MR Signature Matching (Mrsigma) for Volumetric Mri With Less Than 300ms Latency on a 1.5t MR-Linac System

The MR-Linac system offers a platform to adapt and monitor radiotherapy of tumors affected by continuous motion in real-time. However, real-time MRI technology is restricted to 2D imaging, which limits performance. MR Signature Matching (MRSIGMA) is a recently developed real-time 3D MRI technique with the MR-Linac as a target. However, MRSIGMA was tested only in a non-real-time scenario. This work develops a real-time implementation of MRSIGMA on the Elekta Unity 1.5T MR-Linac, including raw data transmission to an external computer, deep learning 4D reconstruction and correlation-based matching to demonstrate total imaging latency lower than 300ms.