Motion tracking system for real time adaptive imaging and spectroscopy

Abstract

This invention relates to a system that adaptively compensates for subject motion in real-time in an imaging system. An object orientation marker (30), preferably a retro-grate reflector (RGR), is placed on the head or other body organ of interest of a patient (P) during a scan, such as an MRI scan. The marker (30) makes it possible to measure the six degrees of freedom (x, y, and z-translations, and pitch, yaw, and roll), or “pose”, required to track motion of the organ of interest. A detector, preferably a camera (40), observes the marker (30) and continuously extracts its pose. The pose from the camera (40) is sent to the scanner (120) via an RGR processing computer (50) and a scanner control and processing computer (100), allowing for continuous correction of scan planes and position (in real-time) for motion of the patient (P). This invention also provides for internal calibration and for co-registration over time of the scanner's and tracking system's reference frames to compensate for drift and other inaccuracies that may arise over time.

1 .- 3 . (canceled) 
     
     
         4 . A motion tracking system for tracking motion of an object during a medical imaging scan, the system comprising:
 a detector configured to image one or more optical landmarks on the object during the medical imaging scan, the detector configured to be positioned within a medical imaging scanner;   a tracking system configured to analyze images generated by the detector to determine changes in one or more positions or orientations of the one or more optical landmarks;   the tracking system further configured to generate tracking data for use by the medical imaging scanner to dynamically compensate for changes in the one or more positions or orientations of the one or more optical landmarks during the medical imaging scan,   wherein the tracking system comprises a computer processor and an electronic storage medium.   
     
     
         5 . The motion tracking system of  claim 4 , wherein the tracking system is further configured to predict changes in the one or more positions or orientations of the one or more optical landmarks by analyzing one or more previous changes in the one or more positions or orientations of the one or more optical landmarks. 
     
     
         6 . The motion tracking system of  claim 4 , wherein the detector comprises a camera. 
     
     
         7 . The motion tracking system of  claim 4 , wherein the tracking system is configured to determine changes in the one or more positions or orientations of the one or more optical landmarks in six degrees of freedom. 
     
     
         8 . The motion tracking system of  claim 4 , wherein the one or more optical landmarks comprises an optical marker. 
     
     
         9 . The motion tracking system of  claim 8 , wherein the one or more optical landmarks comprises an RGR marker. 
     
     
         10 . The motion tracking system of  claim 4 , wherein the one or more optical landmarks is located on a surface of the object. 
     
     
         11 . The motion tracking system of  claim 4 , wherein the medical imaging scanner comprises a computer tomography (CT) scanner, a magnetic resonance (MR) scanner, Positron Emission Tomography (PET) scanner, or a Single Photon Emission Computerized Tomography (SPECT) scanner. 
     
     
         12 . The motion tracking system of  claim 4 , wherein the generated tracking data is configured to be used to dynamically adjust one or more scan parameters during the medical imaging scan. 
     
     
         13 . The motion tracking system of  claim 12 , wherein the one or more scan parameters comprises a MR pulse sequence. 
     
     
         14 . The motion tracking system of  claim 4 , wherein the detector is shielded to avoid interference with the medical imaging scanner. 
     
     
         15 . The motion tracking system of  claim 4 , wherein the medical imaging scanner comprises an MR scanner, and wherein the detector is configured to be placed inside a magnet of the MR scanner. 
     
     
         16 . The motion tracking system of  claim 4 , further comprising at least one mirror configured to provide an indirect line of sight between the one or more optical landmarks and the detector. 
     
     
         17 . The motion tracking system of  claim 4 , wherein the tracking system is further configured to transform the generated tracking data into coordinates usable by the medical imaging scanner. 
     
     
         18 . A computer-implemented method of tracking motion of an object during a medical imaging scan, the method comprising:
 generating, by a detector, images of one or more landmarks on the object during the medical imaging scan, the detector configured to be positioned within a medical imaging scanner;   analyzing, by a tracking system, the images of the one or more landmarks generated by the detector to determine changes in one or more positions or orientations of the one or more landmarks;   generating, by the tracking system, tracking data for use by the medical imaging scanner to dynamically compensate for changes in the one or more positions or orientations of the one or more landmarks during the medical imaging scan,   wherein the tracking system comprises a computer processor and an electronic storage medium.   
     
     
         19 . The method of  claim 18 , further comprising predicting, by the tracking system, changes in the one or more positions or orientations of the one or more landmarks by analyzing one or more previous changes in the one or more positions or orientations of the one or more landmarks. 
     
     
         20 . The method of  claim 18 , wherein the changes in the one or more positions or orientations of the one or more landmarks are determined by the tracking system in six degrees of freedom. 
     
     
         21 . The method of  claim 18 , wherein the one or more landmarks comprises an optical marker. 
     
     
         22 . The method of  claim 18 , wherein the one or more landmarks is located on a surface of the object. 
     
     
         23 . The method of  claim 18 , wherein the generated tracking data is configured to be used to dynamically adjust one or more scan parameters during the medical imaging scan.