Shielded surgical navigation system that determines the position and orientation of the tracked object with real and virtual dipoles
First Claim
1. A surgical navigation system comprising:
- a transmitter assembly with at least one transmitter element capable of emitting electromagnetic energy, each said transmitter element, when emitting electromagnetic energy, being considered a real dipole;
a correction sensor assembly with at least one sensor element capable of sensing electromagnetic energy wherein, relative to said transmitter assembly, said correction sensor assembly is at a fixed position and orientation so as to form a transmitter-correction sensor assembly;
a tracker sensor assembly with at least one sensor element capable of sensing electromagnetic energy, wherein one of said transmitter-correction sensor assembly or said tracker sensor assembly is moveable relative to the other of said tracker sensor assembly or said transmitter-correction sensor assembly and one of said transmitter-correction sensor assembly or said tracker sensor assembly is part of a tracker attached to a surgical tool;
a shield formed of magnetically permeable material that is positioned so that a patient, said transmitter-correction sensor assembly and said tracker sensor assembly are located on one side of said shield and are both moveable relative to said shield; and
a processor connected to said tracker sensor assembly to receive at least one measurement of electromagnetic field strength from said tracker sensor assembly at least one sensor element and to said correction sensor assembly to receive at least one measurement of electromagnetic field strength from said correction sensor at least one sensor element and said processor being configured to;
based on the at least one measurement of electromagnetic field strength from said correction sensor assembly at least one sensor element, determine the location of at least one virtual dipole, the at least one virtual dipole being located on the side of shield opposite the side on which said transmitter-correction sensor assembly is located;
based on the location of the at least one real dipole, the location of the at least one virtual dipole and the at least one measurement of electromagnetic field strength of the at least one tracker sensor assembly at least one sensor element, determine the position and orientation of said tracker sensor assembly relative to said transmitter assembly.
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Accused Products
Abstract
A system for determining the position and orientation of a tracked object by measuring electromagnetic energy. The system includes a shield of magnetic permeable material positioned on one side of the object to be tracked. A transmitter emits the electromagnetic energy and there is a tracker sensor. One of the transmitter or tracker sensor is attached to the object to be tracked. A correction sensor is at fixed location relative to the transmitter assembly. Both sensors assemblies measure the electromagnetic energy emitted by the transmitter. Based on the energy measured by the correction sensor, the location of a virtual dipole that mirrors the transmitter, the real dipole, on the opposite side of the shield is determined. Based on the positions of the real and virtual dipoles and the energy measured by the tracker sensor, the position and orientation of the tracker sensor relative to the transmitter is determined.
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Citations
18 Claims
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1. A surgical navigation system comprising:
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a transmitter assembly with at least one transmitter element capable of emitting electromagnetic energy, each said transmitter element, when emitting electromagnetic energy, being considered a real dipole; a correction sensor assembly with at least one sensor element capable of sensing electromagnetic energy wherein, relative to said transmitter assembly, said correction sensor assembly is at a fixed position and orientation so as to form a transmitter-correction sensor assembly; a tracker sensor assembly with at least one sensor element capable of sensing electromagnetic energy, wherein one of said transmitter-correction sensor assembly or said tracker sensor assembly is moveable relative to the other of said tracker sensor assembly or said transmitter-correction sensor assembly and one of said transmitter-correction sensor assembly or said tracker sensor assembly is part of a tracker attached to a surgical tool; a shield formed of magnetically permeable material that is positioned so that a patient, said transmitter-correction sensor assembly and said tracker sensor assembly are located on one side of said shield and are both moveable relative to said shield; and a processor connected to said tracker sensor assembly to receive at least one measurement of electromagnetic field strength from said tracker sensor assembly at least one sensor element and to said correction sensor assembly to receive at least one measurement of electromagnetic field strength from said correction sensor at least one sensor element and said processor being configured to; based on the at least one measurement of electromagnetic field strength from said correction sensor assembly at least one sensor element, determine the location of at least one virtual dipole, the at least one virtual dipole being located on the side of shield opposite the side on which said transmitter-correction sensor assembly is located; based on the location of the at least one real dipole, the location of the at least one virtual dipole and the at least one measurement of electromagnetic field strength of the at least one tracker sensor assembly at least one sensor element, determine the position and orientation of said tracker sensor assembly relative to said transmitter assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 18)
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12. A surgical navigation system comprising:
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a transmitter assembly with at least one transmitter element capable of emitting electromagnetic energy, each said transmitter element, when emitting electromagnetic energy, being considered a real dipole; a correction sensor assembly with at least one sensor element capable of sensing electromagnetic energy is provided, wherein, relative to said transmitter assembly, said correction sensor assembly is at a fixed position and orientation so as to form a transmitter-correction sensor assembly; a tracker sensor assembly with at least one sensor element capable of sensing electromagnetic energy, wherein one of said transmitter-correction sensor assembly or said tracker sensor assembly is moveable relative to the other of said tracker sensor assembly or said transmitter-correction sensor assembly and one of said transmitter-correction sensor assembly or said tracker sensor assembly is part of a tracker attached to a surgical tool or to a marker attached to a patient; a shield formed of magnetically permeable material that is positioned so that the patient, said transmitter-correction sensor assembly and said tracker sensor assembly are located on one side of said shield, the patient is located close to said shield, said tracker sensor assembly is located further from said shield than the distance the patient is located from said shield and said transmitter-correction sensor assembly is located further from said shield than the distance said tracker sensor assembly is located from said shield and both said transmitter-correction sensor assembly and said tracker sensor assembly are moveable relative to said shield said; and a processor connected to said tracker sensor assembly to receive at least one measurement of electromagnetic field strength from said at least one tracker sensor assembly sensor element and to said correction sensor assembly to receive at least one measurement of electromagnetic field strength from said at least one correction sensor assembly sensor element and said processor being configured to; based on the at least one measurement of electromagnetic field strength from said at least one correction sensor assembly sensor element, determine the location of at least one virtual dipole, the at least one virtual dipole being located on the side of shield opposite the side on which said transmitter-correction sensor assembly is located; based on the location of the at least one real dipole, the location of the at least one virtual dipole and the at least one measurement of electromagnetic field strength of the at least one tracker sensor assembly sensor element, determine the position and orientation of said tracker sensor assembly relative to said transmitter assembly. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification