Mr imaging for radiation therapy planning

Abstract

The invention relates to a method of MR imaging of a body () of a patient positioned in an examination volume of an MR device (). It is an object of the invention to provide a method that enables geometrically correct MR-only radiation therapy planning at minimum scan times. The method of the invention comprises the following steps: acquiring first MR imaging data representative of at least one region of the body (); analyzing said first MR imaging data to delineate at least one anatomical structure within said body region; acquiring second MR imaging data of said body region using a multi-point Dixon sequence; deriving a B0 map from said second MR imaging data; analyzing said B0 map to determine at least one low fidelity region of said B0 map; performing B0 mapping to refine the B0 map using a multi-acquisition gradient echo sequence restricted to at least one region where said delineated anatomical structure and said low fidelity region overlap completely or partially; and correcting geometrical distortions in said first and/or second MR imaging data using the refined B0 map. Moreover, the invention relates to a MR device () for carrying out the method, and to a computer program to be executed on a MR device ().