Automatic ultrasonic localization of targets implanted in a portion of the anatomy

A method for automatic amplitude-mode ultrasound location of an implanted fiducial marker in a physical space, comprising steps of:

• 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.

A system for locating a position of a first object in a physical space, comprising:

• 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.

A method for automatically locating a position of a fiducial marker implanted in a bone, 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 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.

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.

A method for 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, 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.

A method for 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;
• 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.

A method for automatic amplitude-mode ultrasound location of a fiducial marker implanted in a bone, comprising steps of:

• 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.

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:

• 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.

A method for registering physical space with image volumes including automatic amplitude-mode ultrasound location of an implanted fiducial marker, comprising steps of:

• 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.

A method for automatic amplitude-mode ultrasound location of an implanted fiducial marker, comprising steps of:

• 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.

A method for automatic amplitude-mode ultrasound location of an implanted fiducial marker, comprising steps of:

• 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.

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:

• 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.

A fiducial marker assembly comprising an imaging marker assembly comprising:

• 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.

A fiducial marker assembly comprising an imaging marker assembly having a housing, said housing containing a cavity, comprising:

• 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.