Motion tracking system for real time adaptive imaging and spectroscopy
This invention relates to a system that adaptively compensates for subject motion in real-time in an imaging system. An object orientation marker, preferably a retro-grate reflector (RGR), is placed on an organ of interest of a patient during a scan, such as an MRI scan. The marker allows measuring the six degrees of freedom or “pose” required to track motion of the organ of interest. A detector, preferably a camera, observes the marker and continuously extracts its pose. The pose from the camera is sent to the scanner via an RGR processing computer and a scanner control and processing computer, allowing for continuous correction of scan planes and position (in real-time) for motion of the patient. 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. A motion tracking system for an object in an magnetic resonance imaging scanner, the system comprising:
an object orientation marker configured to be coupled to the object;
a magnetic resonance imaging scanner configured to scan the object;
a detector configured to periodically image the object orientation marker, the detector configured to be positioned within the magnetic resonance imaging scanner; and
a tracking system configured to analyze images generated by the detector to determine changes in position of the object orientation marker, and to generate tracking data for use by the magnetic resonance imaging scanner to dynamically adjust scans to compensate for the changes in position of the object orientation marker;
wherein the tracking system comprises a computer processor and an electronic memory.
2. The motion tracking system of claim 1 , further comprising a first mirror configured to split a sight line of the detector into a first path and a second path;
wherein the first path is directed directly at the object orientation marker;
wherein the second path is directed toward a second mirror; and
wherein the second mirror is configured to deflect the second path toward the object orientation marker.
3. The motion tracking system of claim 2 , wherein the first mirror is a semi-transparent mirror configured to partially deflect the sight line of the detector onto the second path and to allow a non-deflected portion of the sight to pass through the first mirror and onto the first path.
4. The motion tracking system of claim 2 , wherein the first mirror is a fully-reflective mirror configured to be positioned in a portion of the sight line of the detector in order to deflect only a fractional part of the sight line onto the second path.
5. The motion tracking system of claim 2 , wherein the first mirror is configured to be coupled to a second object orientation marker.
6. The motion tracking system of claim 2 , wherein the second mirror is configured to be coupled to a third object orientation marker.
7. The motion tracking system of claim 5 , wherein the tracking system is configured to analyze images generated by the detector to determine changes in position of the second object orientation marker, and to automatically calibrate the tracking system.
8. The motion tracking system of claim 6 , wherein the tracking system is configured to analyze images generated by the detector to determine changes in position of the third object orientation marker, and to generate tracking data to automatically calibrate the tracking system.
9. The motion tracking system of claim 1 , wherein the detector is a camera.
10. A motion tracking system for an object in an magnetic resonance imaging scanner, the system comprising:
an object orientation marker configured to be coupled to the object;
a detector configured to periodically image the object orientation marker, the detector configured to be positioned within the magnetic resonance imaging scanner; and
a tracking system configured to analyze images generated by the detector to determine changes in position of the object orientation marker, and to generate tracking data for use by the magnetic resonance imaging scanner to dynamically adjust scans to compensate for the changes in position of the object orientation marker;
wherein the tracking system comprises a computer processor and an electronic memory.
11. The motion tracking system of claim 10 , further comprising a first mirror configured to split a sight line of the detector into a first path and a second path;
wherein the first path is directed directly at the object orientation marker;
wherein the second path is directed toward a second mirror; and
wherein the second mirror is configured to deflect the second path toward the object orientation marker.
12. The motion tracking system of claim 11 , wherein the first mirror is a semi-transparent mirror configured to partially deflect the sight line of the detector onto the second path and to allow a non-deflected portion of the sight to pass through the first mirror and onto the first path.
13. The motion tracking system of claim 11 , wherein the first mirror is a fully-reflective mirror configured to be positioned in a portion of the sight line of the detector in order to deflect only a fractional part of the sight line onto the second path.
14. The motion tracking system of claim 11 , wherein the first mirror is configured to be coupled to a second object orientation marker.
15. The motion tracking system of claim 11 , wherein the second mirror is configured to be coupled to a third object orientation marker.
16. The motion tracking system of claim 14 , wherein the tracking system is configured to analyze images generated by the detector to determine changes in position of the second object orientation marker, and to automatically calibrate the tracking system.
17. The motion tracking system of claim 15 , wherein the tracking system is configured to analyze images generated by the detector to determine changes in position of the third object orientation marker, and to generate tracking data to automatically calibrate the tracking system.
18. The motion tracking system of claim 10 , wherein the detector is a camera.