Shin Jin-Sol, Choi Hoon, Shin Hun Joo, Kim Shin Wook, Park Hyeong Wook, Kim Jina, Kim Aeran, Hwang Jinho, Seol Yunji, Oh Taegeon, Jang Hong Seok, Choi Byung Ock, Kang Young-Nam
Department of Biomedicine & Health Sciences, The Catholic University of Korea, 222 Banpo Road (Catholic University of Korea), Seocho-gu, Seoul, Korea.
Advanced Institute for Radiation Fusion Medical Technology, College of Medicine, The Catholic University of Korea, Annex B1 222 Banpo Road (Catholic University Seoul St. Mary's Hospital), Seocho-gu, Seoul, Korea.
Australas Phys Eng Sci Med. 2019 Sep;42(3):811-818. doi: 10.1007/s13246-019-00786-x. Epub 2019 Aug 13.
The nondestructive dosimetry achieved with electron paramagnetic resonance (EPR) dosimetry facilitates repetitive recording by the same dosimeter to increase the reliability of data. In precedent studies, solid paraffin was needed as a binder material to make the lithium formate monohydrate (LFM) EPR dosimeter stable and nonfragile; however, its use complicates dosimetry. This study proposes a newly designed pure LFM EPR dosimeter created by inserting LFM into a 3D-printed container. Dosimetric characteristics of the LFM EPR dosimeter and container, such as reproducibility, linearity, energy dependence, and angular dependence, were evaluated and verified through a radiation therapy planning system (RTPS). The LFM EPR dosimeters were irradiated using a clinical linear accelerator. The EPR spectra of the dosimeters were acquired using a Bruker EMX EPR spectrometer. Through this study, it was confirmed that there is no tendency in the EPR response of the container based on irradiation dose or radiation energy. The results show that the LFM EPR dosimeters have a highly sensitive dose response with good linearity. The energy dependence across each photon and electron energy range seems to be negligible. Based on these results, LFM powder in a 3D-printed container is a suitable option for dosimetry of radiotherapy. Furthermore, the LFM EPR dosimeter has considerable potential for in vivo dosimetry and small-field dosimetry via additional experiments, owing to its small effective volume and highly sensitive dose response compared with a conventional dosimeter.
电子顺磁共振（EPR）剂量测定法实现的无损剂量测定有助于同一剂量计进行重复记录，以提高数据的可靠性。在先前的研究中，需要使用固体石蜡作为粘合剂材料，以使一水合甲酸锂（LFM）EPR剂量计稳定且不易破碎；然而，其使用使剂量测定变得复杂。本研究提出了一种新设计的纯LFM EPR剂量计，通过将LFM插入3D打印容器中制成。通过放射治疗计划系统（RTPS）对LFM EPR剂量计和容器的剂量学特性，如再现性、线性、能量依赖性和角度依赖性进行了评估和验证。使用临床直线加速器对LFM EPR剂量计进行照射。使用布鲁克EMX EPR光谱仪获取剂量计的EPR光谱。通过这项研究，证实了基于照射剂量或辐射能量，容器的EPR响应没有趋势。结果表明，LFM EPR剂量计具有高度敏感的剂量响应和良好的线性。在每个光子和电子能量范围内的能量依赖性似乎可以忽略不计。基于这些结果，3D打印容器中的LFM粉末是放射治疗剂量测定的合适选择。此外，由于与传统剂量计相比，LFM EPR剂量计的有效体积小且剂量响应高度敏感，通过额外的实验，其在体内剂量测定和小场剂量测定方面具有相当大的潜力。
