Magnetic resonance projection imaging

A computer-implemented method to control radiation therapy delivery to a subject using projection imaging, the method comprising:

• receiving reference imaging information;
• generating a two-dimensional (2D) projection image using imaging information obtained via nuclear magnetic resonance (MR) projection imaging, the 2D projection image corresponding to a specified projection direction, the specified projection direction including a path traversing at least a portion of an imaging subject;
• determining a change between the generated 2D projection image and the reference imaging information;
• and
• generating an updated therapy protocol for delivery of a radiation therapy at least in part using the determined change between the obtained 2D projection image and the reference imaging information;
• wherein the reference image comprises an image extracted from a selected portion of 4D imaging information, the 4D imaging information assembled from earlier-acquired imaging information;
• and
• wherein a selected portion of the 4D imaging information comprises a specified portion of a physiologic cycle.

A radiation therapy treatment system, comprising:

• a therapy controller system comprising an imaging input, the imaging input configured to receive reference imaging information, the therapy controller system configured to:
• generate a two-dimensional (2D) projection image using imaging information obtained via nuclear magnetic resonance (MR) projection imaging, the 2D projection image corresponding to a specified projection direction, the specified projection direction including a path traversing at least a portion of an imaging subject;
• determine a change between the generated 2D projection image and the reference imaging information;
• and
• control delivery of the radiation therapy using the determined change between the obtained 2D projection image and the reference imaging information.