胰腺占位性病变的运动规律及其影响因素初探

A preliminary study of the movement of space-occupying pancreatic lesions and its influencing factors

目的探讨胰腺占位性病变的运动规律及其影响因素，为其在精确放疗时确定PTV的安全边界提供参考价值。方法16例胰腺癌患者采用B超引导下穿刺的方法将1～2个纯金标记（fiducial）植入胰腺肿瘤体内，并在模拟定位机下对标记的运动幅度进行测量，得出其在患者身体左右（z轴）、前后（Y轴）、头脚（z轴）方向的移动数据。用多元线性回归模型分析影响因素。结果测量结果显示16例患者在z轴方向的移动距离为0．1～0．3cm[（0．16±0．06）cm]，2轴方向为0．5～1．6cm[（0．88±0．24）cm]，Y轴方向为0．1～0．4cm[（0．25±0．12）cm]。其移动距离与患者年龄、身高、体重、肿瘤位置和大小无关。结论胰腺占位性病变的移动主要受呼吸运动影响，且在z轴方向的移动距离最大，在确定PTV安全边界时应主要考虑其在：轴方向的移动。

Objective To investigate the movement and its influencing factors of the space-occupying pancreatic lesions and provide a reference for the safe margin between CTV and PTV in accurate radiotherapy. Methods Gold fiducials were implanted into the lesions of 16 pancreatic carcinoma patients by percutaneous punctures under B-uhrasonographic guidance. The movements of these markers were measured under the X-ray simulator system in the x, y and z axial directions, respectively. The relevant influencing factors were analyzed. Results The motion amplitudes of pancreatic lesions were 0.1 - 0.3 （ mean 0.16±0.06） cm,0. 1 -0.4 （mean 0.25±0. 12） cm and 0.5 - 1.6 （mean 0. 88±0.24） em in the x,y and z axial directions, respectively. The movements were not associated with the height, weight, age, tumor location or tumor size. Conclusions The motion of the space-occupying pancreatic lesions is mainly influenced by the respiration, especially with the maximal amplitude in the z axial direction. Therefore, the motion in the z axial direction should be given more consideration when determining the PTV margin.