Integrating fMRI data into 3D conventional radiotherapy treatmentplanning of brain tumors

Abstract

Introduction: This study was aimed to investigate the beneficial effects of functional magnetic resonance imaging (fMRI) data in treatment planning for patients with CNS tumors in order to decrease the injury of functional regions of the brain followed by increase in life quality and survival of patients. This study pursues a novel approach in planning for the treatment of brain tumors in which using fMR imaging as a repeatable procedure, safe, and shorter scanning time functional regions of the brain are imaged and considered as organs at risk in radiation treatment planning. The present survey has been proposed for the first time in Iran and we hope that the obtained results will lead to increased quality of life. Materials and Methods: In this study, 11 patients with brain tumor were enrolled. Prior to processing and analyzing of radiation treatment planning, computed tomography (CT), conventional MR, and fMR images were acquired from the patients. fMRI data were obtained using 1.5 T Siemens scanner. Initially, structural scans were acquired an axial T1- weighted MP-RAGE sequence for the localization of activation. fMRI scans were acquired using an echo planar imaging (EPI) sequence in the same position as the structural images. Employed tasks for each patient were determined considering the tumor location and extension in conventional MR images together with our knowledge in neuroanatomy. Owing to the higher risk of radiation damage in regions near to tumor, tumor-vicinity tasks were selected. fMRI data were processed via SPM software and functional active volumes were recognized. fMRI data and conventional MR images of T1W acquired in a same position were fused with one another and sent to the planning system. In order to investigate the potential benefits of integrating fMRI information in planning system, 3D conventional plans with and without fMRI data were compared using DVH analysis. All the active volumes were contoured as functional organs at risk (FOARs) in radiation treatment planning. Results: Comparing the two plans it is expected to observe a significant dose decrease in functional regions while maintaining a similar coverage to the planning target volume and keeping structural organs at risk within accepted dose tolerance. Conclusion: Precise combination of fMRI data in radiation treatment planning is expected not only to reduce radiation injury, but also to increase the cure rate for tumors by allowing delivery of a sufficient dose without fear of adverse reactions. Therefore, not only we have missed anything, but rather have prevented the critical regions from radiation damage which can lead to increased quality of life and life expectancy of patients.