Comparative study of coplanar and non-coplanar intensity-modulated radiotherapy in advanced lung cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective To study the dosimetry and safety of the non-coplanar IMRT plan for advanced lung cancer.Methods The two groups IMRT plans were designed with coplanar (5,7F) and non-coplanar field (5,7F-n) for patients.To compare the dosimetry of two groups and perform 4 patients F7-n IMRT plan.Results With the increase of the fields in each group PTV's CI were improved (all P =0.000),especially the 7F-n plan PTV's Dmean,Dmax,V95％ and HI also were improved (P=0.001,0.001,0.009,0.000) ; in the coplanar group each lung' s V5 increased (P =0.000,0.002,0.000) and whole lung's Dmean increased (P =0.000),but non-coplanar group whole lung's and contralateral lung's V5 reduce (P =0.001,0.005).Between the groups,7F-n plan PTV's indicators were all improved to compared with 5F plan (all P =0.000),and each lung's V20 reduced (all P =0.000),and whole lung's Dmean,V30,contralateral lung' s V5 reduced (P =0.000,0.001,0.000),and spinal cord' s Dmax also reduced (P =0.033),but ipsilateral lung's V5 and heart's Dmean increased (P =0.000,0.003);with compared to 7F plan,the 7F-n's ipsilateral lung's V5 and heart's Dmean also increased (P =0.000,0.048),but whole lung' s and contralateral lung's V5 decreased (all P =0.000).Four patients were performed successfully non-coplanar IMRT treatment,no collision occurred.Conclusions 7 fields non-coplanar IMRT plan not only improve the dose distribution of PTV,but also effectively control the volume of low dose lung increase,lung V20 and Dmean reduce too.Thus recommended to use this design in patients with advanced lung cancer for radiotherapy