Development of integrated prompt gamma imaging and positron emission tomography system for in vivo 3-D dose verification: a Monte Carlo study
Development of integrated prompt gamma imaging and positron emission tomography system for in vivo 3-D dose verification: a Monte Carlo study
复制标题
开发用于体内 3D 剂量验证的集成瞬发伽马成像和正电子发射断层扫描系统：蒙特卡罗研究
DOI：
10.1088/1361-6560/ab857c
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发表时间：
2020
影响因子：
3.5
通讯作者：
C. Min
中科院分区：
文献类型：
--
作者：
H. Choi;J. Jang;W. Shin;Hyojun Park;S. Incerti;C. Min
准确了解体内质子剂量分布是充分利用质子治疗潜在优势的关键。有两种具有代表性的间接活体射程验证方法，即瞬发伽马(PG)成像和正电子发射断层扫描(PET)。本研究提出了一种结合了这两种方法的优点的PG-PET系统，并提出了针对PG-PET系统优化的探测器几何形状和背景降低技术。用Geant4.10.00软件分析了水模与150 MeV质子束相互作用产生的二次辐射特性，得到了不同探测器几何形状下的二维PG分布。此外，还提出了能量窗(EW)、交互深度(DOI)和飞行时间(TOF)技术作为背景抑制技术。为了评价PG-PET系统的性能，用16个优化探测器验证了能量为80 MeV和100 MeV的两束质子在水模中产生的三维剂量分布。通过优化研究，确定了螺距为8 mm、宽度为7 mm的平行孔钨准直器的厚度为200 mm，GAGG闪烁体的厚度为30 mm。当分别采用DOI、DOI和TOF技术进行数据处理时，分别获得了3-7 MeV和2-7 MeV的最佳电子战，与仅使用3-5 MeV电子战相比，探测器的性能分别提高了约38%和167%。在这项研究中，我们证实了将二维平行孔准直器和PET探测器模块简单地结合起来，就可以得到PG分布。在未来，我们将开发一种基于不同质子能量的剂量、PG和PET分布的图像集的深度学习算法来开发一种准确的三维剂量评估技术。
An accurate knowledge of in vivo proton dose distribution is key to fully utilizing the potential advantages of proton therapy. Two representative indirect methods for in vivo range verification, namely, prompt gamma (PG) imaging and positron emission tomography (PET), are available. This study proposes a PG-PET system that combines the advantages of these two methods and presents detector geometry and background reduction techniques optimized for the PG-PET system. The characteristics of the secondary radiations emitted by a water phantom by interaction with a 150 MeV proton beam were analysed using Geant4.10.00, and the 2-D PG distributions were obtained and assessed for different detector geometries. In addition, the energy window (EW), depth-of-interaction (DOI), and time-of-flight (TOF) techniques are proposed as the background reduction techniques. To evaluate the performance of the PG-PET system, the 3-D dose distribution in the water phantom caused by two proton beams of energies 80 MeV and 100 MeV was verified using 16 optimal detectors. The thickness of the parallel-hole tungsten collimator of pitch 8 mm and width 7 mm was determined as 200 mm, and that of the GAGG scintillator was determined as 30 mm, by an optimization study. Further, 3–7 MeV and 2–7 MeV were obtained as the optimal EWs when the DOI and both the DOI and TOF techniques were applied for data processing, respectively; the detector performances were improved by about 38% and 167%, respectively, compared with that when applying only the 3–5 MeV EW. In this study, we confirmed that the PG distribution can be obtained by simply combining the 2-D parallel hole collimator and the PET detector module. In the future, we will develop an accurate 3-D dose evaluation technique using deep learning algorithms based on the image sets of dose, PG, and PET distributions for various proton energies.