Ferrofluid Sensor for Medical Tracking
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Solution Overview
Problem
Current Electromagnetic Tracking (EMT) systems face challenges in accurately tracking medical devices within the body, especially in hard-to-reach locations, due to limitations in sensor design and material compatibility, which can lead to damage to anatomy and reliance on ionizing radiation for imaging.
Innovation Solution
A sensor system utilizing a ferrofluid-filled shell with biocompatible and biodegradable materials, capable of distorting a magnetic field for precise tracking, allowing for flexible insertion and removal, and using superparamagnetic iron oxide nanoparticles to maintain magnetic properties under mechanical stress, enabling accurate 6DoF tracking without damaging the patient's anatomy and reducing radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rigid sensor is used for tracking, then tracking precision is improved, but damage to patient anatomy occurs during insertion
Solution Approach 1:
The sensor is enclosed in a flexible shell that can deform during insertion to navigate anatomical structures, then maintains rigidity when deployed for tracking. This flexible shell allows the sensor to be inserted without damaging patient anatomy while still providing accurate tracking when in position.
Solution Approach 2:
The sensor system is divided into separate components: a flexible shell for insertion and a rigid internal structure for tracking. The ferrofluid core is separated from the shell, allowing the shell to be flexible during insertion while the internal structure maintains tracking precision.
2Ease of operation
If a permanent magnet is used to remove ferrofluid, then ferrofluid removal is improved, but residual ferrofluid remains in the body
Solution Approach 1:
The system uses adjustable magnetic field parameters (strength, gradient, temporal variation) to optimize ferrofluid removal. By changing magnetic field parameters over time and space, the system can extract nearly all ferrofluid residues from the body, addressing the incomplete removal problem.
Solution Approach 2:
The system incorporates feedback mechanisms to monitor ferrofluid removal effectiveness and adjust magnetic field parameters accordingly, ensuring complete or near-complete removal of ferrofluid from the patient's body.
3Stability of the object's composition
If the shell is made rigid for structural stability, then sensor stability is improved, but the shell cannot be inserted into difficult-to-reach locations
Solution Approach 1:
The shell transitions from a flexible state during insertion to a stable deployed state for tracking. The shell can deform dynamically during insertion to reach difficult locations, then maintains stability when deployed for sensor operation.
Solution Approach 2:
The rigid tracking structure is nested within the flexible shell. During insertion, the flexible shell dominates the mechanical behavior, allowing deformation. Once deployed, the nested rigid structure provides the necessary stability for accurate tracking.
4Loss of information
If ionizing radiation is used for imaging, then anatomical visualization is improved, but patient radiation exposure increases
Solution Approach 1:
The system replaces ionizing radiation-based imaging with magnetic field-based tracking. The ferrofluid-filled sensor interacts with magnetic fields to provide anatomical visualization and tracking information without using ionizing radiation, thereby eliminating radiation exposure risks.
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
The system provides accurate and safe tracking of medical devices within the body, minimizing anatomical damage and reducing reliance on ionizing radiation, while allowing for flexible and safe insertion and removal of the sensor, enhancing the precision and safety of medical procedures.
Implementation Method 1
The sensor includes a shell that contains a ferrofluid. The ferrofluid causes distortion of the magnetic field when the ferrofluid is in proximity to the magnetic field.
Implementation Method 2
The ferrofluid includes superparamagnetic iron oxide nanoparticles (SPIONs)
Implementation Method 3
one or more field measuring coils configured to measure a characteristic of the magnetic field when the ferrofluid is in proximity to the magnetic field
Implementation Method 4
The ferrofluid may be removed by piercing the shell and magnetically pulling the ferrofluid out of the body using a permanent magnet
Data Source
AI summary
A system comprising: one or more field generating coils configured to generate a magnetic field; a sensor comprising a shell that contains a ferrofluid, the sensor configured to be introduced in proximity to the magnetic field, wherein the ferrofluid causes distortion of the magnetic field when the ferrofluid is in proximity to the magnetic field; and one or more field measuring coils configured to: measure a characteristic of the magnetic field when the ferrofluid is in proximity to the magnetic field; and provide, to a computing device, a signal representative of the measured characteristic of the magnetic field, wherein the computing device is configured to determine one or both of a position and an orientation of the sensor based on the measured characteristic of the magnetic field.