中文摘要：

目的探讨自主呼吸控制（ABC）辅助适度深吸气呼吸控制（mDIBH）状态下勾画者和勾画时间对乳腺癌保乳术后全乳靶区的影响及放疗分次内和放疗分次间全乳靶区的位移。方法20例保乳术后拟行全乳调强放疗患者，ABC辅助CT模拟定位获得3个呼吸状态的5套CT图像[自由呼吸（FB）1套、适度深吸气呼吸控制（mDIBH）2套、深呼气呼吸控制（DEBH）2套]。放疗10～15次再获5套CT图像。5位放疗医师和同一放疗医师不同时间分别在初次定位获得的第1套mDIBH图像上勾画全乳靶区，比较勾画者和勾画时间对全乳靶区影响。分别标记初次定位2套mDIBH图像上术腔中全部银夹，比较全部银夹所构成几何体在分次内位移。分别勾画初次定位2套和重复定位第1套mD／BH图像上近乳腺靶区等中心平面的2条肋骨，通过比较所勾画肋骨感兴趣点（POI）空间位置位移，获得分次内和分次间胸廓扩张差异。结果同一医师不同时间勾画4次分别所得全乳靶区体积间差异无统计学意义，5位医师分别勾画全乳靶区体积差异有统计学意义（F=19．681，P=0．000）；同一mDIBH状态下，分次内全部银夹所构成几何体POI各方向位移差异无统计学意义，分次内肋骨POI各方向位移差异无统计学意义；同一mDIBH状态下，分次间肋骨POI各方向位移差异无统计学意义。结论不同勾画者所勾画全乳靶区差异是明显的。ABC辅助mDIBH状态下分次内及分次间全乳靶区位移在各个方向上的差异不明显。

英文摘要：

Objective To explore the influence of different delineators and different delineating time on target determination of the whole breast and to explore intrafraetion and inter：fraction target displacements of the breast on moderate deep inspiration breathing hold （mDIBH） assisted by active breathing control （ABC） after breast conservative surgery. Methods Twenty patients received primary CT-simulation assisted by ABC to get five sets of CT image on the three breathing condition which included one set from free breath （FB）, two sets from mDIBH and two sets frona deep expiration breathing control （DEBH）. After radiotherapy with ten to fifteen fractions, the repeat CT-simulation was carried out to get the same five sets of CT image as the primary CT- simulation. The whole breast target were delineated at different time by the same delineator and delineated respectively by five delineators on the first set of CT images got with mDIBH from the primary CT-simulation, and to compare the influence of delineator and delineating time on the whole breast target. The total silver clips in the cavity were marked respectively on the two sets of CT images got with mDIBH from the primary CT-simulation, and to compare the intrafraetion displacement of geometric body structured by the total of silver clips. The two ribs near the isocentrie plane of the breast target were delineated respectively on two sets of the mDIBH CT image from the primary. CT-simulation and on one set of the mDIBH CT image from the repeat CT-simulation, and comparing the movement of the point of interest （POI） of the ribs delineated to get the value of intrafraetion and interfraetion thoracic expansion. Results There was not statistically significant between the four volumes of whole breast targets delineated by the same delineator at different time, but with statistics significant between the volumes of whole breast target delineated by the different delineators（ F = 19.681, P = 0.000）. There was not statistically significant between