肺癌放疗中的呼吸运动问题解决对策

Countermeasures to respiratory movement during lung cancer radiotherapy

目的:研究一种个体化的定位及靶区确定方法,解决肺癌放疗中准确包全肿瘤及相对减少肺损伤的矛盾问题。方法:选择30例肺癌患者,先予以体位固定,热塑体膜塑型,带膜在X线模拟定位机下观察测量呼吸时肿瘤的上下运动数据,之后带膜在CT模拟定位机下分别于平静吸气末、平静呼气末均屏气CT扫描全肺,图像资料传至Prowess工作站。由一位经验丰富的医师在吸气末图像上勾画肿瘤靶区(gross target volume,GTV)后,主要以预先测量的个体化呼吸动度外放形成内靶区(internal target volume,ITV)。其他程序按常规方法进行。结果:实验组的方法可减少ITV、计划靶区(planning target volume,PTV)的体积,并且使双肺V20减少,最终减轻放射性损伤。结论:该方法既能满意地包全呼吸运动中的肿瘤,又能减少正常组织照射受量,适用于没有4DCT的基层医院,不需要额外增加人员及设备,值得推广。

Objective To develop an individualized method for positioning and target assigning to conquer the contradiction between covering the tumor body and reducing lung injury. Methods Totally 30 lung cancer patients were selected as the subjects, who underwent postural immobilization and film remodeling. X-ray simulation localization machine was used to observe the movement of the tumor body when breathing, and then CT scanning of the lung was performed with CT simulation localization machine at end inspiration and end expiration. The images were transmitted to Prowess workstation. An experienced physician outlined GTV at the images at end inspiration, and ITV formed on the basis of the individualized breathing movement. Other programs were carried out according to conventional flow. Results The volumes of ITV and PTV could be reduced in the experimental group with V20 of both lungs decreased, and then the radiation injury could be relived. Conclusion The method can cover the tumor body with the radiation to adjacent tissues reduced, which can be used in the primary hospital without 4DCT.