ABSTRACT
Objective The objective of this study was to compare the differences between Volumetric Modulated Arc Radiotherapy(VMAT)and Fixed Field dynamic Intensity Modulated Radiotherapy(dIMRT)in dose distribution of target and organ at risk and treatment time,and to provide basis for clinical treatment.Methods Ten patients with postoperative of cervical carcinoma were selected,VMAT and seven fields dIMRT plans were designed for each patient in Monaco 5.11 planning system.We compared the differences of dose distribution of target and organ at risk,monitor units and treatment time between VMAT and 7dIMRT.Results The average dose of target for VMAT plan(46.86 Gy)was higher than that of 7dIMRT plan(46.68 Gy)(P<0.05).The percentage of the V10 and V20 of rectum and the V30 of small intestine in VMAT plan was 0.63%,3.34% and 4.14% higher than that in 7dIMRT plan,respectively(P<0.05).The conformal index(CI),homogeneity index(HI)of PTV and the other exposure dose of organ at risk for both plans were no significant differences.The average monitor units and treatment time of VMAT plan were 13.4% and 50.6% than that of 7dIMRT plan,respectively(P<0.05).Conclusion The dose distribution of VMAT plan is better or equal to that of 7dIMRT plan,but the monitor units and treatment time of VMAT plan is decreased significantly,we suggest that VMAT plan should be used for postoperative of cervical carcinoma in clinical.