电离室矩阵验证近距离治疗中放射源位置的准确性  

Location of radiation source in brachytherapy verified by ion chamber array

作　　者：谷珊珊[1] 王运来[2] 解传斌[2] 赵娜娜[2] 

机构地区：[1]武汉大学物理科学与技术学院,湖北武汉430072 [2]解放军总医院放疗科,北京100853

出　　处：《中国医学物理学杂志》2015年第4期586-589,共4页Chinese Journal of Medical Physics

摘　　要：目的:研究用电离室矩阵验证近距离治疗机192Ir源驻留位置的准确性。方法:使用Matrix Scan 1.1软件采集数据。塑料施源管拉直固定在二维电离室矩阵探测器面板上,选择中心电离室为测量参考电离室。以1 mm为间隔改变源的驻留位置,驻留时间固定为10 s,读取每个驻留位置的电离室读数,确定矩阵面板上中心电离室计数最大的源位置;分析电离室测量的剂量线性和重复性。设置±1 mm的源位置误差进行测量,利用Verisoft 5.0软件作γ分析,标准为3%/1mm,确定源的位置准确性。结果:同一个电离室重复读数以及电离室之间读数的偏差范围都在±1%以内,剂量仪读数与放射源的位置非线性变化,而且读数随放射源位置变化的灵敏度较高。电离室矩阵可以检测的源驻留位置的灵敏度在±1 mm以内。结论:电离室矩阵验证近距离治疗机192Ir源驻留位置结果准确,方法简单,成本低,可以用于后装治疗系统的质控。Objective To verify the reside of 192^Ir source in brachytherapy by ion chamber array. Methods All data were gathered by MatrixScan 1.1 software. The plastic applicator was straightened and fixed to the face plate of two-dimensional ion chamber array detector, and the central ion chamber was selected for reference measurement. The interval of the reside of radiation resources was 1 mm with a fixed irradiation of 1 0 seconds. And then the location of resources with maximum reading of central ion chamber in face plate among the readings of ion chamber array at every residents was confirmed. The dose linearity and reproducibility were evaluated. The ± 1 mm source location error were considered. The accuracy of source location was verified by gamma index analysis by Verisofi 5.0, with the dose-to-distance agreement of 3%/1 mm. Results The deviation range between duplicate reading for ion chambers and readings among ion chambers were within ~1%. The readings of an ion chamber was nonlinear with the locations of irradiation sources, and its sensitivity was quite high with the change of the locations. The sensitivity of the reside was within ±1mm detected by ion chamber array. Conclusion This ion chamber array can be applied in the quality control of brachytherapy system for it can verify the reside of 192^Ir source in brachytherapy, with simplicity and low cost.

关 键 词：近距离放射治疗 电离室矩阵 驻留位置 质量保证 

分 类 号：R454[医药卫生—治疗学] R812[医药卫生—临床医学]