔽前端电子设备，可以提高分辨率。使用准直束进行的测量证明了引导电极在促进阳极之间增强电荷收集方面的有效性，以及与电极平面正交方向上的空间分辨率为 0.44±0.07mm。最后，基于符合电子准直的测量得到了 0.78±0.10mm FWHM 的点扩散函数，表明在与阳极垂直的方向上具有 1 毫米的空间分辨率能力——这与 1 毫米的阳极间距相符。这些发现表明，基于 CZT 的探测器概念具有优异的性能，有望成为一种高分辨率 PET 系统。
