Magnetic Seed Localization Using Anisotropic Field Detection

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Solution Overview

Problem

Current methods for guiding breast conserving surgery, such as wire localization breast biopsy (WLBB) and radioactive seed localization (RSL), are invasive, costly, and inefficient, with wire dislodgment and radiation exposure issues, respectively, necessitating a less invasive and non-radioactive localization method.

Innovation Solution

A magnetic detector system using non-radioactive magnetic seeds implanted to mark tumors, combined with a detector probe and processor to accurately locate the seeds using anisotropic magnetic field geometry, providing precise surgical guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wire localized breast biopsy (WLBB) is used to guide accurate excision of non-palpable lesions, then localization precision is improved, but patient comfort deteriorates due to wire implantation pain and risk of dislodgment

Engineering Contradiction:

Improvelocalization precisionVSAvoidpatient discomfort

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical wire localization system with a magnetic field-based detection system. Instead of using a physical wire that causes patient discomfort and dislodgment risks, the invention uses magnetic seeds that generate magnetic fields detectable by sensors, eliminating mechanical intrusion while maintaining localization precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and detection parameters from mechanical (wire position) to magnetic (field strength and direction). By detecting magnetic field parameters rather than physical wire position, the system achieves accurate localization without the harmful mechanical effects of wire implantation.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If radioactive seed localization (RSL) is used to mark tumor center and borders, then patient flow and comfort are improved, but radiation exposure and regulatory complexity increase

Engineering Contradiction:

Improvepatient flow and comfortVSAvoidradiation exposure

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes the radioactive seed system with a non-radioactive magnetic seed system. The magnetic seeds provide the same localization function without emitting radiation, eliminating radiation exposure risks while maintaining ease of operation and patient comfort benefits.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent converts the potentially harmful radioactive properties into harmless magnetic properties. By using magnetic fields instead of radiation, the system retains the benefits of seed localization (contained within breast, preventing movement) while eliminating the harmful radiation exposure to patients and staff.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If wire is implanted under mammographic compression to mark lesion location, then localization accuracy is improved, but surgical incision placement deteriorates resulting in suboptimal cosmesis

Engineering Contradiction:

Improvelocalization accuracyVSAvoidcosmetic outcome

Core Design Contradiction:

Measurement precisionVSShape

Solution Approach 1:

The patent introduces dynamic adaptability to the localization system. Magnetic seeds can be implanted in various orientations and positions, and the detection system can locate them from different angles, allowing surgical incisions to be planned for optimal cosmetic outcomes while maintaining localization accuracy, unlike fixed wire trajectories.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes from fixed mechanical wire trajectories to flexible magnetic field detection. This allows the surgical team to choose incision locations that optimize cosmesis while the magnetic detection system provides accurate localization data from any approach angle.

Inventive Principle:

Principle #35Parameter changes

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 accurate and efficient localization of tumors with reduced patient discomfort and operational costs, ensuring optimal cosmetic and oncologic outcomes by allowing precise surgical planning and execution.

Implementation Method 1

The first magnetic sensor and the second magnetic sensor detect a magnetic field generated by a magnetic seed and in response thereto generate signal data representative of the magnetic field

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

Processing the signal data includes accounting for an anisotropic geometry of the magnetic field generated by the magnetic seed

Methodology Applied

Scientific EffectAnisotropic magnetic field geometry: Anisotropy

Data Source

PatentUS12419534B2System and method for magnetic occult lesion localization and imaging

Publication Date: 2025.09.23 STRYKER CORP

AI summary

Systems and methods for marking the location and extent of an anatomical region-of-interest, such as a tumor, using magnetic seeds whose position and orientation are measured or otherwise detected using a detection device that includes two or more magnetic sensors are described. One or more magnetic seeds are implanted to mark and define the center and extent of an anatomical region-of-interest and a magnetic sensor-based detector system is used to accurately identify the location of the magnetic seeds.