Rapid MRI 4D Image Guidance for Motion Management in Lung Cancer Radiotherapy

Amit Sawant¹, Sarang Joshi²

This work investigates real-time MRI for image-guided radiation therapy of moving and deforming lung tumors. We hypothesize that, for the task of lung radiotherapy guidance, MRI acquisition speed can be increased significantly at the cost of loss in image SNR. We present results for scans acquired from two lung cancer patients on a 1.5T scanner under free-breathing conditions and without externally administered contrast using a balanced SSFP sequence. Image acquisition times of ~6.5 frames/s were achieved for 2D time series and ~0.8 volumes/s for a 3D time series. In each case, the tumor and structures of interest were clearly delineated.