Respiratory Motion Detection and Reconstruction Using CAPTURE and Deep Learning for a 0.35T MRI-LINAC System: An Initial Study

Magnetic Resonance Imaging Guided Linear Accelerator (MRI-LINAC) combines an MRI system with a linear accelerator radiotherapy system to treat patients. The MRI-LINAC uses MR to track organ or lesion motion and gates the radiation beam accordingly. In this study, we demonstrate the combination of a T1-weighted self-navigated respiratory motion detection method (CAPTURE) with a deep learning 4D reconstruction (Phase2Phase, P2P) method to derive the 3D deformable respiratory motion field from data acquired on a 0.35 T ViewRay MRI-LINAC system. This initial study demonstrated promising results despite the low SNR at this field strength.