Coaxial Probe Microwave Transmission for In Situ Tissue Assessment

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Solution Overview

Problem

Existing methods for assessing physiological properties of biological tissue, such as reflection-based microwave coaxial probes and dual-energy x-ray absorptiometry, suffer from errors due to poor tissue contact, shallow penetration depth, and artefacts from surrounding tissues, making them unreliable for in situ measurements.

Innovation Solution

A transmission-based method using coaxial probes to transmit and receive microwave signals across biological tissue, allowing for improved assessment of dielectric properties like dielectric constant and conductivity, which are correlated with physiological properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If reflection-based microwave coaxial probes are used for tissue measurement, then the measurement can be performed with simple equipment, but the penetration depth is limited to approximately 0.25 mm and measurements are sensitive to poor tissue contact

Engineering Contradiction:

Improvemeasurement equipment simplicityVSAvoidmeasurement reliability

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent inverts the conventional reflection-based measurement approach by using transmission-based measurement. Instead of measuring the reflection of microwaves from the tissue surface, the system transmits microwaves through the tissue and measures the transmitted signal, thereby achieving deeper penetration and reduced sensitivity to surface contact quality.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a transmission medium (tissue itself) as an intermediary between the transmitting and receiving probes. The microwaves pass through this intermediary to carry information about the tissue's dielectric properties, enabling measurement of bulk tissue characteristics rather than just surface properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If dual-energy x-ray absorptiometry (DXA) is used to assess bone density, then a broad area can be scanned, but artefacts from overlying tissues and density variations between vertebrae reduce measurement accuracy

Engineering Contradiction:

Improvescan coverage areaVSAvoidbone density measurement accuracy

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies local quality by enabling measurement of specific localized regions of interest within the tissue. The transmission-based approach allows targeting of particular vertebrae or tissue regions, providing locally-specific dielectric property measurements rather than averaged values over large areas, thereby eliminating artefacts from surrounding tissues.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If invasive tissue removal is performed for measurement, then direct laboratory analysis can be conducted, but the procedure introduces patient risk and requires sterile equipment and laboratory access

Engineering Contradiction:

Improvetissue property measurement accuracyVSAvoidpatient risk and procedural complexity

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical/invasive tissue removal with a non-invasive electromagnetic field-based measurement system. Microwave transmission measurements are performed in situ through intact tissue, substituting physical tissue extraction and laboratory analysis with electromagnetic probing, thereby eliminating patient risk and the need for sterile procedures or laboratory equipment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provides more reliable and flexible measurements with increased penetration depth, reducing sensitivity to tissue contact and artefacts, enabling accurate assessment of tissue properties in situ.

Implementation Method 1

transmitting a microwave signal from a first coaxial probe; receiving a microwave signal at a second coaxial probe

Methodology Applied

Scientific EffectMicrowave transmission: Microwave Radiation

Implementation Method 2

assessing the at least one physiological property of the biological tissue based on measures of the microwave signal transmitted and received across the biological tissue between the coaxial probes

Methodology Applied

Scientific EffectDielectric properties: Dielectric Permittivity

Data Source

PatentUS12357187B2Systems and methods for assessing a physiological property of a biological tissue based on its microwave transmission properties

Publication Date: 2025.07.15 PROBINGON AB

AI summary

According to one aspect of the invention, a method for assessing physiological properties of a biological tissue is provided. The method comprising the steps of transmitting from a first coaxial probe, receiving at a second coaxial probe and assessing physiological properties. The transmission from the first probe is a microwave signal. The second coaxial probe receives a microwave signal. The first coaxial probe and the second coaxial probe are arranged in connection with the biological tissue. The physiological properties of the biological tissue between the coaxial probes are assessed based on the microwave signal transmitted and received across the biological tissue. The invention further relates to a system and a coaxial probe useful in performing such a method.