二维整体挡铅块制作技术改进与临床应用

摘要

Objective : To investigate the technique improvement of two-dimension integral blocks designing hy using computer image processing techniques and its clinical application. Methods : 79 Patients were photographed x-ray positioned film ( amplification ratio = 1. 4 ) on analog machine and the target volumes were drawn out, and then 42 cases( the study group ) were drawn the target volume of positioned film shape and central cross-wire on a blank paper. This was named SFD picture. We scanned the SFD picture and edited it by Photoshop and then printed copies at the proportion of 1 and 0. 65 which were named SAD picture and STD picture respectively. According to SAD picture we cut the plastics on manual cutting machine and so we made conformal blocks. The other 37 cases’( the control group ) conformal blocks were made by routine designing technique. Results : With this method we could design low melting conformal blocks with any shape and size. which had inner hore diameter of 30cm. Comparing with SAD picture, irregular margins’ size of conformal Cerrobend block was quite precise and the difference between them was less than 1mm. The efficiency of sticking blocks was the same as on the accelerator. The recent therapeutic effect and the acute radiotherapy reaction of the study group andthe control group were regular, and with no statistical difference( P ＞ 0. 05 ). Conclusion: Computer image technique is applied to design the conformal blocks, and to take the place of the way of sticking hlocks on accelerator. With this technique, two-dimension integral conformal block can be made quickly and accurately, and at the same time the work process has been simplified and the work efficiency improved. This new technique is worthy of spreading.%目的:探讨用电脑图像处理技术改进二维整体挡铅块制作技术.方法:79例患者在模拟定位机上拍摄放大率为1.4的X线定位胶片,勾画靶区,然后42例(研究组)将定位胶片的靶区形状和中心十字线描在空白纸上,此图形定义为SFD图.扫描仪对SFD图进行扫描,用Photoshop软件编辑并分别打印出比例为1的图形,定义为SAD图和比例为0.65的图形定义为STD图,作为"粘铅图".用SAD图在手动热丝切割机上切割塑料泡沫,制作适形铅挡块.另37例(对照组)用常规技术制作适形铅挡块.结果:用此方法可以制作内孔径30cm,任意形状和大小的低熔点适形铅挡块.适形铅挡块所形成不规则野边缘与SAD图相比,其误差小于1mm,与在加速器上粘铅效果相同.研究组和对照组近期疗效和急性不良反应差异无统计学意义.结论:将电脑图像处理技术用于制作适形铅挡块,代替在加速器上粘铅,可以快速准确地制作二维整体适形铅挡块,简化了制作流程,提高了工作效率,值得推广应用.