医用直线加速器物理楔形板的质控方法研究

Study on quality control method of wedge filter for linear accelerator in radio therapy

目的:研究并设计放射治疗设备医用直线加速器中楔形板使用技术的质量控制方法,以保证放射治疗的精确执行,从而提高肿瘤控制率。方法:分析在使用楔形板时可能导致剂量出现误差的原因,并实际测量某院直线加速器不同机架角度和不同准直器角度组合下楔形野和平野照射时的吸收剂量,分别计算楔形野和平野下的楔形板运动重复性和到位精度。结果:实验证明,某院直线加速器楔形板运动重复性和到位精度达到相关技术标准,可以安全使用。结论:楔形板的运动重复性和到位精度是放射治疗质量保证体系中的一项重要内容,该质控方法可作为楔形板的常规质量控制方法,填补了该领域空白。

Objective To investigate and design quality control method of the wedge filter in the radiotherapy. Methods The factors might result in dose errors were analyzed, and the absorbed doses in wedge field and open field were measured with different gantry angles and collimator angles of the linear accelerator in some hospital. The repeatability and positioning accuracy of wedge filter were calculated in wedge field and open field. Results Experiments showed the linear accelerator wedge filter had the repeatability and positioning accuracy meet the technical standards. Conclusion The repeatability and positioning accuracy of wedge filter are important parts of the quality assurance system in the radiotherapy. This method can be used as routine quality control method.