MOTION TRACKING SYSTEM FOR REAL TIME ADAPTIVE IMAGING AND SPECTROSCOPY

• US 20160166205A1
• Filed: 08/17/2015
• Published: 06/16/2016
• Est. Priority Date: 05/19/2006
• Status: Active Grant

• Current Assignee: Medical College of Wisconsin Incorporated, Queen's Medical Center, Research Corporation of The University of Hawaii, UWM Research Foundation
• Original Assignee: Medical College of Wisconsin Incorporated, Queen's Medical Center, Research Corporation of The University of Hawaii, UWM Research Foundation
• Inventors: Ernst, Thomas Michael, Prieto, Thomas Edmund, Armstrong, Brian Stewart Randall
• Granted Patent: US 9,867,549 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/1127 using markers
• CPC Class Codes: A61B 5/1128 using image analysis A61B5/1127 takes precedence
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7292 Prospective gating, i.e. predicting the occurrence of a physiological event for use as a synchronisation signal
• CPC Class Codes: A61B 6/0492 using markers or indicia for aiding patient positioning
• CPC Class Codes: A61B 6/547 involving tracking of position of the device or parts of the device
• CPC Class Codes: G01R 33/28 Details of apparatus provided for in groups G01R33/44 - G01R33/64
• CPC Class Codes: G01R 33/56509 due to motion, displacement or flow, e.g. gradient moment nulling G01R33/567 takes precedence
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06V 10/62 relating to a temporal dimension, e.g. time-based feature extraction; Pattern tracking
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast

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.

Claims

1. A motion tracking system for an object in the scanning volume of a scanner, comprising:

an object orientation marker attached to the object;

a detector that repeatedly detects poses of the object orientation marker;

a motion tracking computer that analyzes the poses of the object orientation marker to determine motion of the object between the repeated detections and to send tracking information to the scanner to dynamically adjust scans to compensate for motion of the object.

2. A motion tracking system for an object in the scanning volume of a scanner, comprising:

an object orientation marker attached to the object;

a camera that records repeated images;

a mirror in a fixed position with respect to the scanner positioned so that the camera records repeated reflected images of the orientation marker in the mirror;

a motion tracking computer that analyzes the repeated reflected images of the object orientation marker to determine motion of the object between the repeated images and to send tracking information to the scanner to dynamically adjust scans to compensate for motion of said object.

3. A process for compensating for patient motion in the scanning volume of a scanner that has a motion tracking system, without a specialized calibration tool, even if the motion tracking system is out of alignment with the scanner, comprising:

recording the patient motion both in scans of the patient by the scanner and in the motion tracking system, whereby the patient motion is simultaneously recorded in the coordinate frame of the scanner and in the coordinate frame of the motion tracking system;

updating the measurement coordinate transformation from the motion tracking system coordinate frame to the scanner coordinate frame to compensate for drift and other calibration inaccuracies;

transforming patient motion recorded in the coordinate frame of the motion tracking system into patient motion in the coordinate frame of the scanner using the updated measurement coordinate transformation.