Neutron leakage calculation of Varian medical linear accelerator with 115In foil activation and CR-39 detector by Monte Carlo simulation

IF 1.8 3区工程技术 Q3 CHEMISTRY, INORGANIC & NUCLEAR

Applied Radiation and Isotopes Pub Date : 2025-06-25 DOI:10.1016/j.apradiso.2025.112015

Mohammadreza Rezaie , Neda Zareie , Mehdi Hassanpour , Mohammad Rashed Iqbal Faruque

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引用次数: 0

Abstract

High-energy medical accelerators, such as 15 MeV electron beam Varian accelerators, are widely used in Iran and worldwide for treatment and imaging. Due to photon-neutron interactions in the head of accelerators, neutrons with high energy enter the treatment room. In this article calculation of the energy spectrum of neutron leakage using the Monte Carlo N Particle X version (MCNPX) code was investigated to determine the possibility of neutron leakage in the treatment room. The neutron leakage was measured by activating a¹¹⁵In foil and tracking the neutron density in the CR-39 detector on the patient's bed in the treatment room. Finally, by placing an adult MIRD phantom on the patient's bed in the treatment room, the neutron dose distribution per unit time in sensitive organs due to leakage neutrons has been calculated. The Monte Carlo results show that the number of neutrons entering the treatment room from the accelerator head per second is 2.22E+12 (n/s). The activity of the indium foil per gram and the Track density rate of the CR-39 detector for neutron leakage of the Vital Varian accelerator at 15 MeV in the treatment room in 10 min are 116 Bq/g and 3.9E7 tracks/(cm². s), respectively. By adjusting the field size of the accelerator for liver cancer treatment to a 5 × 5 cm² field, the effective dose rate in MIRD phantom-sensitive organs by neutron leakage is reported to be 1.62 mSv/s (97.2 mSv/min). Therefore, 15 MeV electron beam Varian accelerators have neutron leakage to the treatment room. If the principles of neutron protection are not applied to them, the leaking neutrons due to the diffusion process will have a high radiation risk for patients and treatment room technicians.

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用蒙特卡罗模拟计算115In箔活化和CR-39探测器瓦里安医用直线加速器中子泄漏

高能医疗加速器，如15mev电子束瓦里安加速器，在伊朗和全世界广泛用于治疗和成像。由于加速器头部的光子-中子相互作用，高能中子进入治疗室。本文利用蒙特卡罗N粒子X版（MCNPX）代码对中子泄漏能谱进行了计算，以确定治疗室中子泄漏的可能性。通过激活a115In箔，并在治疗室病床上的CR-39探测器中跟踪中子密度来测量中子泄漏。最后，通过在治疗室病人的床上放置一个成人MIRD幻影，计算出敏感器官因泄漏中子而单位时间内的中子剂量分布。蒙特卡罗结果表明，每秒从加速器头部进入治疗室的中子数为2.22E+12 （n/s）。在治疗室中，Vital Varian加速器15 MeV中子泄漏CR-39探测器10 min内每克铟箔活度和径迹密度率分别为116 Bq/g和3.9E7径迹/(cm2)。,分别。通过将肝癌治疗加速器的场大小调整为5 × 5 cm2，中子泄漏对MIRD幻敏器官的有效剂量率为1.62 mSv/s （97.2 mSv/min）。因此，15mev电子束瓦里安加速器有中子泄漏到治疗室。如果不应用中子防护原理，扩散过程中泄漏的中子将对患者和治疗室技术人员产生很高的辐射风险。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Radiation and Isotopes 工程技术-核科学技术

CiteScore

3.00

自引率

12.50%

发文量

406

审稿时长

13.5 months

期刊介绍： Applied Radiation and Isotopes provides a high quality medium for the publication of substantial, original and scientific and technological papers on the development and peaceful application of nuclear, radiation and radionuclide techniques in chemistry, physics, biochemistry, biology, medicine, security, engineering and in the earth, planetary and environmental sciences, all including dosimetry. Nuclear techniques are defined in the broadest sense and both experimental and theoretical papers are welcome. They include the development and use of α- and β-particles, X-rays and γ-rays, neutrons and other nuclear particles and radiations from all sources, including radionuclides, synchrotron sources, cyclotrons and reactors and from the natural environment. The journal aims to publish papers with significance to an international audience, containing substantial novelty and scientific impact. The Editors reserve the rights to reject, with or without external review, papers that do not meet these criteria. Papers dealing with radiation processing, i.e., where radiation is used to bring about a biological, chemical or physical change in a material, should be directed to our sister journal Radiation Physics and Chemistry.