Motion tracking during non-invasive therapy

A system for tracking at least one moving anatomical object during a treatment sequence, the system comprising:

• (a) an imaging apparatus, operable in conjunction with a treatment apparatus, for (i) acquiring, prior to the treatment sequence, a series of reference images of an anatomical region comprising the object during motion thereof, each reference image corresponding to a different stage of the motion, and (ii) acquiring treatment images of the anatomical region during the treatment sequence, the treatment images containing less information than the reference images;
• (b) means for acquiring complementary information indicative of the stage of the motion during acquisition of the treatment images;
• and
• (b) a computation unit configured to (i) receive complementary information, (ii) process the reference images to determine, for each reference image, a location associated with the object, (iii) correlate at least one of the treatment image to a corresponding reference image based on similarity therebetween and the received complementary information, and (iii) track the object in the at least one treatment image based at least in part on the location associated with the object in the corresponding reference image;
• wherein the reference images and treatment images are MRI images.

A method for tracking a moving anatomical object during treatment, the method comprising:

• (a) prior to the treatment,
• (i) acquiring a series of reference images of an anatomical region comprising the anatomical object during motion thereof, each reference image corresponding to a different stage of the motion;
• and
• (ii) processing the images to determine, for each image, a location associated with the object;
• and
• (b) during the treatment,
• (i) performing a scanning sequence to acquire image data associated with the anatomical object, the scanning sequence comprising a plurality of scanning lines;
• wherein the reference images are MRI images, and treatment image data is MRI data;
• (ii) acquiring complementary information associated with the anatomical object during acquisition of the treatment image data;
• (iii) computing similarity between the acquired treatment image data and the reference images to identify at least one matching reference image;
• wherein the treatment image data contains less information than the reference images;
• (iv) determining whether a number of the matching reference images is below a threshold;
• and
• if so, selecting one of the matching reference images based on the similarity and the complementary information, and inferring a location of the anatomical object from the location associated with the anatomical object in the selected reference image;
• if not, based on the pre-determined scanning sequence, performing the scanning sequence in a next scanning line to acquire the image data of the anatomical object and repeating steps (ii), (iii) and (iv).