电子射野影像系统在放射治疗摆位中的临床应用

目的:利用电子射野影像系统(EPID)研究不同的热塑体膜制作方式对胸部肿瘤放射治疗时摆位准确性的影响。方法:2005-01-2005-12分别对20例胸部肿瘤患者在热塑体膜固定后进行CT定位,其中10例热塑体膜制作完成后在热塑体膜上标记3个激光灯+,并马上行CT定位,治疗时仅根据体表标志进行复位;而其余10例,在热塑体膜制作完成24 h后,于患者体表描画热塑体膜上、下界,并分别在体表和热塑体膜上描画3个激光灯+,同时用卡尺测量身体在热塑体膜上、中、下3个部位有机玻璃板边缘的距离,并做好记录。治疗复位时先根据热塑体膜上、下界与其他体表标志粗略复位,然后移走热塑体膜,测量身体左右两侧至有机玻璃板边缘的距离与记录的吻合度以及体表激光灯标记与治疗室激光灯的吻合度,然后决定是否进行微调。在完成复位后,利用EPID分别于机架角为0°和90°两个方向上进行射野验证。结果:仅根据体表标志进行复位时摆位误差较大,特别是在Y轴上。在X、Y和Z轴上的摆位误差分别为(2.86±1.17)mm、(4.10±1.22)mm和(1.57±0.87)mm;而在摆位方法改进后,在X、Y和Z轴上的摆位误差分别为(1.54±0.93)mm、(2....

Clinical research of setup optimization in radiotherapy by EPID

OBJECTIVE: To compare the difference of setup errors in radiotherapy between two different immobilization methods of thermoplastic cast used for patients with tumor in thorax by electronic portal imaging device(EPID).METHODS: From Jan.2005 to Dec.2005,20 cases with tumor in thorax were treated by 3D-radiotherapy.Two different immobilization methods were used.Ten cases were called the former group,and the landmark of body surface was pressed on the hot cast.After the body cast became cool,three laser crosses...