Model-based respiratory motion compensation in MRgHIFU

Magnetic Resonance guided High Intensity Focused Ultrasound (MRgHIFU) is an emerging non-invasive technology for the treatment of pathological tissue. The possibility of depositing sharply localised energy deep within the body without affecting the surrounding tissue requires the exact knowledge of the target’s position. The cyclic respiratory organ motion renders targeting challenging, as the treatment focus has to be continuously adapted according to the current target’s displacement in 3D space. In this paper, a combination of a patient-specific dynamic breath model and a population-based statistical motion model is used to compensate for the respiratory induced organ motion. The application of a population based statistical motion model replaces the acquisition of a patient-specific 3D motion model, nevertheless allowing for precise motion compensation.