适形调强放射治疗校正摆位误差分析

目的分析适形调强放射治疗的摆位误差以及验证计划射野正确性。方法选取临床适形调强放射治疗患者30例,其中头颈部肿瘤12例,胸部肿瘤10例,腹部肿瘤8例。放疗前进行人工摆位后采取全锥形束CT(CBCT)图像采集并和大孔径CT平扫图像进行三维立体比较,从而得到摆位误差。结果头颈部肿瘤在左右、头脚、腹背方向的摆位误差分别是(-0.72±1.36)、(-0.61±1.44)、(-0.51±1.57)mm,外扩边界分别是2.08、2.05、2.08mm。胸腹部肿瘤左右、头脚、腹背方向的摆位误差分别是(-2.62±3.46)、(-2.41±2.94)、(-2.31±3.67)mm,外扩边界分别是6.08、5.35、5.98mm。结论头颈部摆位误差最小,胸腹部摆位误差较大。计划靶区在临床靶区外扩要根据每个患者的部位不同而定。

Analysis on position errors of CCRT

Objection To analyze the position errors at conformal radiation therapy(CCRT) and verify the accuracy of modulated radiation therapy(IMRT).Methods 30 clinical cancer patients of conformal radiation therapy(CCRT) or intensity modulated radiation therapy(IMRT) were chosen and immobilized with thermoplastic,including 12 head and neck cancer patients,10 the thorax cancer patients and 8 the belly cancer patients.Before radiotherapy,each patient accepted CBCT scan.Each CBCT image was matched with CT simulation image,the matching results were recorded and relative factors were analyzed.Res-ults Position errors of head and neck were(-0.72±1.36) mm,(-0.61±1.44) mm,(-0.51±1.57) mm and the margins were 2.08 mm,2.05 mm,2.08 mm in lateral,cranial caudal and ventral dorsal directions respectively.Position errors of the thorax cancer patients and the belly cancer patients were(-2.62±3.46) mm,(-2.41±2.94) mm,(-2.31±3.67) mm and the margins were 6.08 mm,5.35 mm,5.98 mm in lateral,cranial caudal and ventral dorsal directions respectively.Conclusion Position errors of head and neck are lowest least minimum,position errors of the thorax cancer patients and the belly cancer patients are comparatively larger.Body parts with each patient are extend from CTV outer to PTV,and the patients of radiation therapy have relocation after a long time.