利用参考层面提高CT模拟复位的精确度

目的 探寻先比较参考层面影像再确定放疗计划射野中心的方法来提高复位精度,并建立适应本科室的鼻咽癌和宫颈癌放疗计划射野中心复位误差的参考标准.方法 对50例鼻咽癌和20例宫颈癌患者放疗计划射野中心复位,比较放疗定位时与复位时参考层面和计划中心层面的影像,测量并计算各距离之差.结果 90%以上鼻咽癌病例各距离差值＜2 mm(范围0～2 mm);80%以上宫颈癌计划满足△MU1'和△MU2'均≤5 mm(范围1～5 mm)且其他各差值≤3 mm(范围1～3mm).结论 通过比较两组影像确定计划中心位置提高了放疗定位和复位扫描的一致性,有效保证了复位精度,增加复位时中心点位置体表标记的可信度.建立鼻咽癌计划中心各方向误差＜2 mm,宫颈癌计划中心△MU1'≤5 mm,△MU2'≤5 mm且其他各差值≤3 mm的复位标准是可行的.

Abstract：

Objective To explore a new method of comparing the references images first to enhance the precision of the central point of the radiation treatment planning(RTP), try to establish a reference standard for this method in the nasopharyngeal cancer(NPC)and carcinoma of utercin cervix in the work of position verification. Methods For 50 RTPs of NPC and 20 RTPs of carcinoma of utercin cervix, the reference-CT-images in set-up and in position verification were compared, and to measure the difference between the two images. Then, in the same way, compare and measure the difference in the central-pointimages. Results For NPC, there was over 90% RTPs in which every difference measured was less than 2 mm;for carcinoma of utercin cervix, over 80% RTPs meet the criterion:the value of △MU1 ' or △MU2' was less than 5 mm and the others are less than 3 mm. Conclusions By comparing the references-CT-images in set-up and in position verification, the precision of the central point of the RTP is enhanced. The marks on the skin become more credible. So, it is feasible to perform the criterions in the work of position verification:for NPC every difference measured is less than 2 mm;for carcinoma of utercin cervix the value of △MU1 ' or △MU2 ' is less than 5 mm and the others are less than 3 mm.

A clinical study for radiotherapy positioning with references images on CT simulator

Objective To explore a new method of comparing the references images first to enhance the precision of the central point of the radiation treatment planning(RTP), try to establish a reference standard for this method in the nasopharyngeal cancer(NPC)and carcinoma of utercin cervix in the work of position verification. Methods For 50 RTPs of NPC and 20 RTPs of carcinoma of utercin cervix, the reference-CT-images in set-up and in position verification were compared, and to measure the difference between the two images. Then, in the same way, compare and measure the difference in the central-pointimages. Results For NPC, there was over 90% RTPs in which every difference measured was less than 2 mm;for carcinoma of utercin cervix, over 80% RTPs meet the criterion:the value of △MU1 ' or △MU2' was less than 5 mm and the others are less than 3 mm. Conclusions By comparing the references-CT-images in set-up and in position verification, the precision of the central point of the RTP is enhanced. The marks on the skin become more credible. So, it is feasible to perform the criterions in the work of position verification:for NPC every difference measured is less than 2 mm;for carcinoma of utercin cervix the value of △MU1 ' or △MU2 ' is less than 5 mm and the others are less than 3 mm.