基于XVI技术对食管胸中段癌放疗摆位误差的分析  

Analysis on the positioning errors of mid - thoracic esophageal carcinoma radiotherapy using XVI

作　　者：张建宇[1] 丁涤非[2] 周玉凤[1] 曹海英[1] 刘永新[1] 洪君[1] 

机构地区：[1]中国人民解放军第八二医院肿瘤科,江苏淮安223001 [2]中国人民解放军第一二三医院肿瘤科,安徽蚌埠233010

出　　处：《徐州医学院学报》2016年第8期520-522,共3页Acta Academiae Medicinae Xuzhou

摘　　要：目的利用X射线容积图像（X—rayvolumeimage，XVI）技术分析食管胸中段癌放疗中的摆位误差大小，并据此计算出临床靶区体积外放值（marginclinicaltargetvolume，MCTV）。方法54例食管胸中段癌患者，均接受三维适形放射治疗（3-dimensionalconformalradiationtherapy，3D—CRT）或调强放射治疗（intensitymodulatedradiationtherapy，IMRT），每位患者治疗前均用XVI技术采集图像，疗程中每周随机扫描2次，连续采集3周，即每位患者共采集6幅图像。将重建扫描图像与治疗计划cT扫描图像相配准，得出当次患者x（左右）、Y（头脚）、z（腹背）三个方向上的摆位误差，进行在线移床校准，记录校准前后三个方向的摆位误差。根据vanHerk提出的MCTV公式（MCTV=2．5∑＋0．7σ）进行计算。结果54例患者共扫描324幅图像。校准前x、Y、z三个方向的摆位误差分别为（-0．01±1．12）mm、（0．74±3．47）mm、（-0．82±1．26）mm，校准后x、Y、z三个方向的摆位误差分别为（-0．01±0．42）mm、（0．08±0．61）mm、（-0．02-e0．35）mm；不应用XVI技术时MCTV在X、Y、Z三个方向的值分别为4．16mm、9．42Bin、4．47nlm，应用XVI技术时MCTV在x、Y、z三个方向的值分别为1．38mm、1．62mm、1．39mm。结论对食管胸中段癌患者在治疗前应用XVI技术校准，可以减小人为摆位误差，缩小MCTV，从而减小放疗计划靶区体积。Objective To analyze the positioning errors of mid - thoracic esophageal carcinoma radiotherapy using X -ray volume image （XVI） and calculate margin clinical target volume （MCTV）. Methods A total of 54 patients with mid - thoracic esophageal carcinoma were enrolled into the current study. They underwent either 3 - dimensional confor- real radiation therapy （3D -CRT） or intensity modulated radiation therapy （IMRT）. Their images were collected using XVI before treatment. Each patient was randomly scanned twice per week for three consecutive weeks, with 6 images for each one in total. Then, reconstructed scanning images were matched with CT scanning images, and the positioning er- rors in the three directions X （left and right） , Y （head and foot） , and Z （abdomen and back） were obtained. The on- line moving bed calibration was carried out and the resultant positioning errors in the three directions were recorded. The outer area was calculated according to the following equation： MCTV=2.5∑＋0.7σ. Results There were a total of 324 images for all patients. Before calibration, the positioning errors of the X, Y, Z directions were （ -0. 01 ±1.12） mm, （0.74 ± 3.47） mm and （ - 0.82 ± 1.26） ram, respectively. After calibration, the positioning errors of the X, Y, Z directions were （ -0.01 ±0.42） ram, （0.08 -0.6） mm and （ -0.02 ±0.35） mm. Without XVI, the MCTV of the X, Y, Z directions were 4.16 mm, 9.42 mm and 4.47 ram. Using XVI, the MCTV of the X, Y, Z directions were 1. 38 mm, 1.62 mm and 1.39 mm. Conclusions XVI - based calibration before treatment can be applied for mid - tho- racic esophageal carcinoma patients. With reduced positioning errors and smaller MCTV, this approach can decrease the volume of the planning target area.

关 键 词：X射线容积图像 图像引导放疗 摆位 误差 食管胸中段癌 

分 类 号：R730.55[医药卫生—肿瘤]