Comparison Of Dosimetry In Primary Liver Cancer Between Simplify Intensity-modulated Radiotherapy And Votumetrically Modulated Arc Therapy

Objective: To evaluate the different dosimetric results of sIMRT andRapidArc for primary liver cancer, and provide a reference for selecting the bestradiotherapy technique in clinic.Materials and methods: Ten patients with primary liver cancer wereenrolled into this study. sIMRT and RapidArc plans were designed for eachpatient. The prescribed dose was50Gy in25fractions. Plans were compared interms of conformity index, homogeneity index of target volume and receivingdose to critical organs by analysis of dose-volume histogram.Results:(1) Compared with sIMRT plan, the maximum and mean dose ofPGTV was reduced by0.93Gy and0.46Gy while the minimun dose of PGTVwas elevated by3.38Gy. The CI was0.84±0.02and0.92±0.02(t=8.00, P<0.05),and HI was1.07±0.01and1.04±0.01(t=3.50, P <0.05) for sIMRT and RapidArc,respectively.(2) The mean dose and V30of the normal liver of RapidArc were allsignificantly lower than those of sIMRT (P<0.05); V20of liver and kidney, themean dose of kidney and the maximum dose of spinal cord of RapidArc werelower than those of sIMRT, while sIMRT plan reduced V10of liver and the mean dose of stomach, but all of the differences were statistically significant.(3)Compared with sIMRT, RapidArc took significantly less treatment time andmonitor units.Conclusion: Both RapidArc and sIMRT techniques can satisfy therequirement of clinic dosimetry. RapidArc has better conformity index andHomogeneity index. It is in advantage of liver protection significantly. What’smore, RapidArc takes less treatment time and monitor units.