【摘要】 目的比较分析颈及上胸段食管癌不同射野数目同期加量调强放疗(SIB-IMRT)技术的剂量学参数,探讨优选方案。方法对24例食管癌患者分别设计3、5、7、9四种不同照射野数的SIB-IMRT计划。PTV-G为大体肿瘤体积(GTV)外放1cm,PTV-C为临床靶体积(CTV)外放1cm,处方剂量分别为2.15 Gy/f和2 Gy/f,28次,DT 60.2 Gy和56 Gy。通过剂量体积直方图(DVH)评估各靶区和危及器官的剂量学参数。结果 PTV-G 3、5、7、9野SIB-IMRT计划的靶区适形性指数(CI)和不均匀性指数(HI)分别为0.33、0.55、0.77、0.80和1.09、1.07、1.07、1.05,差异均有统计学意义(P<0.05);PTV-C 3、5、7、9野SIB-IMRT计划的靶区CI和HI分别为0.69、0.71、0.72、0.79和1.22、1.13、1.075、1.073,差异均有统计学意义(P<0.05)。3、5、7、9野脊髓最大剂量分别为4511.27、4288.31、4224.60和4201.43 c Gy,差异有统计学意义(P<0.05)。随着设野数目的增加,两肺的V5值增加,9野计划明显高于7野计划,分别为44.56%和32.36%(P<0.05);V20减小,9野计划与7野计划两者相似,分别为19.28%和19.65%(P>0.05)。结论 7野SIB-IMRT计划靶区剂量均匀,适形度高,对肺等重要器官的保护最佳,是颈段及上胸段食管癌SIB-IMRT治疗中优选的方案。更多还原

【Abstract】 Objective To compare the dosimetric parameters of 4 simultaneous integrated boost intensity-modulated radiotherapy( SIB-IMRT) treatment plans with different beams. Methods Four SIB-IMRT treatment plans with different beams of 3,5,7 and9 were designed for twenty-four eligible patients with cervical and upper thoracic esophageal carcinoma. PTV-G and PTV-C were defined as the GTV and CTV plus 10 mm in all directions,which were delivered simultaneously to 60. 2 Gy and 56 Gy in 28 fractions,respectively. Compared and evulated the dosimetric parameters of planning target volums and organs at risk( OARs) through the DVH diagram. Results The values of conformity index( CI) and heterogeneity index( HI) of four SIB-IMRT treatment plans with different beams of 3,5,7 and 9 were 0. 33,0. 55,0. 77,0. 80 and 1. 09,1. 07,1. 07,1. 05 in PTV-G,with significant difference( P<0. 05). The values of CI and HI of SIB-IMRT treatment plans with four different beams were 0. 69,0. 71,0. 72,0. 79 and 1. 22,1. 13,1. 075,1. 073 in PTV-C,with significant difference( P < 0. 05). The values of maximal dose of spinal cord were 4511. 27,4288. 31,4224. 60 and4201. 43 c Gy in 3,5,7,9-beams SIB-IMRT plans( P<0. 05). With increased beam numbers,the V5 increased and the V20 decreased.The 9-beams plan had significantly increased V5 and nonsignificantly decreased V20 compared to the 7-beams plan. The V5 and V20were44. 56% and 19. 28% in 9-beams plan and 32. 36% and 19. 65% in 7-beams plan. Conclusion 7-beams SIB-IMRT plan was the preferred technique in cervical and upper thoracic esophageal carcinoma with uniform target dose and high degree conformity,which could provide the best protection to the lung and other vital organs.更多还原