Abstract: A method and system for locating a source of a signal. The source may be a wireless marker that is implanted in an object, such as a human body. The signal generated by the marker is a magnetic field. The location system uses an array of sensors to measure the magnetic field of the marker at various sensor locations. The location system compares the set of actual measurements to sets of reference measurements for various known locations within a bounding volume. Based on the comparisons, the location system identifies the set of reference measurements that most closely matches the set of actual measurements. The location system then uses sets of reference measurements for known locations near the closest known location to more accurately determine the marker location when it is not actually at one of the known locations.

Abstract: One embodiment of such a system comprises a sensor assembly mounted in a fixed location relative to a machine isocenter. According to another embodiment, the sensor assembly includes a fixed mounting bracket and an articulating arm allowing movement of the sensor assembly while allowing translation of the sensor assembly location with reference to the machine isocenter According to still another embodiment, the sensor assembly is positioned in a fixed relationship relative to the patient support assembly, mounted below the patient support assembly, as an overlay on the patient support assembly or integral to and forming a portion of the patient support assembly. The sensor assembly location is referenced to the machine isocenter through the relation of the table to the machine isocenter or through an independent locating system for the sensor assembly. According to yet another embodiment, the sensor assembly is located relative to machine isocenter by conventional imaging techniques.

Abstract: A method and system for locating a source of a signal. The source may be a wireless marker that is implanted in an object, such as a human body. The signal generated by the marker is a magnetic field. The location system uses an array of sensors to measure the magnetic field of the marker at various sensor locations. The location system compares the set of actual measurements to sets of reference measurements for various known locations within a bounding volume. Based on the comparisons, the location system identifies the set of reference measurements that most closely matches the set of actual measurements. The location system then uses sets of reference measurements for known locations near the closest known location to more accurately determine the marker location when it is not actually at one of the known locations.

Abstract: A system for generating a magnetic field for excitation of a leadless marker assembly. The system of at least one embodiment includes a source generator that generates a plurality of alternating electrical signals each having an independently adjustable phase. A plurality of excitation coils are configured to simultaneously receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field. The phase of the alternating electrical signal for each excitation coil is independently adjustable relative to the phase of the alternating electrical signal for the other excitation coils so as to adjust the magnetic field from the respective coil. The magnetic fields from the excitation coils combine to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

Abstract: A receiver for determining the location of a marker that is excited with an exciting waveform. A sensing array having coils is used to sense magnetic flux from the resonating marker. The coils provide inputs to the receiver. The receiver includes a correlation processor for analyzing the inputs in a coherent manner. Further, the receiver is synchronized to act on inputs that are gathered when a treatment radiation source is inactive.

Abstract: Instruments and method of using instruments for implanting electrodes into a patient. The instrument can include a body configured to be implanted into a patient, an electrode contact carried by the body, and a marker carried by the body. The electrode contact has an electrically conductive surface exposed at a location along the body to sense electrical activity and/or deliver electrical stimulation to the target neural structure. The marker can include a transponder configured to be energized by a wirelessly transmitted excitation energy and to wirelessly transmit a location signal in response to the excitation energy. The instrument is tracked as it is implanted into the patient by time multiplexing the wirelessly transmitted excitation energy and the location signal such that the absolute location of the marker can be determined in real time.

Abstract: Instruments and methods for tracking such instruments in a human patient. One embodiment of an instrument in accordance with the invention comprises an elongated body, such as an elongated flexible member, which has a distal section configured to be passed through a vessel or other passageway in a human. The instrument can further include a lumen through the distal section and a magnetic marker having a transponder at the distal section. The transponder includes a circuit configured to be energized by a wirelessly transmitted magnetic excitation energy and to wirelessly transmit a magnetic location signal in response to the excitation energy. The magnetic marker, for example, can be attached to or otherwise integral with the instrument.

Abstract: Electromagnetic transponders as markers are used to localize and guide orthopedic procedures including: knee replacement, hip replacement, shoulder replacement, damaged bone reconstruction, and spine surgery, and more particularly, to guide orthopedic surgical navigation and alignment techniques and instruments. For example, the marker could further be used in any number of guides or templates that attach to the bony anatomy, such as a surgical guide, cutting guide, cutting jig, resection block and/or resurfacing guide. Further, the marker could be incorporated into an existing intramedullary guide rod for a femur and an extramedullary guide rod for a tibia in a knee replacement surgery; or into an external surgical guide system, or the marker could eliminate the need for an external template altogether. According to yet another anticipated use of the tracking system, the marker could be used in conjunction with or replace an optical alignment system.

Abstract: Systems and methods for locating and tracking a target, i.e., measuring the position and/or rotation of a target during setup and treatment of a patient in guided radiation therapy applications for the head and neck. One embodiment is directed toward a device having a body and markers, such as excitable transponders and/or radiographic fiducials, fixable in or on the body for localizing the body. For example, the body can be a mouthpiece body having a channel configured to receive a patient's teeth such that the mouthpiece is repeatedly and consistently placed in the same relative position in the patient when the patient bites down on the mouthpiece. The transponders can be alternating magnetic transponders and the fiducials can be gold seeds. Other embodiments include a device having a two-piece body, a first piece of the body having excitable transponders and a second piece of the body having radiographic fiducials.

Abstract: A system for generating a magnetic field for excitation of a leadless marker assembly. The system of at least one embodiment includes a source generator that generates a plurality of alternating electrical signals each having an independently adjustable phase. A plurality of excitation coils are configured to simultaneously receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field. The phase of the alternating electrical signal for each excitation coil is independently adjustable relative to the phase of the alternating electrical signal for the other excitation coils so as to adjust the magnetic field from the respective coil. The magnetic fields from the excitation coils combine to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

Abstract: A receiver for determining the location of a marker that is excited with an exciting waveform. A sensing array having coils is used to sense magnetic flux from the resonating marker. The coils provide inputs to the receiver. The receiver includes a correlation processor for analyzing the inputs in a coherent manner. Further, the exciting waveform is repeated with random dithering in order to eliminate system noise.

Abstract: A receiver for determining the location of a marker that is excited with an exciting waveform. A sensing array having coils is used to sense magnetic flux from the resonating marker. The coils provide inputs to the receiver. The receiver includes a correlation processor for analyzing the inputs in a coherent manner. The receiver determines the phase component of each of the inputs and compensates for differences.

Abstract: A system for generating a magnetic field for excitation of a leadless marker assembly. The system of at least one embodiment includes a source generator that generates a plurality of alternating electrical signals each having an independently adjustable phase. A plurality of excitation coils are configured to simultaneously receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field. The phase of the alternating electrical signal for each excitation coil is independently adjustable relative to the phase of the alternating electrical signal for the other excitation coils so as to adjust the magnetic field from the respective coil. The magnetic fields from the excitation coils combine to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

Abstract: A method and system for locating a source of a signal. The source may be a wireless marker that is implanted in an object, such as a human body. The signal generated by the marker is a magnetic field. The location system uses an array of sensors to measure the magnetic field of the marker at various sensor locations. The location system compares the set of actual measurements to sets of reference measurements for various known locations within a bounding volume. Based on the comparisons, the location system identifies the set of reference measurements that most closely matches the set of actual measurements. The location system then uses sets of reference measurements for known locations near the closest known location to more accurately determine the marker location when it is not actually at one of the known locations.

Abstract: Embodiments of the invention are directed to an apparatus for use in a system that senses an excitable wireless target capable of being implanted in a body or tissue. The apparatus includes multiple electromagnetic field sensors arranged approximately in a common plane, and multiple sense signal output paths coupled to the sensors. Each one of the sensors and corresponding output paths is configured to provide an output signal representing at least a portion of an electromagnetic field provided by the marker, where the output signal is proportional to a component of the field at the sensor, where that component is substantially perpendicular to the plane. Various other configurations regarding this apparatus, as well as the overall system and methods of exciting and receiving signals from wireless markers, are also disclosed.

Abstract: A system for generating a magnetic field for excitation of a leadless marker assembly. The system of at least one embodiment includes a source generator that generates a plurality of alternating electrical signals each having an independently adjustable phase. A plurality of excitation coils are configured to simultaneously receive a respective one of the alternating electrical signals at a selected phase to generate a magnetic field. The phase of the alternating electrical signal for each excitation coil is independently adjustable relative to the phase of the alternating electrical signal for the other excitation coils so as to adjust the magnetic field from the respective coil. The magnetic fields from the excitation coils combine to form a spatially adjustable excitation field for excitation of the remote leadless marker assembly.

Abstract: An ultrasonic imaging system and method form first and second transmit beams characterized by a complex phase separation angle (e.g. 90°) that differs from an integer multiple of 180° along the same steering angle. First and second backscattered signals are received in response to these transmit beams, and the first and second backscattered signals are combined in a weighted sum. By properly selecting the weighting factors and the separation angle, the resulting combined signal can be provided with various advantageous features, such as a selective reduction in negative frequency components, a selective enhancement of fundamental frequency components, or a selective enhancement of harmonic frequency components.

Abstract: An ultrasonic imaging system and method form first and second transmit beams characterized by a complex phase separation angle (e.g. 90°) that differs from an integer multiple of 180° along the same steering angle. First and second backscattered signals are received in response to these transmit beams, and the first and second backscattered signals are combined in a weighted sum. By properly selecting the weighting factors and the separation angle, the resulting combined signal can be provided with various advantageous features, such as a selective reduction in negative frequency components, a selective enhancement of fundamental frequency components, or a selective enhancement of harmonic frequency components.

Abstract: The present invention includes a fully programmable plurality of multi-channel receivers, each receiver having a digital multi-channel receive processor and a local processor control. Each receive processor includes a first decimator, time delay memory, second decimator, and complex multiplier. The receive beamformer is a computationally efficient system which is programmable to allow processing mode trade-offs among receive frequency, receive spatial range resolution, and number of simultaneous beams received. Each local control receives focusing data from a central control computer and provides final calculation of per-channel dynamic focus delay, phase, apodization, and calibration values for each receiver signal sample. Further, this invention includes a baseband multi-beam processor which has a phase aligner and a baseband filter for making post-beamformation coherent phase adjustments and signal shaping, respectively.

Abstract: The present invention includes a fully programmable plurality of multi-channel receivers, each receiver having a digital multi-channel receive processor and a local processor control. Each receive processor includes a first decimator, time delay memory, second decimator, and complex multiplier. The receive beamformer is a computationally efficient system which is programmable to allow processing mode trade-offs among receive frequency, receive spatial range resolution, and number of simultaneous beams received. Each local control receives focusing data from a central control computer and provides final calculation of per-channel dynamic focus delay, phase, apodization, and calibration values for each receiver signal sample. Further, this invention includes a baseband multi-beam processor which has a phase aligner and a baseband filter for making post-beamformation coherent phase adjustments and signal shaping, respectively.