Feasibility of using MRI alone for 3D radiation treatment planning in brain tumors

Objective: The aim of this study was to establish whether radiation treatment planning using MRI alone could replace CT-based planning for brain tumors while retaining the dosimetric accuracy. This would help to provide a single imaging modality for both target delineation as well as treatment planning, thus saving time and resources. Methods: Twenty-five patients with brain tumors were scanned on a spiral CT scanner and 1.5 T MRI scanner. Three treatment plans were generated for all patients. The first plan was generated using the CT scan images with inhomogeneity correction (CT + IC); the second plan used the CT scan without inhomogeneity correction (CT - IC) and the third plan was generated using the MRI scan (MRI alone). Results: The maximum distortion in the MRI phantom study was less than 1 mm. There were no statistically significant differences in any of the target coverage parameters analysed in this study. Similarly, the maximum antero-posterior and lateral dimensions for the CT-based and MRI-based planning did not show any statistical difference. Conclusion: MRI-based treatment planning for brain lesions is feasible and gives equivalent dosimetric results compared to CT-based treatment planning.