Dosimetric comparison of dual arc- volumetric modulated arc therapy (DA-VMAT) and seven-field inverse intensity modulated radiotherapy (IMRT) applied in the curative treatment of cervical cancer

Abstract

BACKGROUND: In cervical cancer radiotherapy, it was aimed to compare the intensity of the dose given to the tumor volume, the maximum amount of protection of critical organs and healthy tissues, the duration of treatment in monitor unit (MU) the homogeneity and conformity indices using seven field intensity modulated radiotherapy (IMRT) and dual arc-volumetric modulated arc therapy (DA-VMAT) techniques. METHODS: Fifteen patients with cervical cancer diagnosed and treated curatively, who are in stage IIB according to FIGO staging, were planned with IMRT and VMAT techniques as 50 Gy/25 fractions, and a dosimetric comparison was made in terms of target volume and organs at risk. RESULTS: In terms of critical organs while the average value of the volume percentage that received 40 Gy dose for the bladder was 57.5 % in the plans made with the IMRT technique, it was found to be 50.1% in the plans made with the VMAT technique (p<0.07). Although statistical significance could not be reached, it was observed that the protection of the VMAT technique for the intestine was relatively higher than the IMRT technique. A statistically significant difference was found in the MU produced per fraction, and the MU value of the VMAT technique was lower than the IMRT technique (p<0.001). CONCLUSION: DA-VMAT treatment technique for cervical cancer radiotherapy at low and high doses, has intestinal protection with low MU value in VMAT technique is seen as an advantage in terms of patient comfort and device performance .