Systems, devices, and methods for tracking and compensating for patient motion during a medical imaging scan

Abstract

A motion compensation system for tracking and compensating for patient motion during a medical imaging scan comprises an optical marker comprising an optically visible pattern and a mounting portion; a first optical detector positioned to digitally image the optically visible pattern along a first line of sight; a second optical detector positioned to digitally image the optically visible pattern along a second line of sight; a tracking engine configured to determine a pose of the object in six degrees of freedom by analyzing images from the first and second optical detectors; and a controller interface configured to generate tracking information based on the pose and to electronically transmit the tracking information to a scanner controller to enable compensation within a medical imaging scanner for object motion.

1 .- 20 . (canceled) 
     
     
         21 . A motion compensation system for tracking and compensating for subject motion during a medical imaging scan, the motion compensation system comprising:
 an optical marker comprising an optically visible pattern, the optical marker configured to be attached to a subject being tracked, the optically visibly pattern comprising a plurality of reference point locators, wherein a centroid of each of the plurality of reference point locators defines a reference point;   a first optical detector configured to generate a first digital image of the optically visible pattern;   a second optical detector configured to generate a second digital image of the optically visible pattern;   one or more computer readable storage devices configured to store a plurality of computer executable instructions; and   one or more computer processors in communication with the one or more computer readable storage devices and configured to execute the plurality of computer executable instructions in order to cause the system to:
 determine a pose of the subject in six degrees of freedom by analyzing the first digital image and the second digital image; and 
 generate tracking information based on the determined pose and electronically transmit the tracking information to a scanner controller to enable compensation within a medical imaging scanner for subject motion. 
   
     
     
         22 . The motion compensation system of  claim 21 , wherein the first optical detector and the second optical detector are attached to the medical imaging scanner. 
     
     
         23 . The motion compensation system of  claim 21 , wherein the first optical detector and the second optical detector are attached to a head coil to be used in conjunction with the medical imaging scanner. 
     
     
         24 . The motion compensation system of  claim 21 , wherein the medical imaging scanner comprises a magnetic resonance scanner. 
     
     
         25 . The motion compensation system of  claim 21 , wherein the optically visible pattern is located on a single unitary structure. 
     
     
         26 . The motion compensation system of  claim 21 , wherein the optically visible pattern is distributed among at least two non-connected structures. 
     
     
         27 . The motion compensation system of  claim 21 , wherein the first optical detector is positioned to digitally image the optically visible pattern along a first line of sight, and wherein the second optical detector is positioned to digitally image the optically visible pattern along a second line of sight. 
     
     
         28 . The motion compensation system of  claim 27 , wherein the first and second lines of sight are separated by 90 degrees. 
     
     
         29 . The motion compensation system of  claim 27 , wherein the first line of sight is offset angularly by a first angle from a normal to the optically visible pattern and the second line of sight is offset angularly by a second angle from the normal to the optically visible pattern, wherein a magnitude of the first angle is the same as a magnitude of the second angle. 
     
     
         30 . A motion compensation system for tracking and compensating for subject motion during a medical imaging scan, the motion compensation system comprising:
 an optical marker comprising an optically visible pattern, the optical marker configured to be attached to a subject being tracked;   a first optical detector configured to generate a first digital image of the optically visible pattern;   a second optical detector configured to generate a second digital image of the optically visible pattern;   one or more computer readable storage devices configured to store a plurality of computer executable instructions; and   one or more computer processors in communication with the one or more computer readable storage devices and configured to execute the plurality of computer executable instructions in order to cause the system to:
 determine a pose of the subject in six degrees of freedom by analyzing the first digital image and the second digital image, wherein analyzing the first digital image and the second digital image comprises:
 defining a region of interest for each of the digital images, the region of interest comprising a portion of the digital image within which the optically visible pattern is anticipated to appear; and 
 analyzing only the region of interest in determining the pose of the subject; and 
 
 generate tracking information based on the determined pose and electronically transmit the tracking information to a scanner controller to enable compensation within a medical imaging scanner for subject motion. 
   
     
     
         31 . The motion compensation system of  claim 30 , wherein the system is further caused to automatically move the region of interest based on anticipated future motion of the subject being tracked. 
     
     
         32 . The motion compensation system of  claim 30 , wherein the first optical detector is positioned to digitally image the optically visible pattern along a first line of sight, and wherein the second optical detector is positioned to digitally image the optically visible pattern along a second line of sight. 
     
     
         33 . The motion compensation system of  claim 32 , wherein the first and second lines of sight are separated by 90 degrees. 
     
     
         34 . The motion compensation system of  claim 32 , wherein the first line of sight is offset angularly by a first angle from a normal to the optically visible pattern and the second line of sight is offset angularly by a second angle from the normal to the optically visible pattern, wherein a magnitude of the first angle is the same as a magnitude of the second angle. 
     
     
         35 . A motion compensation system for tracking and compensating for subject motion during a medical imaging scan, the motion compensation system comprising:
 an optical marker comprising an optically visible pattern, the optical marker configured to be attached to a subject being tracked, the optically visible pattern comprising one or more reference points;   a first optical detector configured to generate a first digital image of the optically visible pattern;   a second optical detector configured to generate a second digital image of the optically visible pattern;   one or more computer readable storage devices configured to store a plurality of computer executable instructions; and   one or more computer processors in communication with the one or more computer readable storage devices and configured to execute the plurality of computer executable instructions in order to cause the system to:
 determine a pose of the subject in six degrees of freedom by analyzing the first digital image and the second digital image, wherein analyzing the first digital image and the second digital image comprises:
 determining one or more positions of the one or more reference points; 
 calculating one or more baseline attributes based on the determined one or more positions of the one or more reference points; and 
 iteratively estimating a pose of the subject being tracked until an amount of error is within a threshold amount; and 
 
 generate tracking information based on the determined pose and electronically transmit the tracking information to a scanner controller to enable compensation within a medical imaging scanner for subject motion. 
   
     
     
         36 . The system of  claim 35 , wherein the amount of error is determined by comparing the one or more baseline attributes to one or more comparison attributes, the one or more comparison attributes calculated by assuming the subject is in an estimated pose. 
     
     
         37 . The motion compensation system of  claim 35 , wherein the first optical detector is positioned to digitally image the optically visible pattern along a first line of sight, and wherein the second optical detector is positioned to digitally image the optically visible pattern along a second line of sight. 
     
     
         38 . The motion compensation system of  claim 37 , wherein the first and second lines of sight are separated by 90 degrees. 
     
     
         39 . The motion compensation system of  claim 37 , wherein the first line of sight is offset angularly by a first angle from a normal to the optically visible pattern and the second line of sight is offset angularly by a second angle from the normal to the optically visible pattern, wherein a magnitude of the first angle is the same as a magnitude of the second angle. 
     
     
         40 . The motion compensation system of  claim 35 , wherein the system is caused to repeatedly determine the pose of the subject at a rate of at least 100 Hz.