Electromagnetic Needle Position Tracking via Field Gradient Sensing
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Solution Overview
Problem
Accurately tracking the position of medical instruments within a patient's body is challenging due to the sensitivity of internal tissues, and existing methods may not provide precise enough location and orientation information for safe and effective medical procedures.
Innovation Solution
A medical instrument system incorporating an electromagnet structure with a conductive coil and ancillary circuitry to generate a magnetic field, which is sensed by a sensor device to calculate the position of the needle within the body, using a control circuit to determine the needle's position based on the sensor signals and known positional relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic detection apparatus is moved about the body to locate the greatest gradient magnitude, then the position of the medical instrument can be tracked, but the procedure becomes time-consuming and complex to operate
Solution Approach 1:
The patent replaces the mechanical approach of moving a detection apparatus throughout the body with an electromagnetic field-based system. Sensors detect magnetic field gradients generated by a magnet on the medical instrument, allowing position determination without physical movement of the detection device. This substitution of mechanical detection with electromagnetic sensing resolves the contradiction by maintaining measurement precision while dramatically improving ease of operation.
2Measurement precision
If magnetic sensors are used to detect the medical instrument's position, then location information can be obtained, but the Earth's magnetic field interferes with the accuracy of detection
Solution Approach 1:
The patent extracts or removes the Earth's magnetic field interference from the measurement by using differential detection. Sensors measure magnetic field gradients rather than absolute field strengths, and the system specifically detects variations caused by the instrument's magnet while filtering out the constant Earth's field. This extraction of the harmful interference resolves the contradiction by maintaining location detection accuracy despite the presence of Earth's magnetic field.
3Measurement precision
If the detection apparatus senses magnetic field strength at multiple distances, then the medical instrument's position can be determined, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical positioning systems with electromagnetic field sensing. Instead of requiring precise mechanical movement and positioning of multiple sensors at known distances, the system uses magnetic field gradient detection to inherently determine position. The electromagnetic field provides natural spatial encoding, replacing mechanical complexity with field-based sensing that achieves position determination accuracy without requiring complex multi-distance measurement apparatus.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise tracking of the needle's position and orientation within the body, improving the accuracy and safety of medical procedures by providing real-time positional data to medical practitioners.
Implementation Method 1
an electromagnet structure having a core and a conductive coil wound around the core; and ancillary circuitry electrically coupled to the conductive coil, the ancillary circuitry configured to controllably drive an excitation signal through the conductive coil to thereby generate a magnetic field about the electromagnet structure
Data Source
AI summary
A medical system tracks the position of a portion of a medical instrument within a body of a patient. In some embodiments, the medical instrument includes a needle, a syringe, and a needle-position-tracking element positioned between the needle and the syringe and in fluid communication with both. The needle-position-tracking element includes an electromagnet structure that includes a core, a conductive coil wrapped around the core, and ancillary circuitry configured to pass a current through the conductive coil to thereby generate a magnetic field. A sensor device senses the magnetic field and generates corresponding sensor signals. A control circuit calculates the position of a portion of the medical instrument based on the sensor signals.