Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea.
Department of Radiation Oncology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea.
Med Phys. 2020 Feb;47(2):703-712. doi: 10.1002/mp.13922. Epub 2019 Dec 2.
The purpose of this study was to describe a plastic scintillating plate-based gantry-attachable dosimetry system for pencil beam scanning proton therapy to monitor entrance proton beam fluence, and to evaluate the dosimetric characteristics of this system and its feasibility for clinical use.
The dosimetry system, consisting of a plastic scintillating plate and a CMOS camera, was attached to a dedicated scanning nozzle and scintillation during proton beam irradiation was recorded. Dose distribution was calculated from the accumulated recorded frames. The dosimetric characteristics (energy dependency, dose linearity, dose rate dependency, and reproducibility) of the gantry-attachable dosimetry system for use with therapeutic proton beams were measured, and the feasibility of this system during clinical use was evaluated by determining selected quality assurance items at our institution.
The scintillating plate shortened the range of the proton beam by the water-equivalent thickness of the plate and broadened the spatial profile of the single proton spot by 11% at 70 MeV. The developed system functioned independently of the beam energy (<1.3%) and showed dose linearity, and also functioned independently of the dose rate. The feasibility of the system for clinical use was evaluated by comparing the measured quality assurance dose distribution to that of the treatment planning system. The gamma passing rate with a criterion of 3%/3 mm was 97.58%.
This study evaluated the dosimetric characteristics of a plastic scintillating plate-based dosimetry system for use with scanning proton beams. The ability to account for the interference of the dosimetry system on the therapeutic beam enabled offline monitoring of the entrance beam fluence of the pencil beam scanning proton therapy independent of the treatment system with high resolution and in a cost-effective manner.
本研究旨在描述一种用于笔形束扫描质子治疗的基于塑料闪烁板的龙门附加剂量测量系统，以监测入射质子束通量，并评估该系统的剂量学特性及其在临床应用中的可行性。
该剂量测量系统由塑料闪烁板和 CMOS 相机组成，安装在专用扫描喷嘴上，在质子束照射时记录闪烁。从累积的记录帧中计算剂量分布。测量了用于治疗质子束的龙门附加剂量测量系统的剂量学特性（能量依赖性、剂量线性、剂量率依赖性和再现性），并通过在我们机构确定选定的质量保证项目来评估该系统在临床应用中的可行性。
闪烁板将质子束的射程缩短到与板的水当量厚度相等，并将 70 MeV 时单个质子点的空间分布展宽了 11%。开发的系统独立于束能（<1.3%）运行，表现出剂量线性，并且还独立于剂量率运行。通过将测量的质量保证剂量分布与治疗计划系统的剂量分布进行比较，评估了系统用于临床的可行性。使用 3%/3mm 标准的伽马通过率为 97.58%。
本研究评估了用于扫描质子束的基于塑料闪烁板的剂量测量系统的剂量学特性。该系统能够考虑剂量测量系统对治疗束的干扰，以高分辨率和具有成本效益的方式独立于治疗系统在线监测笔形束扫描质子治疗的入射束通量。
