Technical Development and In Silico Implementation of SyntheticMR in Adaptive Radiation Therapy on the 1.5T MR-Linac

Motivation: SyntheticMR has not been studied on the 1.5T MR-Linac despite its potential value for treatment adaptation based on quantitative imaging. Goal(s): The goal of this study was to investigate the technical feasibility of translating SyntheticMR to the 1.5T MR-Linac for the radiation therapy workflow. Approach: SyntheticMR was scanned on phantoms and a volunteer and analyzed for geometric distortion and quantitative T1, T2, and PD vial measurements against reference values. Results: There was no significant geometric distortion. Mean bias was below 3% for T1, 13% for T2, and 3% for PD vials and the Lin's Concordance Correlation Coefficient was above 0.96 across all vials. Impact: SyntheticMR can enhance the MR-Linac workflow in the following ways: 1) multi-contrast anatomic/quantitative information in a single scan, 2) superior quantitative accuracy and spatial resolution compared to existing techniques, and 3) clinically acceptable repeatability, reproducibility, and spatial accuracy.