Thermoacoustic Probe Matching Layers for Energy Transfer
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Solution Overview
Problem
In thermoacoustic imaging, sub-optimal coupling of RF applicators to tissue leads to inefficient energy transfer, reduced heating rates, non-uniform energy deposition, tissue hotspots, overheating, and poor image quality due to interference from spurious acoustic waves, making it challenging to perform effectively in clinical settings, especially with handheld devices.
Innovation Solution
A thermoacoustic probe is designed with a radio-frequency (RF) applicator, an electromagnetic matching layer, an optical transducer, and an acoustic matching layer, where the acoustic matching layer is configured to minimize acoustic attenuation and has specific permittivity and impedance properties, and is formed from materials like open-cell foam or rubber-based vibration isolation materials, to enhance energy transfer and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If RF applicator is directly coupled to tissue, then energy transfer efficiency improves, but tissue overheating and non-uniform energy deposition occur
Solution Approach 1:
An electromagnetic matching layer is introduced as an intermediary component between the RF applicator and the tissue. This matching layer has specific electromagnetic properties (permittivity and conductivity) that are intermediate between the applicator and tissue, enabling smoother energy transfer and reducing localized overheating while maintaining overall energy transfer efficiency.
Solution Approach 2:
The electromagnetic properties of the matching layer are specifically engineered with controlled permittivity and conductivity parameters. By adjusting these parameters, the system achieves optimal energy distribution into the tissue, preventing both reflection losses and excessive localized heating.
2Speed
If RF applicator is directly coupled to tissue, then heating rate improves, but energy deposition uniformity worsens
Solution Approach 1:
The electromagnetic matching layer serves as a mediator that distributes electromagnetic energy more uniformly across the tissue interface. It prevents energy concentration at specific points while maintaining the overall heating rate through its optimized electromagnetic properties.
Solution Approach 2:
The matching layer has spatially varying electromagnetic properties that are optimized for different regions. This local optimization ensures uniform energy distribution across the entire tissue surface while maintaining efficient overall energy transfer and heating rate.
3Measurement precision
If RF applicator is directly coupled to tissue, then signal intensity improves, but spurious acoustic wave interference increases
Solution Approach 1:
The electromagnetic matching layer acts as a buffer that reduces the direct interaction between the strong RF field and the conductive skin layer. This intermediary layer attenuates the generation of spurious acoustic waves while preserving the detection of legitimate thermoacoustic signals from deeper tissue constituents.
Solution Approach 2:
The matching layer pre-reduces the electromagnetic field strength at the tissue interface before the field can generate harmful spurious acoustic waves. This preliminary attenuation prevents the formation of strong interfering signals while allowing legitimate signals to pass through.
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 proposed solution improves energy deposition uniformity, reduces tissue overheating, and enhances image quality by minimizing acoustic attenuation and interference, making the thermoacoustic imaging system more effective and suitable for clinical use.
Implementation Method 1
Thermoacoustic imaging uses short pulses of electromagnetic energy, such as RF pulses, directed into a subject to heat absorbing features within the subject rapidly
Implementation Method 2
heat absorbing features within the subject rapidly, which in turn induces acoustic pressure waves
Implementation Method 3
an acoustic matching layer that is coupled to the optical transducer... configured to limit acoustic attenuation
Implementation Method 4
an electromagnetic matching layer coupled to the insert of the RF applicator
Data Source
AI summary
A thermoacoustic probe for a thermoacoustic imaging system, the probe including: a radio-frequency (RF) applicator having an insert, wherein the applicator is configured to transmit at least one radio frequency source; an electromagnetic matching layer coupled to the insert of the RF applicator; an optical transducer that is coupled to the electromagnetic matching layer; and an acoustic matching layer that is coupled to the optical transducer.