CT on rail在宫颈癌图像引导放射治疗中的应用

发布时间：2018-07-05 13:02

  本文选题：CT + on　； 参考：《安徽医科大学》2017年硕士论文

【摘要】：目的1.比较宫颈癌图像引导放射治疗(IGRT)中滑轨CT(CT on rail)与电子射野影像系统(EPID)测量的摆位误差,评价CT on rail在宫颈癌IGRT中的应用价值;2.比较CT on rail引导宫颈癌IGRT时,膀胱不同的充盈状态对靶区与危及器官(OAR)的剂量分布的影响。方法随机选取在我院进行宫颈癌调强放疗(IMRT)的患者15例,每周先在膀胱充盈状态下(定位前2小时排空膀胱并一次性饮水500ml)扫描一次EPID正侧位片和CT on rail图像,将EPID拍摄的正侧位片与数字重建影像系统(DRR)进行配准,CT on rail图像与计划CT图像分别进行灰度配准和骨性配准,得到三组X(左右)、Y(头脚)、Z(腹背)方向的线性摆位误差,并计算各个方向的CTV-PTV外放间距(MPTV),然后排空膀胱,再进行一次CT on rail图像扫描,并将两次所得CT图像均传送至三维治疗计划系统(TPS),进行靶区勾画及设计治疗计划,得到在膀胱充盈与空虚状态下,两组临床靶区(CTV)与直肠、膀胱等危及器官(OAR)的剂量学参数,最终所得数据进行统计学分析。结果1.EPID,CT on rail骨性及灰度配准三种方式测量的X轴摆位误差分别为0.251±0.065,0.209±0.536,0.184±0.046cm,Y轴摆位误差分别为0.379±0.044,0.256±0.060,0.204±0.051cm,Z轴摆位误差分别为0.185±0.051,0.112±0.057,0.126±0.058cm,CT on rail灰度配准组与骨性配准所测摆位误差均明显小于EPID组(P0.05),灰度配准组在X,Y轴的摆位误差较骨性配准组缩小,尤其在Y轴上(P0.05),两者在Z轴的摆位误差无明显差别;三组在X轴的MPTV为0.67、0.56、0.49cm,Y轴的MPTV为0.98、0.68、0.54cm,Z轴的MPTV为0.50、0.32、0.35cm;2.CT on rail引导宫颈癌IGRT时,膀胱充盈与空虚状态相比,两组的CTV平均剂量(CTV Dmean)分别为5057.50±91.09,5039.08±88.31c Gy,CTV最大剂量(CTV D2)分别为5353.50±64.20,5341.05±70.37 c Gy,两组数据间无明显差异(P0.05);两组的膀胱平均剂量(膀胱Dmean)分别为3606.00±146.36,4093.00±151.81c Gy,V40%分别为36.50±5.16,49.70±8.51,V45%分别为24.75±6.42,27.28±6.63,V50%分别为12.42±2.23,12.90±2.42,其中膀胱Dmean、V40、V45有显著差异(P0.05),膀胱V50无明显差异(P0.05);两组的直肠平均剂量(直肠Dmean)分别为3738.50±257.45,3804.00±309.18c Gy,直肠V40%分别为44.78±6.73,55.23±5.67,V45%分别为30.15±4.74,31.90±5.04,V50%分别为5.52±0.27,5.64±0.45,其中直肠Dmean,V40,V45的差异显著(P0.05),直肠V50无明显差异(P0.05)。结论1.在宫颈癌IGRT中,CT on rail较EPID能更好地测量摆位误差,使放疗靶区更为精准;在CT on rail引导宫颈癌IGRT时,采用灰度配准优于骨性配准,根据CT on rail灰度配准测量的摆位误差计算的X,Y,Z方向的MPTV可作为本中心宫颈癌放射治疗的参考;2.CT on rail引导宫颈癌IGRT时,膀胱充盈状态有利于对直肠、膀胱等OAR的保护,在分次治疗间应尽量保持膀胱充盈状态。
[Abstract]:Objective 1. To evaluate the application value of CT on rail in cervical cancer by comparing the error between CT on rail) and electron field imaging system (EPID) in cervical cancer guided radiation therapy (IGRT). To compare the effects of different filling states of bladder on the dose distribution of target area and endangered organ (OAR) in cervical carcinoma guided by CT on rail. Methods Fifteen patients with cervical cancer undergoing intensity modulated radiotherapy (IMRT) were randomly selected and scanned with positive and lateral CT scan and CT on rail images in the condition of bladder filling (emptying bladder 2 hours before positioning and one-time drinking 500ml) every week. Three groups of linear pendulum errors in the direction of X (left and right) Y (head and foot) and Z (ventral dorsal) are obtained by registration of CT on rail images and planned CT images with digital reconstruction image system (DRR) taken by EPID, respectively. The CTV-PTV outer space was calculated, then the bladder was emptied, the CT on rail images were scanned again, and the two CT images were transmitted to the three dimensional treatment Planning system (TPS) to draw the target area and design the treatment plan. The dosimetric parameters of clinical target area (CTV), rectum and bladder (OAR) were obtained under the condition of bladder filling and emptiness. The final data were analyzed statistically. Results 1. The axial pendulum errors measured by EPID-CT on rail bone quality and gray level registration were 0.251 卤0.065 卤0.209 卤0.536U 0.184 卤0.046 cm ~ (-1) Y and 0.379 卤0.044 卤0.060 ~ 0.256 卤0.060 ~ 0.204 卤0.051 cm Z axis pendulum errors of 0.185 卤0.051 卤0.112 卤0.057 ~ 0.126 卤0.058 cm CT on rail gray level registration group respectively. In the EPID group (P0.05), the error of the shafts of the gray level registration group was smaller than that of the bone registration group. Especially on the Y axis (P0.05), there was no significant difference between the two groups in the Z axis, and in the three groups, the MPTV of the X-axis was 0.670.56 ~ 0.49 cm ~ (-1) Y axis was 0.98 ~ 0.68 ~ 0.54 cm ~ (-1) Z axis was 0.50 ~ 0.32 ~ 0.35 cm ~ (35) cm ~ (2) CT on rail guiding cervical carcinoma, the bladder filling was compared with the emptiness state. 涓ょ粍鐨凜TV骞冲潎鍓傞噺(CTV Dmean)鍒嗗埆涓，

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