【摘要】 目的　本实验为解决位于胸腔肿瘤行立体定向放射治疗时随呼吸动度的影响。方法　对 48例肺癌患者肿瘤动度的实际测量 ,得出肺不同部位肿瘤的动度数据 ;通过模拟呼吸动度下肿瘤体积变化和CT扫描方式的研究 ,将不同体积的小球分别在不同CT扫描时间下进行体积测量分析。结果　⑴位于上肺的肿瘤在X、Y方向动度很小 ,为 (0 .2 0± 0 .0 6 )、(0 .2 0± 0 .11)cm ;下肺X、Y方向动度由于受心脏和大动脉搏动影响 ,稍大于上肺为 (0 .31± 0 .10 )、(0 .36± 0 .10 )cm ;但不论肿瘤位于肺的什么部位 ,对Z轴方向影响最大 ;尤以下肺更显著 ,为 (0 .90± 0 .45 )～ (0 .93± 0 .46 )cm ,这主要受膈肌影响。⑵每一层组织CT扫描时间大于或等于一个呼吸周期的话 ,肿瘤信息不会丢失 ,而且三维重建图像包括了各方向的动度 ;如采用螺旋CT快速扫描则三维重建图像不能包括肿瘤的全部动度。结论　肺部肿瘤呼吸动度影响主要是Z轴方向。如果定位时CT扫描 (每一层组织 )所需时间与每个呼吸周期时间一致的话 ,重建肿瘤轮廓完全包括了动度的影响 ,确定大肿瘤体积 (GTV)根本不需加安全边界。而用扫描时间小于呼吸周期的CT(如螺旋CT)则治疗计划重建的三维影像不能反映出肿瘤的全部动度范围更多还原

【Abstract】 Objective To study the range of movement of pulmonary lesion and diaphragm in stereotactic radiotherapy for lung cancers. Methods We measured the range of movement in 48 lung cancer patients. The movement at different locations of the lung varied. The change in tumor volume from the reconstructed three dimensional (3D) images during respiration as measured by a respiratory simulator was observed. Results The movement was smaller in upper parts of lung in the X and Y directions (0.2±0.06)～(0.20±0.11 )?cm. The movement of the lower field of lung was larger than that of the upper fields (0.31±0.10)～(0.36±0.10)?cm. This is due to the heart and aortic pulsation. However, the movement was the largest in the Z direction (0.9± 0.45 )～(0.93±0.46)?cm. Moreover, if the time of computed tomography (CT) scan for each slice of lung tissue was equal to or longer than the interval of a breathing cycle, the tumor information was not lost. The reconstructed 3D images involved all the movements. The size of reconstructed 3D images changed inversely with the breathing movement. Conclusions The affection of breathing movement in lung cancer is chiefly in the Z direction. If the time of CT scan is equal to or longer than the interval of a breathing cycle, the reconstructed 3D images will encompass all the information of the tumor and its movement, showing the gross tumor volume (GTV) which does not need any safety margin. If the time of CT is shorter than the breathing cycle like the spiral CT, the reconstructed 3D image can not show the range of tumor movement.更多还原