Laser Diffusion Surface Modification for MRI Implant Safety
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Solution Overview
Problem
Magnetic Resonance Imaging (MRI) induces heating in electrically conductive materials due to eddy currents, posing a risk of thermal damage to patients with metal implants, as conventional high conductivity metals do not adequately reduce MRI-induced induction heating.
Innovation Solution
A method involving laser diffusion to create a modified surface layer on substrates by depositing metal atoms onto the surface, which diffuse into the bulk material, altering the electrical conductivity and reducing MRI-induced heating. This process forms a surface layer with a thickness of at least 1 nm, either increasing or decreasing the 25°C electrical conductivity by 2.5% compared to the bulk, using a laser system and metal organic compounds to control the diffusion of metal atoms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high electrical conductivity metal materials are used, then the electrical conductivity is improved, but MRI-induced induction heating increases causing thermal damage to tissues
Solution Approach 1:
The patent applies local quality by creating a surface layer with modified electrical conductivity properties distinct from the bulk material. The surface layer (1-100 micrometers thick) has different conductivity than the interior, allowing the bulk to maintain high conductivity while the surface reduces eddy current heating during MRI scans.
Solution Approach 2:
The patent uses composite materials by combining a base metal material with a surface layer having different electrical conductivity characteristics. This composite structure integrates two materials with complementary properties: the bulk provides overall conductivity while the surface layer mitigates MRI heating effects.
2Object-affected harmful factors
If the surface layer thickness is increased to reduce MRI heating, then the harmful heating effect is reduced, but the bulk material properties are compromised
Solution Approach 1:
The surface layer thickness is precisely controlled to be between 1 micrometer and 100 micrometers, creating a localized modification that affects only the surface region where eddy currents are generated. This thin surface layer is sufficient to reduce MRI heating while the bulk material (extending beyond 100 micrometers depth) retains its original high conductivity and mechanical properties.
Solution Approach 2:
The patent applies partial action by modifying only the necessary surface portion (1-100 micrometers) rather than the entire material. This partial modification is sufficient to reduce MRI-induced heating while minimizing impact on the bulk material properties, avoiding excessive action that would compromise overall material performance.
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 modified surface layer effectively reduces MRI-induced heating by altering the electrical conductivity, minimizing thermal damage to patients with metal implants during MRI scans, while maintaining the bulk material's properties unchanged.
Implementation Method 1
The coating is laser irradiated with a laser beam, wherein atoms of metal X diffuse into the outer surface
Implementation Method 2
atoms of metal X diffuse into the outer surface to form a modified surface layer
Implementation Method 3
The modified surface layer has a 25° C. electrical conductivity that is at least 2.5% above or 2.5% below a 25° C. electrical conductivity of the bulk portion
Implementation Method 4
The eddy current can heat up the electrically conductive material by the Joule effect and this process is called induction heating
Implementation Method 5
A time-varying magnetic field creates an electric field within any electrically conductive material and the electric field, in turn, induces an electric current, referred to as the 'eddy current'
Data Source
AI summary
A system for forming surface modified substrates includes a laser system, and a laser processing chamber. A laser scanner automatically controls a position of the laser beam or an x-y translating stage upon which the laser processing chamber is mounted thereon for scanning the laser beam relative to a substrate of material (M) having a bulk portion and an outer surface integrated with the bulk portion, and a coating including metal organic molecules including at least one metal X or particles of metal X on the outer surface. At laser-heated spots atoms of X from the metal coating diffuse into the outer surface to form a modified surface layer including both M and X. The modified surface layer has a thickness of 1 nm, and a 25° C. electrical conductivity ≥2.5% above or ≤2.5% below a 25° C. electrical conductivity in the bulk portion.