Rapid 4D-MRI reconstruction using a deep radial convolutional neural network: Dracula

Highlights: • Deep learning accelerates 4D-MRI recon for online adaptive MR-guided radiotherapy. • First reconstruction of high resolution whole thorax 4D-MRI for 16 phases in 28 s. • First use of dCNNs for midposition reconstruction from undersampled 4D-MRI in 28 s. • Excellent agreement between deep learning-based tumour midposition and reference. 4D and midposition MRI could inform plan adaptation in lung and abdominal MR-guided radiotherapy. We present deep learning-based solutions to overcome long 4D-MRI reconstruction times while maintaining high image quality and short scan times.