Comparison of dosimetry between RapidArc and 5F-IMRT in treatment of locally advanced pancreatic carcinoma / 吉林大学学报(医学版)

ABSTRACT

Objective:To explore the dose distribution characteristics between RapidArc and five-field intensity modulated radiotherapy(5F-IMRT) plans in the treatment of locally advanced pancreatic carcinoma,and to provide reference for selecting the appropriate radiation technique in clinic.Methods:Ten patients with locally advanced pancreatic carcinoma were selected.The patients were scanned by simulation CT, and the targets and organs at risk were contoured. RapidArc plan and 5F-IMRT plan were designed respectively.The treatment time and the differences of dose distribution in the targets and organs at risk of RapidArc and 5F-IMRT plans were compared.Results:The conformal index (CI) of RapidArc plan was superior than that of 5F-IMRT plan(P=0.01).The homogeneity index (HI) of targets were similar between two plans (P>0.05).RapidArc plan decreased the maximum dose (Dmax) of the spinal cord(P=0.005);RapidArc plan decreased the mean dose(Dmean) of stomach(P=0.019);5F-IMRT plan decreased the V20 of kidney(P=0.043);RapidArc plan decreased the mean dose(Dmean) of small intestine(P=0.011).The small intestine V10 and V20 of RapidArc plan were lower than those of 5F-IMRT plan(P=0.015,P=0.14);the monitor unit (MU) of RapidArc plan was significantly lower than that of 5F-IMRT plan,with a 18% reduction from the MU level of the latter one,and the treatment time was reduced by 70.3%.RapidArc plan had the smaller doses at liver and kidney compared with 5F-IM RT plan.Conclusion:For the patients with locally advanced pancreatic carcinoma,RapidArc plan has higher CI. RapidArc plan shows the advantages in the protection of organs.Compared with 5F-IMRT,RapidArc plan has less treatment time and significantly improves the curative efficiency.In clinic, the RapidArc plan is recommended.