Investigation and comparison of coplanar versus noncoplanar intensity-modulated radiation therapy (imrt) techniques in glioblastoma multiforme tumors

Abstract

Background: This study aimed to make a comparison among 4 coplanar and noncoplanar intensity-modulated radiation therapy (IMRT) techniques in glioblastoma multiforme (GBM) tumors, to achieve an optimal treatment technique considering the absorbed doses of organs at risk. Methods: Treatment planning and contouring were performed on 20 patients with glioblastoma multiforme tumors in 2 phases based on Radiation Therapy Oncology Group (RTOG) protocol. Four coplanar and noncoplanar intensity-modulated radiation therapy techniques at 6 and 15 MV energy levels were compared. Finally, comparing the conformity and homogeneity indices, and maximum and mean doses (using dose volume histogram), the optimal treatment technique was proposed. Findings: The absorbed doses of critical organs in the cases of noncoplanar techniques reduced drastically compared with the cases of coplanar techniques. Increase in energy levels in noncoplanar techniques did not impose any significant changes. Conclusion: The absorbed doses of all critical organs in noncoplanar technique with 6 MV energy level reduced significantly. Besides, in this technique, there was no neutron contamination, because of the employment of 6 MV energy. © 2018, Isfahan University of Medical Sciences(IUMS). All rights reserved.