二维电离室矩阵在放疗的质量保证体系中的应用

肿瘤的放射治疗中，为了检测治疗设备的性能以及确保放疗计划实施的可靠性和准确性，必须具备完善的质量保证体系（Quality Assurance，QA）. 本文研究将德国PTW公司研发的二维电离室矩阵Seven29应用到放疗的日常QA过程中，使用Seven29和与之配套的八角体模或平板体模来测量剂量分布图，并与治疗计划系统计算出来的剂量分布图进行比较. 对治疗设备每月的QA，最重要的项目是检测射线性能的连续性，检测方法是对连续两个月机器性能的参数进行比较. 采用PTW公司的软件VeriSoft和MultiCheck进行数据分析，经大量的实验验证和比较，结果表明二维电离室矩阵是剂量测量和分析的有效工具，其精度高、可靠性强、使用方便，是实现无胶片化和无纸化放疗体系的重要组成部分.

Application of 2D Ion Chamber Array in Quality Assurance of Radiation Therapy

The Quality Assurance（QA）in the treatment of malignant diseases is highly required in the processes of periodical machine performance evaluation and patient-specific dose distribution verification for the safe and accurate radiation therapy. This study aims to evaluate the performance of the PTW ion chamber array Seven29 in routine QA procedures. The method for the study is to use Seven29 with the dedicated Octavius phantom and slab phantom in the dose distribution measurement for the verification of the dose map computation on the treatment planning systems. PTW software VeriSoft and MultiCheck are used for the analysis. Beam profile consistency check，one of the most important items for LINAC monthly QA，can be directly evaluated between two consecutive months. Ion chamber array has proven to be an accurate，reliable and efficient physics gadget for various dosimetry verification procedures. It is one of the essential components of a paperless and filmless radiation therapy facility.