Comprehensive and Comparative Dosimetric Characterization of VMAT and IMRT in Brain Cancer Treatment Planning: Target Coverage, OAR Sparing, Monitor Units, Dose Distribution, Low-Dose Volumes, and Delivery Efficiency

Abstract

Purpose: A detailed dosimetric comparison is conducted between VMAT and IMRT modalities for brain tumor treatment plans concerning prescription doses of 60, 66, and 70 Gy.

Material and Methods: A total number of forty-three brain tumor patients were selected by means of a retrospective study in the Radiotherapy Department at Baquba Teaching Hospital. Two different treatment plans were made for each patient; one by VMAT, and another by IMRT, for a total of 86 treatment plans. All treatment plans were designed under the same conditions of CT scan images, target contouring, and organ-at-risk constraints.

Results: Overall high PTV coverage was achieved with both techniques and no significant difference was observed in D95 D98 D50 or D2 HI and CI were also comparable, however, higher mean values were obtained for V5 V10 and V20 for the IMRT and a lower number of monitor units were used for treatment delivery in VMAT.

Conclusion: VMAT and IMRT were comparable in terms of target coverage and normal tissue protection, but VMAT needed fewer monitor units and had a significantly lower V20 with numerically lower V5 and V10 although these were not statistically significant.