Detector729在放射治疗剂量学中的应用研究

Application of Detector729 in radiotherapy dosimetry

摘要:

目的：探讨二维电离室矩阵探测器Detector729剂量测量的准确性及其在放射治疗质量控制中的应用。方法：采用0.6 cm3的参考电离室在X射线下对Detector729进行剂量刻度，然后两者进行剂量和输出因子测量比对，最后应用Detector729对调强放射治疗（intensity modulated radiation therapy，IMRT）治疗计划进行实际机架角剂量验证。结果：参考电离室对Detec－tor729电离室的刻度因子是0.991，两者测量结果比对相对测量偏差≤ 0.57%，在4 cm×4 cm~ 20 cm×20 cm不同方形野下输出因子测量结果基本一致，应用Detector729对IMRT剂量验证的γ通过率均＞90%。结论：应用Detector729进行放疗剂量测量和质量控制工作，结果具有较高的准确度和可信度，可为规范我国放疗剂量测量工具的使用提供理论依据。

Abstract:

Objective：To study accuracy of 2-D matrix Detector729 in dosimetric measurement and its application in radiotherapy quality control. Methods：Tests and output factor measurement were performed to evaluate and compare the accuracy of Detector729 taking 0.6 cm3 ion chamber under the X-ray as reference. Detector729 was used as a tool to verify dosimetric distribution for inten－sity modulated radiation therapy（IMRT）. Results：The scale factor of Detector729 from the reference ionization chamber was 0.991，and the comparison results showed the maximum deviation of measuring point dose was 0.57%. Meanwhile，under the square fields of 4 cm×4 cm-20 cm×20 cm，the estimated output factor matched very well with the reference ion chamber measurements. Conclusion：With high accuracy and reliability，Detector729 can be used in dosimetric measurement and quality control of radiotherapy and pro－vide theoretical basis for the standard use of radiation dosimetric measurement instruments.