Effect of lung inhomogeneity on dose distribution during radiotherapy of patient with lung cancer

Q4 Health Professions

Iranian Journal of Radiation Research Pub Date : 2020-07-10 DOI:10.18869/ACADPUB.IJRR.18.3.579

M. Zabihzadeh, Z. Ghahremani, S. Hoseini, H. Shahbazian, M. H. Ghahfarokhi

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引用次数: 0

Abstract

Background: Presence of inhomogeneities such as lung tissue with low density can perturbs the dose distribution in the path of therapeutic photon beam and causes undesired cold or hot spots. The aim of this study was to investigate the effect of lung tissue inhomogeneities on dose distribution in thorax irradiation. Materials and Methods: The Monte Carlo simulation (MC) code of EGSnrc-based BEAMnrc was used to calculate dose distribution for 6 MVSiemens Primus linear accelerator (Linac) in a homogenous phantom. Dose perturbation and inhomogeneity corrected factors (ICFs) were calculated due to implementation of lung tissue depended to the lung density and field size. Results: The maximum increased dose in lung tissue with lung density of 0.5 and 0.25gr/cm was 15.9%, 16.2%, 15.6%, 23.8 %, 24.8% and 25.0% for 6 × 6, 10 × 10 and 20 × 20 cm field sizes, respectively. The maximum ICF for these field sizes was 1.16 and 1.25 for lung density of 0.5 and 0.25gr/cm, respectively. The maximum dose reduction in lung tissue with density of 0.25 and 0.5gr/cm was 19.5% and 4.2 %, and the related ICF was estimated 0.84 and 0.95, respectively. Conclusion: Involvement of lung tissue in the path of irradiation perturbs the dose distribution which is dependent to the lung density and field size. The ICFs resulted from our MC model could be useful to accurately calculate the dose distribution in radiotherapy of lung abnormalities.

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肺不均匀性对癌症放疗剂量分布的影响

背景：不均匀性的存在，如低密度的肺组织，会干扰治疗光子束路径中的剂量分布，并导致不希望的冷点或热点。本研究的目的是研究胸部照射中肺组织不均匀性对剂量分布的影响。材料和方法：使用基于EGSnrc的BEAMnrc的蒙特卡罗模拟（MC）程序计算了6MV西门子Primus线性加速器（Linac）在均质体模中的剂量分布。由于肺组织的实施取决于肺密度和场大小，因此计算了剂量扰动和不均匀性校正因子（ICFs）。结果：在肺密度为0.5和0.25gr/cm的肺组织中，6×6、10×10和20×20cm视野的最大增加剂量分别为15.9%、16.2%、15.6%、23.8%、24.8%和25.0%。当肺密度为0.5和0.25gr/cm时，这些场大小的最大ICF分别为1.16和1.25。在密度为0.25和0.5gr/cm的肺组织中，最大剂量减少分别为19.5%和4.2%，相关ICF估计分别为0.84和0.95。结论：肺组织参与照射路径会干扰剂量分布，剂量分布与肺密度和视野大小有关。我们的MC模型产生的ICFs可用于准确计算肺部异常放射治疗中的剂量分布。

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

Iranian Journal of Radiation Research RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING-

CiteScore

0.67

自引率

0.00%

发文量

审稿时长

>12 weeks

期刊介绍： Iranian Journal of Radiation Research (IJRR) publishes original scientific research and clinical investigations related to radiation oncology, radiation biology, and Medical and health physics. The clinical studies submitted for publication include experimental studies of combined modality treatment, especially chemoradiotherapy approaches, and relevant innovations in hyperthermia, brachytherapy, high LET irradiation, nuclear medicine, dosimetry, tumor imaging, radiation treatment planning, radiosensitizers, and radioprotectors. All manuscripts must pass stringent peer-review and only papers that are rated of high scientific quality are accepted.