治疗计划系统的黑度计功能

目的： 本文探讨用放射治疗计划系统配备的透射扫描仪和相应黑度计软件获得剂量学参数的方法。方法： Ｋｏｄａｋ ＸＶ２ 胶片在ＳＬ７５／１４ 加速器不同射野曝光，再冲洗，扫描获得黑度图像，转化为剂量分布，从而得到射野大小，半影宽度，离轴比曲线（ＯＣＲ） ，中心轴百分深度剂量（ＰＤＤ） ，测量数据与三维射野分析仪的结果比较。结果： 用黑度计功能测量射野大小与射野分析仪测量差别不大于２ ｍ ｍ ；测量半影差别不大于０５ ｍ ｍ ；测量ＯＣＲ曲线位置相差不大于３ ｍ ｍ 。结论： 应用扫描仪和相应黑度计功能，可以测得放射治疗设备的剂量学参数，可替代三维水箱的部分功能

Optical density function in radiation therapy planning system

Objective: A method was used for measurement of the dosimetric parameters by transparency scanner and related software.Methods: Kodak XV2 films radiated in the fields of accelerator SL75/14 were developed and scanned by transparency scanner.Then the sensitometric curves were converted to a dose distribution by the software.The field size,the penumbra,OCR curve and PDD curve were obtained and compared with the dosimetric data measured by three dimension field analyzer.Results: The field size measured by optical density had high coincidence with the ones by field analyzer with accuracy of 2 mm.The penumbras were agreed well within 0.5 mm.The OCRs were agreed well within 3 mm.Conclusion: It is possible to measure the dosimetric parameters by scanner and optical density software and to replace the part function of field analyzer.