一种用于三维辐照剂量检测的光学CT技术  

An Optical CT Technology for 3D Radiation Dose Verification

作　　者：王培玮[1] 王贤刚[2] 徐沔[1] 

机构地区：[1]中国计量科学研究院,北京100013 [2]清华大学核能与新能源研究院,北京100084

出　　处：《CT理论与应用研究（中英文）》2009年第1期63-68,共6页Computerized Tomography Theory and Applications

摘　　要：放射治疗已经发展到3D适形和调强阶段,使得剂量不但具有3D空间分布而且随时间变化,传统的3D水箱的静态测量方式已经不能满足剂量验证的要求。本论文提出了用组织等效性好的辐射敏感材料制成模体,模体辐照后产生辐射效应并存储空间剂量分布信息,然后采用OCT读出剂量分布,从而完成测量任务,发展成3D凝胶剂量学。本课题设计研制了用于聚合物凝胶模体3D剂量检测的光学CT系统,采用锥束投照扫描,帧投影采集方式,对约580 nm波长可见光的衰减系数进行图像重建,并在此基础上描绘等剂量图等放疗临床需要的剂量学资料。OCT的扫描重建时间,分辨能力,剂量响应等都得到满意的结果。采用自制的MAGIC测量模体,用6 MV医用加速器的X射线进行照射,空间剂量分布信息存储稳定,并得到满意的剂量图。Modern radiotherapy requires new approaches to dosimetry. The dosimeters must be able to assess the dose not only in a point but also in complex three-dimensional objects. Recently 3D Gel dosimetry using a tissue- equivalence phantom to record dose stereo-distribution then to acquire 3D dose data with MRI and optical evaluation techniques is a highly promising tool to address the emerging needs of radiotherapy dosimetry. An optical CT system used to scanning 3D dose distribution in a polymer gel has been designed. The optical CT system has a cone light beam （580nm） scanner, a CCD camera to acquire the project data and a PC for scan control and for mapping of 3D dose distributions. Scan time and reconstruct time, resolution and dose respond are practically satisfaction. The polymer gel dosimeter is a MAGIC phantom. The irradiation of gel dosimeter was performed using a 6 MV accelerator X-ray with a field size of 3 cm × 3 cm. The dose information is stable. The dose distribution map acquired is satisfaction.

关 键 词：光学CT 辐射敏感凝胶 3D凝胶剂量学 剂量图 放疗剂量学 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]