Magnetic Detector Probe Core Thermal Management
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Solution Overview
Problem
Existing medical devices for detecting magnetic nanoparticles in tissue localization during surgery face challenges such as thermal effects, diamagnetic interference, and eddy currents, which reduce sensitivity and accuracy, especially in smaller probe designs.
Innovation Solution
The use of a probe with a core material having high thermal diffusivity and low thermal expansion, along with a secondary magnetic drive field at a lower frequency, to minimize thermal effects and distinguish nanoparticle signals from interference, while maintaining sensitivity through optimized coil configurations and signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the probe size is reduced to improve surgical accessibility, then the probe can access tighter anatomical spaces, but thermal effects cause coils to shift and sensitivity decreases
Solution Approach 1:
The patent changes the thermal parameters of the probe core material by selecting materials with high thermal diffusivity (≥20×10−6 m2/s) and specific thermal expansion coefficients (−5/°C or −6/°C). This parameter change allows the small probe to rapidly equalize temperatures between coils, preventing thermal drift while maintaining compact size for surgical accessibility.
Solution Approach 2:
The patent employs composite material selection for the probe core, combining materials with complementary thermal properties. The core material serves dual functions: providing structural support for the coils while simultaneously acting as a thermal equalization medium. This composite approach enables the small probe to maintain coil stability despite its reduced size.
2Measurement precision
If thermal effects are reduced to improve coil stability, then detection accuracy improves, but probe design complexity increases
Solution Approach 1:
The probe core material serves itself by performing dual functions: providing mechanical support for the coils and simultaneously managing thermal equalization. The high thermal diffusivity material automatically equalizes temperatures between coils without requiring external active cooling or heating systems, thereby improving coil stability while avoiding additional system complexity.
3Measurement precision
If a secondary magnetic drive field is added to distinguish nanoparticle signals from interference, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent employs periodic magnetic drive fields at two distinct frequencies: a primary frequency to excite magnetic nanoparticles and a secondary frequency to modulate the field. This periodic action at multiple frequencies creates unique signal signatures that allow differentiation between nanoparticle signals and interference from diamagnetic materials or eddy currents, thereby improving signal discrimination.
Solution Approach 2:
The patent introduces dynamic modulation of the magnetic drive field by adding a secondary frequency component. This dynamic approach allows the system to actively distinguish signals based on their frequency response characteristics, enabling real-time differentiation between target nanoparticles and background interference without requiring complex hardware modifications.
4Measurement precision
If higher frequency drive signals are used to improve sensitivity, then detection capability improves, but eddy current interference increases
Solution Approach 1:
The patent uses feedback through frequency analysis to distinguish nanoparticle signals from eddy current interference. By detecting signals at the primary drive frequency and its harmonics while filtering out continuous interference, the system maintains high detection sensitivity even when operating at frequencies that could induce eddy currents in surrounding metallic objects.
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
This approach enhances the sensitivity and accuracy of magnetic nanoparticle detection, reducing thermal drift and interference, allowing for effective localization in smaller probes and distinguishing nanoparticles from other metallic objects.
Implementation Method 1
The probe core comprises a material with a thermal diffusivity of substantially ≧20×10−6 m2/s
Implementation Method 2
two drive coils, one each of the drive coils being located in a respective one of the regions
Implementation Method 3
two sense coils, one each of the sense coils being located in a respective one of the regions
Implementation Method 4
a source of a secondary magnetic drive field wherein the frequency of the drive signal of the secondary magnetic drive field is less than the frequency of the drive signal of the primary drive coils
Data Source
AI summary
A probe and method for detecting magnetic particles. In one embodiment, the probe includes a probe core having a first end and a second end, the probe core defining two regions for containing coils of wire, one of the regions being adjacent the first end of the cylindrical probe core; two sense coils, one each of the sense coils being located in a respective one of the regions; and two drive coils, one each of the drive coils being located in a respective one of the regions, wherein the regions are separated by a distance equal to or greater than the diameter of one of the coils and a source of a secondary magnetic drive field. In another embodiment, the frequency of the drive signal of the secondary magnetic drive field is less than the frequency of the drive signal of the primary drive coils.