高分辨率碲锌镉正电子发射断层扫描系统的模拟

A simulation of a high-resolution cadmium zinc telluride positron emission tomography system.

作者信息

Stanford-Hill Riley, Groll Andrew, Levin Craig S

机构信息

Molecular Imaging Instrumentation Laboratory and Department of Physics, Stanford University, Stanford, California, USA.

Molecular Imaging Instrumentation Laboratory and Department of Radiology, Stanford University, Stanford, California, USA.

出版信息

Med Phys. 2024 Feb;51(2):1340-1350. doi: 10.1002/mp.16856. Epub 2023 Dec 15.

DOI:10.1002/mp.16856

PMID:38100261

Abstract

BACKGROUND

A CZT (cadmium zinc telluride) PET (positron emission tomography) system is being developed at Stanford University. CZT has the promise of outperforming scintillator-based systems in energy and spatial resolution but has relatively poor coincidence timing resolution.

PURPOSE

To supplement GATE (GEANT 4 Application for Emission Tomography) simulations with charge transport and electronics modeling for a high-resolution CZT PET system.

METHODS

A conventional GATE simulation was supplemented with electron-hole transport modeling and experimentally measured single detector energy resolution to improve the system-level understanding of a CZT high-resolution PET system in development at Stanford University. The modeling used GATE hits data and applied charge transport in the crystal and RC-CR processing of the simulated signals to model the electronics, including leading-edge discriminators and peak pick-off. Depth correction was also performed on the simulation data. Experimentally acquired data were used to determine energy resolution parameters and were compared to simulation data.

RESULTS

The distributions of the coincidence timing, anode energy, and cathode energy are consistent with experimental data. Numerically, the simulation achieved 153 ns FWHM coincidence time resolution (CTR), which is of the same order of magnitude as the raw 210 ns CTR previously found experimentally. Further, the anode energy resolution was found to be 5.9% FWHM (full width at half maximum) at 511 keV in the simulation, which is between the experimental value found for a single crystal of 3% and the value found for the dual-panel setup of 8.02%, after depth correction.

CONCLUSIONS

Developing this advanced simulation improves upon the limitations of GATE for modeling semiconductor PET systems and provides a means for deeper analysis of the coincidence timing resolution and other complementary electron-hole dependent system parameters.

摘要

背景

斯坦福大学正在研发一种碲化镉锌（CZT）正电子发射断层扫描（PET）系统。CZT有望在能量和空间分辨率方面优于基于闪烁体的系统，但符合计时分辨率相对较差。

目的

通过电荷传输和电子学建模对高分辨率CZT PET系统进行补充，以完善GATE（用于发射断层扫描的GEANT 4应用程序）模拟。

方法

在传统的GATE模拟基础上，补充电子-空穴传输建模和实验测量的单探测器能量分辨率，以提高对斯坦福大学正在研发的CZT高分辨率PET系统的系统级理解。该建模使用GATE命中数据，并应用晶体中的电荷传输以及模拟信号的RC-CR处理来对电子学进行建模，包括前沿鉴别器和峰值提取。还对模拟数据进行了深度校正。使用实验获取的数据来确定能量分辨率参数，并与模拟数据进行比较。

结果

符合计时、阳极能量和阴极能量的分布与实验数据一致。在数值上，模拟实现了153 ns半高宽符合时间分辨率（CTR），与之前实验发现的原始210 ns CTR处于同一数量级。此外，在模拟中发现，在511 keV时阳极能量分辨率为5.9%半高宽（半高全宽），经过深度校正后，该值介于单晶实验值3%和双面板设置实验值8.02%之间。