School of Chemistry and Physics, the University of Adelaide, SA 5000, Australia.
Radiat Res. 2011 Oct;176(4):508-20. doi: 10.1667/rr2606.1. Epub 2011 Jul 14.
Determination and understanding of out-of-field neutron and photon doses in accelerator-based radiotherapy is an important issue since linear accelerators operating at high energies (>10 MV) produce secondary radiations that irradiate parts of the patient's anatomy distal to the target region, potentially resulting in detrimental health effects. This paper provides a compilation of data (technical and clinical) reported in the literature on the measurement and Monte Carlo simulations of peripheral neutron and photon doses produced from high-energy medical linear accelerators and the reported risk and/or incidence of second primary cancer of tissues distal to the target volume. Information in the tables facilitates easier identification of (1) the various methods and measurement techniques used to determine the out-of-field neutron and photon radiations, (2) reported linac-dependent out-of-field doses, and (3) the risk/incidence of second cancers after radiotherapy due to classic and modern treatment methods. Regardless of the measurement technique and type of accelerator, the neutron dose equivalent per unit photon dose ranges from as low as 0.1 mSv/Gy to as high as 20.4 mSv/Gy. This radiation dose potentially contributes to the induction of second primary cancer in normal tissues outside the treated area.
确定和了解基于加速器的放射治疗中的场外中子和光子剂量是一个重要的问题，因为在高能（> 10 MV）下运行的线性加速器会产生次级辐射，这些辐射会照射到靶区以外的患者解剖结构的部分区域，可能导致有害的健康影响。本文提供了文献中报道的关于高能医用线性加速器产生的外周中子和光子剂量的测量和蒙特卡罗模拟的技术和临床数据的汇编，以及报告的靶体积以外的组织的第二原发癌的风险和/或发生率。表格中的信息有助于更轻松地识别：（1）用于确定场外中子和光子辐射的各种方法和测量技术，（2）报告的与直线加速器相关的场外剂量，以及（3）由于经典和现代治疗方法，放射治疗后第二癌症的风险/发生率。无论测量技术和加速器类型如何，单位光子剂量的中子剂量当量范围从低至 0.1 mSv/Gy 到高至 20.4 mSv/Gy。这种辐射剂量可能导致治疗区域外的正常组织中发生第二原发癌。
