鼻咽癌螺旋断层治疗的剂量学研究  

A dosimetric study of helical tomotherapy for nasopharyngeal carcinoma

作　　者：曹新格 王雅棣[1] 张勇乾[1] 张富利[1] 高军茂[1] 

机构地区：[1]北京军区总医院放疗科,100700

出　　处：《中华放射肿瘤学杂志》2016年第8期802-806,共5页Chinese Journal of Radiation Oncology

摘　　要：目的：通过HT观察鼻咽癌患者放疗过程中肿瘤及OAR的照射剂量与计划剂量的差别，为临床提供帮助。方法对21例采用HT根治性放疗的鼻咽癌患者，于CT下定位并勾画靶区及OAR。每次治疗前均进行MVCT扫描，应用MVCT图像在HT的自适应模块上进行剂量重建，得到当次的受照剂量，并模拟出该次无图像引导下的受照剂量；将各单次剂量分布和对应的融合CT图像传输至形变软件MIM6.0中进行剂量叠加，得到总照射剂量。将初始计划定义为Plan-1，图像引导的计划为Plan-2，无图像引导的计划为Plan-3，t检验或Wilcoxon符号秩检验三者靶区、OAR的剂量分布情况。结果图像引导下的Plan-2较Plan-1的pGTV、PTV-1的D98分别降低1.16％、2.3％（ P＝0.025、0.043）；左右腮腺体积平均缩小46.0％、46.5％（ P＝0.000）；左右腮腺质心距体中线垂直距离分别缩短6.9％、6.5％（P＝0.000）；双侧腮腺的V26、Dmean分别升高32.8％和25.2％（P＝0.000）。无MVCT引导的Plan-3较Plan-1的pGTV、PTV-1、PTV-2的D98分别降低2.0％、1.9％、2.4％（ P＝0.001、0.007、0.036）；双侧腮腺的V26、Dmean分别升高33.6％、25.3％（ P＝0.000）；脊髓Dmax升高6.9％（ P＝0.005）。Plan-2中脊髓的D2与Plan-1相近（ P＝0.392）。结论鼻咽癌HT过程中双侧腮腺剂量升高，且与腮腺向体中线移位密切相关。图像引导对于靶区剂量获益并不大，但可减少脊髓受量。Objective To use helical tomotherapy （ HT ） for determining the difference between actual doses and planning doses to the target volume and organs at risk （ OARs ） in patients with nasopharyngeal carcinoma receiving radiotherapy, and to provide guidance for the clinical treatment. Methods Localization and delineation of the target volume and OARs were performed by computed tomography （ CT） in 21 patients with nasopharyngeal carcinoma receiving radical radiotherapy using HT. All patients underwent megavoltage CT （ MVCT） scan prior to treatment. The obtained MVCT images were used for dose reconstruction in the adaptive module of HT, in which the actual dose was obtained and the non-image-guided dose was simulated. Each single dose distribution and the corresponding CT image were sent to software MIM6. 0 for superimposition, and the overall dose was obtained. The initial plan, image-guided plan, and non-image-guided plan were named Plan-1, 2, and 3, respectively. The dose distribution in the target volume and OARs was compared between the three plans with t - test or wilcoxon test . Results Compared with those in Plan-1, the D98 values for the planning gross tumor volume （ PGTV） and planning target volume （ PTV） in Plan-2 were significantly reduced by 1. 16% and 2. 3%, respectively （ P=0. 025;P=0. 043）;the volumes of the left and right parotids in Plan-2 were significantly reduced by 46. 0% and 46. 5% on average, respectively （ P=0. 000）;the distances between the midline and the center-of-mass for left and right parotids were significantly reduced by 6. 9% and 6. 5%, respectively （ P=0. 000）;the V26 and Dmean for both parotid glands were significantly elevated by 32. 8% and 25. 2%, respectively （ P=0. 000） . Compared with those in Plan-1, the D98 values for PGTV, PTV-1, and PTV-2 in Plan-3 were significantly reduced by 2. 0%, 1. 9%, and 2. 4%, respectively （ P=0. 001;P=0. 007;P=0. 036）;the V26 and Dmean for both parotid glands in Plan-3 were significantly elevated by 33. 6

关 键 词：鼻咽肿瘤/螺旋断层疗法 图像引导 形变图像配准 剂量学 

分 类 号：R739.63[医药卫生—肿瘤]