胸部肿瘤放射治疗固定与摆位误差研究

目的 利用机载千伏级锥形束CT(CBCT)研究不同定位方式对胸部肿瘤放疗的摆位误差。方法 利用CBCT扫描,来测量患者X(左右方向)、Y(前后方向)、Z(上下方向)线性摆位误差,并计算总的摆位误差。结果 各组患者在经CBCT校正后,在各个方向上的线性误差和总误差都要比校正前的误差有明显的减少。胸部热塑体罩的残留误差最小(P=0.06)。结论 经过CBCT的校准,可以明显地减少三种固定方式的摆位误差。胸膜热塑体罩由于其良好的物理限制,经CBCT校准后它的残留误差最小,摆位精度最高。

Immobilization and Setup Error Study for Thoracic Cancers Radiotherapy

Objective To study the setup errors of three immobilization methods in thoracic cancer radiotherapy with cone beam CT. Methods Setup discrepancy in R/L, S/I, and A/P directions were calculated and recorded after CBCT scan with Elekta XVI. Residue errors after correction was recorded with second CBCT scan. Total errors were also calculated. Results Setup errors were significantly reduced after CBCT correction. Group with thermoplastic frame indicated the least residue setup errors compared to the other two immobilization methods (P=0.06). Conclusion Setup correction with CBCT can reduce the setup error dramatically for thoracic cancer radiotherapy. Thermoplastic frame achieved best setup accuracy with CBCT correction.