Spot Scanning and Passive Scattering Proton Therapy: Relative Biological Effectiveness and Oxygen Enhancement Ratio in Cultured Cells
Spot Scanning and Passive Scattering Proton Therapy: Relative Biological Effectiveness and Oxygen Enhancement Ratio in Cultured Cells
复制标题
DOI：
10.1016/j.ijrobp.2016.01.017
复制
发表时间：
2016-05-01
影响因子：
7
通讯作者：
Shibamoto, Yuta
中科院分区：
文献类型：
--
作者：
Iwata, Hiromitsu;Ogino, Hiroyuki;Shibamoto, Yuta
目的：确定与临床使用的光子相比，点扫描质子束、被动散射质子束或两者在培养细胞中的相对生物学有效性（RBE）、氧增强比（OER）和间接效应的贡献。被动散射质子束在扩展布拉格峰（SOBP）中心的RBE由剂量-以6-MV X射线为对照，观察4种细胞系的存活曲线。然后比较点扫描和被动散射质子照射后2种细胞系的存活率。还研究了SOBP远端区域的生物学效应。本文研究了被动散射质子束和6MX X射线在两种细胞株上的OER。在10%细胞存活水平下估计RBE和OER值。测定了二甲基亚砜对辐射效应的最大保护程度，以估计对DNA损伤的间接效应的贡献。结果：被动散射质子束对4种细胞的RBE值为1.01~1.22（平均1.14），与点扫描质子束的RBE值基本一致。SOBP远端的生物效应增加。在所检测的两种细胞系中，X射线和质子的OER分别为2.74（95%可信区间，2.56 - 2.80）和3.08（2.84 - 3.11），分别为2.39（2.38 - 2.43）和2.72（2.69 - 2.75）（P
Purpose: To determine the relative biological effectiveness (RBE), oxygen enhancement ratio (OER), and contribution of the indirect effect of spot scanning proton beams, passive scattering proton beams, or both in cultured cells in comparison with clinically used photons.Methods and Materials: The RBE of passive scattering proton beams at the center of the spread-out Bragg peak (SOBP) was determined from dose-survival curves in 4 cell lines using 6-MV X rays as controls. Survival of 2 cell lines after spot scanning and passive scattering proton irradiation was then compared. Biological effects at the distal end region of the SOBP were also investigated. The OER of passive scattering proton beams and 6 MX X rays were investigated in 2 cell lines. The RBE and OER values were estimated at a 10% cell survival level. The maximum degree of protection of radiation effects by dimethyl sulfoxide was determined to estimate the contribution of the indirect effect against DNA damage. All experiments comparing protons and X rays were made under the same biological conditions.Results: The RBE values of passive scattering proton beams in the 4 cell lines examined were 1.01 to 1.22 (average, 1.14) and were almost identical to those of spot scanning beams. Biological effects increased at the distal end of the SOBP. In the 2 cell lines examined, the OER was 2.74 (95% confidence interval, 2.56-2.80) and 3.08 (2.84-3.11), respectively, for X rays, and 2.39 (2.38-2.43) and 2.72 (2.69-2.75), respectively, for protons (P