辐射野特性微机检测方法的研制

The study of measurement method of radiation fields characteristics with computer technique

目的根据感光图像的灰度值与吸收剂量有一定关系的原理,研制一个辐射野特性检测系统,通过对感光图像检测,测定出辐射野内剂量分布情况。方法将研制的计算机程序安装到配有扫描仪和彩色打印机的微机上,按一定顺序输入感光图像通过计算机指令,对感光图像进行检测。结果通过对感光图像的检测,对于与射线束垂直的平面,可获得该平面两主轴和两对角线的离轴剂量分布曲线。对于与射线束中心轴平行的中心平面,能获得该平面中心轴上的深度剂量分布曲线,并自动分析出表示辐射野特性的各项参数,同时还能以等剂量曲线的形式把检测平面内的剂量分布情况显示出来。结论用此系统对辐射野进行检测,能了解辐射野的剂量分布情况,是一种进行放射治疗质量保证(QA)与质量控制(QC)方便且实用的工具。

Objective To develop a test system of radiation field characteristics based on the relationship between grey scale and absorption dose of photosensitive picture. The conditions of dose distribution was mensurated by testing the photosensitive picture. Methods After our program was inputted to the computer,which lined to scanner and color printer, the photosensitive picture would be tested according to operater＇ s order. Results By testing the photosensitive picture, the off-axis dose distribution curves of two principal axis and two diagonal lines on the beam vertical plane were got. On the central plane which was paralleled to the beam, the central axis depth dose distribution curves were got. Many kind of parameters of radiation fields characteristics were calculated antommatically. At the same time,the dose distribution conditions were showed in isodose curves. Conclusion By testing radiation fields in this system, the dimemsional dose distribution condition of radiation fields can be realized. It is a convenient and useful tool for quality assurance （QA） and quality control （QC）.