摘要
目的:探讨利用MV级计算机X线摄影(computed radiography,CR)技术拍摄放射治疗病人射野验证片的价值与意义。材料与方法:采用双曝光技术进行放射治疗射野验证片的拍摄,在曝光时加入射野参考坐标十字插板,十字线坐标为实际射野的参考坐标,并根据片中人体解剖标记计算中心移位误差,与模拟机的计划摄片、治疗计划系统生成的DRR(digital reconstructed radiography)进行比较分析,测量摆位误差。结果:15例病人,在首次进行放射治疗前用AGFA高能CR分别拍摄0°和90°验证片,共得到30张验证片。模拟定位片和射野验证片都能较清晰显示照射野形状、大小、治疗中心以及与人体解剖标记之间的关系。由两位医师得出的两组误差数据没有统计学差异(在x、y、z方向上,P>0.05)。结论:利用CR技术拍摄放疗病人模拟定位片和射野验证片,成像满意,操作简便,可以有效减少放疗摆位误差,提高摆位的准确性,及时纠正摆位误差,是质量控制和质量保证的有力工具。作为放射治疗病人位置的验证、实现放射治疗科数字化具有积极的意义。
Objective： To evaluate the value of megavolt computed radiography techniques for portal field verification in radiation oncology department. Material and Methods： Double-exposure technique was used to take the portal images. The portal images were screened using the AGFA CR, and the error was analyzed by comparing the portal image with digitally recon-structed radiographys （DRR） from the treatment planning system （TPS） and simulation image from simulator. The reference mark points were added to the field at the first exposure and the cross lines drawn based on the images were defined as the reference coordinate to the actual field. All verification images were acquired with （1-2）MU using 6 MV X-ray. Results： 30 images of 15 patients were taken by AGFA MV CR before radiotherapy. The CR images and simulator images can display the field shape, size, treatment center and anatomy structure clearly. All different structures and positions could be identified in order to assess if the actual field coincided with the radiation planning. Two groups of datum were compared to exclude the statistic difference, and the result is negative （ P〉0.05 in x, y and z axis）. Conclusions： It was satisfactory using MV CR technique for the radiotherapies patient＇s portal field image. The technique for patient position verification was effective. CR is a convenient method to realize digitalization in radiation oncology department.
出处
《中国医学物理学杂志》
CSCD
2009年第5期1389-1390,1408,共3页
Chinese Journal of Medical Physics
关键词
计算机X线摄影
射野验证
质量控制
computed radiography
radiotherapy
portal verification
