Automatic ultrasonic localization of targets implanted in a portion of the anatomy
First Claim
1. A method for automatically locating a position of a first object in a physical space, comprising steps of:
- attaching a transducer to a coordinate space digitizer having a defined coordinate system in said physical space;
pulsing said transducer while translating it along a surface of interest near said first object;
receiving echoes from said pulsed transducer arising from a difference in an acoustic impedance of a first portion of the first object and an acoustic impedance of a material located near said first portion of the first object; and
determining automatically a coordinate position in said defined coordinate system of said first object in response to said received echoes and a position and orientation of said transducer.
3 Assignments
0 Petitions
Accused Products
Abstract
In a coordinate system defined by a coordinate space digitizer, the location of an implanted symmetric object may automatically be determined based on differences between the characteristic acoustic impedances of at least a portion of an implanted object and one or more materials surrounding that object. An A-mode ultrasound transducer may be attached to a coordinate space digitizer or pointing device such that an attached computer tracks the position and orientation of the ultrasound transducer. The reflected radio-frequency (rf) ultrasound signals may automatically be analyzed along with the transducer position and orientation corresponding to each received rf signal to detect the position of the implanted object. The time delay between received ultrasound echoes is used to compute the depth of the object from the transducer. This allows for an accurate determination of the three-dimensional coordinates of the implanted object.
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Citations
80 Claims
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1. A method for automatically locating a position of a first object in a physical space, comprising steps of:
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attaching a transducer to a coordinate space digitizer having a defined coordinate system in said physical space; pulsing said transducer while translating it along a surface of interest near said first object; receiving echoes from said pulsed transducer arising from a difference in an acoustic impedance of a first portion of the first object and an acoustic impedance of a material located near said first portion of the first object; and determining automatically a coordinate position in said defined coordinate system of said first object in response to said received echoes and a position and orientation of said transducer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for automatic amplitude-mode ultrasound location of an implanted fiducial marker in a physical space, comprising steps of:
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attaching an ultrasound transducer to a coordinate space digitizer having a defined coordinate system in said physical space.; pulsing said ultrasound transducer while translating it along a surface of interest near said implanted fiducial marker; receiving echoes from said pulsed ultrasound transducer arising from a difference in an acoustic impedance of a first portion of the implanted fiducial marker and an acoustic impedance of a material located near said first portion of the implanted fiducial marker; and determining automatically a coordinate position in said defined coordinate system of said implanted fiducial marker in response to said received echoes and a position and orientation of said ultrasound transducer. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. A system for locating a position of a first object in a physical space, comprising:
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a coordinate space digitizer having a defined coordinate system in said physical space; an ultrasound transducer connected with said coordinate space digitizer; a pulser pulsing said ultrasound transducer while translating it along a surface of interest located near said first object; a receiver receiving echoes from said pulsed ultrasound transducer arising from a difference in an acoustic impedance of a first portion of the first object and an acoustic impedance of a material located near said first portion of the first object; and means for automatically determining a coordinate position in said defined coordinate system of said first object in response to said received echoes and a position and orientation of said ultrasound transducer. - View Dependent Claims (45, 46, 47, 48, 49, 50)
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51. A fiducial marker assembly comprising an imaging marker assembly including a housing containing a cavity, said imaging marker assembly comprising:
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a first portion including a first material having a first acoustic impedance; and a second portion including a second material having a second acoustic impedance which is different than said first acoustic impedance. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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63. A method for automatically locating a position of a fiducial marker implanted in a bone, comprising steps of:
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attaching a transducer to a coordinate space digitizer having a defined coordinate system; pulsing said transducer while translating it along a surface of interest near said fiducial marker; receiving echoes from said pulsed transducer arising from a difference in an acoustic impedance of a portion of the fiducial marker and an acoustic impedance of a material located near said portion of the fiducial marker; and determining a position in said defined coordinate system of said fiducial marker in response to said received echoes and a position and orientation of said transducer.
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65. A method for registering a physical space with image volumes including automatically locating a position of an object, comprising steps of.
attaching a transducer to a coordinate space digitizer having a defined coordinate system; -
pulsing said transducer while translating it along a surface of interest near said object; receiving echoes from said pulsed transducer arising from a difference in an acoustic impedance of a portion of the object and an acoustic impedance of a material located near said portion of the object; and determining a position in said defined coordinate system of said object in response to said received echoes and a position and orientation of said transducer. - View Dependent Claims (64, 66)
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67. A method for automatically locating a position of an object, comprising steps of:
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attaching a transducer to a coordinate space digitizer having a defined coordinate system; pulsing said transducer while translating it along a surface of interest near said object; receiving echoes from said pulsed transducer arising from a difference in an acoustic impedance of a portion of the object and an acoustic impedance of a material located near said portion of the object; and determining a position in said defined coordinate system of said object in response to said received echoes and a position and orientation of said transducer, wherein said determining step comprises steps of; extracting a windowed surface echo signal from said received echoes; calculating a standard deviation of said extracted windowed surface echo signal; calculating a weighted centroid of positions of said transducer; locating a time delay of said windowed surface echo signal nearest the weighted centroid; calculating a depth of a center of the object in response to a depth of an interface in which said object is located and a height of said object; and calculating coordinates in said coordinate system of the center of the object in response to said calculated depth and said time delay.
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68. A method for automatically locating a position of an object, comprising steps of:
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attaching a transducer to a coordinate space digitizer having a defined coordinate system; pulsing said transducer while translating it along a surface of interest near said object; receiving echoes from said pulsed transducer arising from a difference in an acoustic impedance of a portion of the object and an acoustic impedance of a material located near said portion of the object; and determining a position in said defined coordinate system of said object in response to said received echoes and a position and orientation of said transducer; wherein said acoustic impedance of said portion of said object is lower than said acoustic impedance of said material located near said portion of said object.
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69. A method for automatic amplitude-mode ultrasound location of a fiducial marker implanted in a bone, comprising steps of:
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attaching an ultrasound transducer to a coordinate space digitizer having a defined coordinate system; pulsing said ultrasound transducer while translating it along a surface of interest near said implanted fiducial marker; receiving echoes from said pulsed ultrasound transducer arising from a difference in an acoustic impedance of a portion of the implanted fiducial marker and an acoustic impedance of a material located near said portion of the implanted fiducial marker; and determining a position in said defined coordinate system of said implanted fiducial marker in response to said received echoes and a position and orientation of said ultrasound transducer. - View Dependent Claims (70)
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71. A method for automatic amplitude-mode ultrasound location of an implanted fiducial marker including a marker body and a cap together enclosing a space, comprising steps of:
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attaching an ultrasound transducer to a coordinate space digitizer having a defined coordinate system; pulsing said ultrasound transducer while translating it along a surface of interest near said implanted fiducial marker; receiving echoes from said pulsed ultrasound transducer arising from a difference in an acoustic impedance of a portion of the implanted fiducial marker and an acoustic impedance of the cap of the implanted fiducial marker; and determining a position in said defined coordinate system of said implanted fiducial marker in response to said received echoes and a position and orientation of said ultrasound transducer. - View Dependent Claims (72)
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73. A method for registering physical space with image volumes including automatic amplitude-mode ultrasound location of an implanted fiducial marker, comprising steps of:
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attaching an ultrasound transducer to a coordinate space digitizer having a defined coordinate system; pulsing said ultrasound transducer while translating it along a surface of interest near said implanted fiducial marker; receiving echoes from said pulsed ultrasound transducer arising from a difference in an acoustic impedance of a portion of the implanted fiducial marker and an acoustic impedance of a material located near said portion of the implanted fiducial marker; and determining a position in said defined coordinate system of said implanted fiducial marker in response to said received echoes and a position and orientation of said ultrasound transducer. - View Dependent Claims (74)
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75. A method for automatic amplitude-mode ultrasound location of an implanted fiducial marker, comprising steps of:
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attaching an ultrasound transducer to a coordinate space digitizer having a defined coordinate system; pulsing said ultrasound transducer while translating it along a surface of interest near said implanted fiducial marker; receiving echoes from said pulsed ultrasound transducer arising from a difference in an acoustic impedance of a portion of the implanted fiducial marker and an acoustic impedance of a material located near said portion of the implanted fiducial marker; and determining a position in said defined coordinate system of said implanted fiducial marker in response to said received echoes and a position and orientation of said ultrasound transducer, wherein said determining step comprises steps of; extracting a windowed surface echo signal from said received echoes; calculating a standard deviation of said extracted windowed surface echo signal; calculating a weighted centroid of positions of said ultrasound transducer; locating a time delay of said windowed surface echo signal nearest the weighted centroid; calculating a depth of a center of the implanted fiducial marker in response to a depth of an interface in which said implanted fiducial marker is located and a height of said implanted fiducial marker; and calculating coordinates in said coordinate system of the center of the implanted fiducial marker in response to said calculated depth and said time delay.
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76. A method for automatic amplitude-mode ultrasound location of an implanted fiducial marker, comprising steps of:
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attaching an ultrasound transducer to a coordinate space digitizer having a defined coordinate system; pulsing said ultrasound transducer while translating it along a surface of interest near said implanted fiducial marker; receiving echoes from said pulsed ultrasound transducer arising from a difference in an acoustic impedance of a portion of the implanted fiducial marker and an acoustic impedance of a material located near said portion of the implanted fiducial marker; and determining a position in said defined coordinate system of said implanted fiducial marker in response to said received echoes and a position and orientation of said ultrasound transducer; wherein said acoustic impedance of said portion of said implanted fiducial marker is lower than said acoustic impedance of said material located near said portion of said implanted fiducial marker.
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77. A system for locating a position of an implanted fiducial marker, said implanted fiducial marker including a housing and a cap, said housing and cap together containing a cavity, said system comprising:
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a coordinate space digitizer having a defined coordinate system; an ultrasound transducer connected with said coordinate space digitizer; a pulser pulsing said ultrasound transducer while translating it along a surface of interest located near said implanted fiducial marker; a receiver receiving echoes from said pulsed ultrasound transducer arising from a difference in an acoustic impedance of a portion of the implanted fiducial marker and an acoustic impedance of the cap of the implanted fiducial marker; and means for determining a position in said defined coordinate system of said implanted fiducial marker in response to said received echoes and a position and orientation of said ultrasound transducer.
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78. A fiducial marker assembly comprising an imaging marker assembly comprising:
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a portion including a material having a first acoustic impedance; a housing; and a marker cap, said housing and said cap together containing a cavity, said cap having a second acoustic impedance which is different than said first acoustic impedance. - View Dependent Claims (79)
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80. A fiducial marker assembly comprising an imaging marker assembly having a housing, said housing containing a cavity, comprising:
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a first portion including a first material having a first acoustic impedance; and a second portion including a second material having a second acoustic impedance which is different than said first acoustic impedance, said second portion comprising a layer near an end of said fiducial marker; wherein said second acoustic impedance is higher than said first acoustic impedance.
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Specification