缺氧对软X射线照射细胞的相对生物效应和氧增强比的影响。

The Effect of Hypoxia on Relative Biological Effectiveness and Oxygen Enhancement Ratio for Cells Irradiated with Grenz Rays.

作者信息

Chan Chun-Chieh, Chen Fang-Hsin, Hsueh Kuang-Lung, Hsiao Ya-Yun

机构信息

Department of Computer Science and Information Engineering, National Formosa University, Yunlin 632301, Taiwan.

Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan 33302, Taiwan.

出版信息

Cancers (Basel). 2022 Feb 28;14(5):1262. doi: 10.3390/cancers14051262.

DOI:10.3390/cancers14051262

PMID:35267573

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8909589/

Abstract

Grenz-ray therapy (GT) is commonly used for dermatological radiotherapy and has a higher linear energy transfer, relative biological effectiveness (RBE) and oxygen enhancement ratio (OER). GT is a treatment option for lentigo maligna and lentigo maligna melanoma. This study aims to calculate the RBE for DNA double-strand break (DSB) induction and cell survival under hypoxic conditions for GT. The yield of DSBs induced by GT is calculated at the aerobic and hypoxic conditions, using a Monte Carlo damage simulation (MCDS) software. The RBE value for cell survival is calculated using the repair-misrepair-fixation (RMF) model. The RBE values for cell survival for cells irradiated by 15 kV, 10 kV and 10 kVp and titanium K-shell X-rays (4.55 kV) relative to Co γ-rays are 1.0-1.6 at the aerobic conditions and moderate hypoxia (2% O), respectively, but increase to 1.2, 1.4 and 1.9 and 2.1 in conditions of severe hypoxia (0.1% O). The OER values for DSB induction relative to Co γ-rays are about constant and ~2.4 for GT, but the OER for cell survival is 2.8-2.0 as photon energy decreases from 15 kV to 4.55 kV. The results indicate that GT results in more DSB induction and allows effective tumor control for superficial and hypoxic tumors.

摘要

接触X线疗法（GT）常用于皮肤科放射治疗，具有较高的线能量传递、相对生物效应（RBE）和氧增强比（OER）。GT是恶性雀斑和恶性雀斑样黑色素瘤的一种治疗选择。本研究旨在计算GT在缺氧条件下诱导DNA双链断裂（DSB）和细胞存活的RBE。使用蒙特卡罗损伤模拟（MCDS）软件计算GT在有氧和缺氧条件下诱导的DSB产量。使用修复-错配-固定（RMF）模型计算细胞存活的RBE值。相对于钴γ射线，15 kV、10 kV和10 kVp以及钛K壳层X射线（4.55 kV）照射的细胞在有氧条件和中度缺氧（2% O）下的细胞存活RBE值分别为1.0-1.6，但在严重缺氧（0.1% O）条件下分别增加到1.2、1.4、1.9和2.1。相对于钴γ射线，GT诱导DSB的OER值约为常数，约为2.4，但随着光子能量从15 kV降至4.55 kV，细胞存活的OER为2.8-2.0。结果表明，GT可诱导更多的DSB，并能有效控制浅表和缺氧肿瘤。