主动呼吸控制系统对肝脏肿瘤放疗靶区勾画设计影响的研究

Impact of ABC on Radiotherapy Target Design to Hepatic Tumor

目的观察主动呼吸控制(active breathing control,ABC)膈肌在人体纵轴方向的运动规律,探讨计划靶区(planning target volume,PTV)的设计。方法对15例肝脏肿瘤患者应用ABC,同时用Elekta Synery加速器配备的XVI系统中的Motion View功能采集连续图像150张,然后测量膈肌的运动幅度。结果15例患者经训练后均能达到ABC的要求,配合ABC可很好地控制膈肌的运动,在一次屏气的前3/4时相,膈肌在人体纵轴方向的位移幅度不超过1mm,但是在屏气的后1/4时相,膈肌在人体纵轴方向的位移幅度较大,在3.12～5.00mm,中位值为4mm。结论ABC技术可以很好地控制膈肌的运动,可减少放疗过程中肿瘤靶区的位移,进而提高3DCRT的精度。

Objective Breathing was an important factor which affected the precise target design to the liver tumors. The research was to study diaphragm movement rule in the Caudal-cranial direction with the help of active breathing control system （ABC） ,when hepatic tumors treated by radiotherapy. Methods Fifteen patients with hepatic tumor were entered into the study. With the help of ABC system, 150 series images from each patient were acquired by using the function of Motion View in X-ray Volume Imaging （XVI） of Elekta Synery. The movement amplitude and movement range of diaphragm in Caudal-cranial direction was measured and analyzed, and try to find the rule of diaphragm. Results The active breathing control system （ ABC ） procedure was well tolerated for all the 15 patients. Patients could hold their diaphragm immobilization well by using ABC system. The extent of diaphragmatic movement on Caudal-cranial direction were different during the total respiratory cycle ,which was less than lmm at the 3/4 phase of each breathholding,but varied greatly at the later 1/4 phase of the breathholding,the movement range from 3.12 -5 mm, median value 4 ram. Conclusion The extent of diaphragmatic movement can be controlled, and movement of target valume was reduced with the help of ABC system, thereby it could be more precise during Three-dimensional conformal radiotherapy. The research indicated the extent of diaphragmatic movement on Caudal-cranial direction were maximized to 5 mm at the later 1/4 phase of the breathholding. So plan target volum should be expanded 5 mm from clinical target volum on Caudal-cranial direction.