摘要目的 了解胃癌术后放疗患者中自由呼吸运动对放疗靶区移动程度,分析采用主动呼吸控制(ABC)方法后靶区移动程度及相关因素.方法 22例胃癌患者术中在瘤床或淋巴结引流区放置银夹作为标记,术后采用ABC技术定位放疗.每周重复2次采集自由呼吸和ABC时相0°和90°图像,应用Image J图像处理软件处理图像及标记银夹.测定自由呼吸和采用ABC时银夹在头脚、左右及前后轴向上的移动幅度,包括同次放疗内和分次放疗间移动幅度.结果 自由呼吸和采用ABC后头脚、左右、前后轴向上的移动幅度分别为11.1、1.9、2.5 mm(F=85.15,P=0.000)和2.2、1.1、1.7 mm(F=17.64,P=0.000),头脚、前后方向明显减少(t=4.36,P=0.000;t=3.73,P=0.000);同次放疗内自由呼吸与ABC后同一呼吸相内的无变化,而ABC后异次呼吸相内的分别为3.7、1.6、2.8mm(F=19.46,P=0.000),3个方向均明显增加(t=-4.36,P=0.000;t=-3.52,P=0.000;t=-3.79,P=0.000);ABC后分次放疗间的银央簇中心和银夹最大移动幅度分别为2.7、1.7、2.5 mm(F=4.07,P=0.019)和4.6、3.1、4.2 mm(F=5.17,P=0.007),3个方向均明显增加(t=-4.09,P=0.000;t=-4.46,P=0.000;t=-3.45,P=0.000).结论 胃癌术后自由呼吸状态下放疗靶区移动幅度以头脚方向最大,左右方向最小;采用ABC技术后头脚、前后方向明显减小,而同次治疗内和分次放疗问的也有类似变化.

abstractsObjective To assess the impact of respiratory motion on the displacement of target area and to analyze the discrimination between free breathing and active breathing control (ABC) in patients with gastric cancer treated with post-operative radiotherapy. Methods From January 2005 to November 2006, 22 patients with post-operatively confirmed gastric cancer were enrolled in this study. All diseases were T_3/ N +, staging Ⅱ - Ⅳ. Patients were CT scanned and treated by radiation with the use of ABC. Image J software was used in image processing, motion measurement and data analysis. Surgical clips were implanted as fiducial marks in the tumor bed and lymphatic drainage area. The motion range of each clip was measured in the resultant-projection image. Motions of the clips in superior-inferior (S-I), right-left (R-L) and anterior-posterior (A-P) directions were determined from fluoroscopy movies obtained in the treatment position. Results The motion ranges in S-I, R-L and A-P directions were 11.1 mam, 1.9 mm and 2.5 mm (F = 85.15, P = 0. 000) under free breathing, with 2.2 mm, 1.1 mm and 1.7 nun under ABC (F = 17.64, P = 0. 000), and the reduction of motion ranges was significant in both S-I and A-P directions (t = 4.36, P = 0. 000;t = 3.73,P = 0.000). When compared with under free-breathing, the motion ranges under ABC were kept unchanged in the same breathing phase of the same treatment fraction, while significant increased in different breathing phase in all three directions (t = - 4.36, P = 0. 000; t = - 3.52, P = 0.000; t =-3.79, P = 0. 000), with a numerical value of 3.7 mm, 1.6 mm and 2.8 mm, respectively (F = 19.46, P = 0. 000) . With ABC between different treatment fractions , the maximum displacements were 2.7 mm, 1.7 mm and 2.5 mm for the centre of the clip cluster (F =4.07,P =0. 019), and were 4.6 mm, 3.1 mm and 4.2 mm for the clips (F =5.17 ,P =0.007). The motion ranges were significant increased in all the three directions (t = - 4.09, P=0.000 ; t =-4.46, P = 0.000 ; t = - 3.45, P =0.000). Conclusions In the irradiation of post-operative gastric cancer, the maximum displacement of organ motions induced by respiration is in S-1 direction and the minimum in R-L direction under free breathing. The use of ABC can reduce the motions significantly in S-I and A-P directions, and the same changes exist in both inter-and intra-fraction treatment.