ABC辅助下RapidArc放疗原发性肝癌的可行性研究

目的 通过比较3种呼吸状态下三维适形放疗(3DCRT)、传统调强放疗(IMRT)、旋转调强放疗(瓦里安公司的为RapidArc,RA)计划,探讨主动呼吸控制(ABC)辅助RA放疗原发性肝癌(HCC)的可行性。方法 选取12例HCC患者,依次完成ABC辅助下平静吸气末屏气(EIH)、平静呼气末屏气(EEH)、自由呼吸(FB)下CT模拟定位。对各呼吸状态下计划靶体积制定3DCRT、IMRT、RA (3个135°弧)计划,比较3种计划间、RA计划不同呼吸状态间的剂量学差异。结果 12例患者FB计划靶体积均大于EEH、EIH (160.8、89.5、83.1 cm³,F=6.63,P=0.004)。RA计划的适形指数和均匀性指数优于IMRT、3DCRT (0.92、0.90、0.77,F=72.55,P=0.000;0.90、0.89、0.84,F= 125.49,P=0.000)。3DCRT计划中正常肝V₂₀、V₃₀、V₄₀高于 IMRT、RA (24%、20%、19%,F=3.56,P=0.032;13%、10%、10%,F=5.74,P=0.004;8%、5%、6%,F=3.72,P=0.027)。FB RA计划的正常肝脏平均受量、V₁₀、V₂₀、V₃₀、V₄₀均高于EEH和EIH (13.46、10.25、9.48 Gy,F=3.63,P=0.038;46%、35%、32%,F=2.96,P=0.066;24%、16%、16%,F=3.69,P=0.036;13%、8%、8%,F=4.28,P=0.022;8%、5%、5%,F=2.39,P=0.108)。EEH下RA的十二指肠5 cm³体积所受剂量低于 FB 与 EIH (8.78、19.35 Gy与11.67 Gy,F=1.56,P=0.224)。3DCRT、IMRT、RA机器跳数平均为254.06、626.33、550.28 MU (F=147.35,P=0.000),治疗时间平均为135、540、130 s (F=62.83,P=0.000)。结论 ABC辅助下3个135°弧的RapidArc技术可在保证靶区准确基础上用较少治疗时间及机器跳数完成适形指数和均匀性优于IMRT计划的剂量传输,更好保护正常肝脏。

Study the feasibility in the application of RapidArc associated with active breath coordinator for radiotherapy of hepatocelluar carcinoma

Objective To study the feasibility of RapidArc (RA) associated with active breath coordinator (ABC) for hepatocelluar carcinoma (HCC) radiotherapy comparing of three-dimensional conformal radiotherapy (3DCRT),intensity modulated radiotherapy (IMRT),RA treatment plans in different breath status.Methods 12 HCC cases were selected.Three series CT scanning were completed in Free Breathing (FB),End Inspiration Hold (EIH) and End Expiration Hold (EEH) associated with ABC device.3DCRT,IMRT and RA (three 135° arcs) treatment plans were respectively designed on planning target volume (PTV) in different breath status.The dosimetric differences among 3 DCRT,IMRT and RA,among RA plans under different breath status were compared.Results The PTV in FB was larger than in EEHand EIH (160.8 cm3,89.5 cm3,83.1 cm3,F=6.63,P=0.004). The conformity index and homogeneity index of RA plans were better than IMRT and 3DCRT ( 0.92,0.90,0.77,F =72.55,P =0.000 ;0.90,0.89,0.84,F =125.49,P =0.000 ) ;the V20,V30,V40 of normal liver in 3DCRT were higher than IMRT and RA (24％,20％,19％,F=3.56,P =0.032;13％,10％,10％,F=5.74,P =0.004;8％,5％,6％,F =3.72,P =0.027).The normal liver mean dose,V10,V20,V30,V40 of RA plans in FB were higher than in EEH and EIH ( 13.46 Gy,10.25 Gy,9.48 Gy,F =3.627,P =0.038 ;46％,35％,32％,F =2.96,P=0.066;24％,16％,16％,F=3.69,P=0.036;13％,8％,8％,F=4.28,P=0.022;8％,5％,5％,F =2.39,P =0.108 ).The duodenum D5 cm3 of RA in EEH was lower than in FB and EIH (8.78 Gy,19.35 Gy and 11.67 Gy,F =1.56,P =0.224 ).The mean monitor units for 3 DCRT,IMRT,RA was 254.06 MU,626.33 MU and 550.28 MU ( F =147.35,P =0.000 ),while the mean treatment time was 135 s,540 s and 130 s respectively (F =62.83,P =0.000).Conclusions The RapidArc applying three 135°arcs with ABC in HCC radiotherapy can achieve better PTV coverage than IMRT with fewer monitor units,shorter treatment time and sparing more normal liver.