CAJ | 학술논문

目的探讨模拟校位融合(SF)、自动+目视校准融合(AF)和骨性融合(BF)方法对鼻咽癌IMRT中剂量分布变化影响.方法 15例Ⅲ-Ⅳa期采用IMRT的鼻咽癌患者于放疗前和放疗20 ～ 25次时行螺旋CT模拟定位扫描,将2次图像分别采用3种融合方法进行融合,以放疗前图像治疗中心点在3种融合方法下第2次图像投影点作为重新计算剂量的治疗中心,将原计划分别移植到第2次图像上进行正向计算并形成新的剂量分布.计算3种融合方法融合参数之间的绝对差值平均值,对靶区及正常组织剂量变化进行配对t检验.结果 SF与AF的平行轴移动绝对差值平均值＜0.13 cm、旋转移动角度＜0.40°,BF旋转角度＞0.71°.3种融合方法对剂量分布变化影响总趋势相似,但BF对颈部的影响较大[GTVnd的D95减少(P=0.039)].BF下脑干Dmax、D1cm3有不变或呈增加趋势,而其他两种融合方法的呈下降趋势.结论不同融合方法对鼻咽癌IMRT中剂量变化会造成影响,应该关注并说明所使用融合方法.SF与AF剂量变化趋势相似,更接近于实际治疗情况.
목적 탐토모의교위융합(SF)、자동+목시교준융합(AF)화골성융합(BF)방법대비인암IMRT중제량분포변화영향.방법 15례Ⅲ-Ⅳa기채용IMRT적비인암환자우방료전화방료20 ～ 25차시행라선CT모의정위소묘,장2차도상분별채용3충융합방법진행융합,이방료전도상치료중심점재3충융합방법하제2차도상투영점작위중신계산제량적치료중심,장원계화분별이식도제2차도상상진행정향계산병형성신적제량분포.계산3충융합방법융합삼수지간적절대차치평균치,대파구급정상조직제량변화진행배대t검험.결과 SF여AF적평행축이동절대차치평균치＜0.13 cm、선전이동각도＜0.40°,BF선전각도＞0.71°.3충융합방법대제량분포변화영향총추세상사,단BF대경부적영향교대[GTVnd적D95감소(P=0.039)].BF하뇌간Dmax、D1cm3유불변혹정증가추세,이기타량충융합방법적정하강추세.결론 불동융합방법대비인암IMRT중제량변화회조성영향,응해관주병설명소사용융합방법.SF여AF제량변화추세상사,경접근우실제치료정황.
Objective To compare the dosimetric effects of simulation and correction fusion (SF),automatic and visual correction fusion (AF),and bone fusion (BF) during the course of intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC).Methods Fifteen patients with stage Ⅲ-Ⅳa NPC treated with IMRT had planning CT scans before and after 20-25 fractions of radiotherapy.SF,AF,and PF methods were separately used to undertake the fusion between the first and second planning CT images.New treatment isocenters were the shadow cast of the initial isocenter on the second planning CT images with the three fusion methods;initial treatment planning was transferred to the second planning CT according the new treatment isocenter,and new dosimetric distribution was calculated.The fusion parameters of the three fusion methods,as well as dosimetric changes in the target volume and normal tissue,were compared with paired t-test.Results There were relatively small differences in fusion parameters between SF and AF methods;the paired difference means in translation in all directions were less than 0.13 cm,and the paired difference means in rotation in all directions were less than 0.40 degree.BF fusion parameters differed widely from others,especially in rotation,and the paired difference means were more than 0.71 degree.The three fusion methods have similar dosimetric effects on the target volume and normal tissue,but had a significant dosimetric effect on the neck region,with a significant decrease in GTVnd D95 (P =0.039).Dmax and D1 cm3 for the brain stem remained unchanged or showed an increasing trend with the BF method,but they showed a decreasing trend with the SF and AF methods.Conclusions Different fusion methods would lead to different results in the research on dosimetric changes in the target volume and normal tissue during the IMRT for NPC,so the fusion method should be introduced in the reports of these research.The BF method is not recommended because its dosimetric effect on the neck region is great,resulting in a big difference from the actual dose distribution.The SF and AF methods have similar dosimetric effects,which are close to the actual situation.