Dual-mode microwave transducer for intracranial temperature monitoring
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Solution Overview
Problem
Current methods for monitoring brain temperature in neonates during hypothermic treatment are invasive, inaccurate, or costly, and fail to directly measure intracranial temperature, leading to potential over-cooling of the skin and inadequate control of brain temperature.
Innovation Solution
A non-invasive microwave radiometry system with a miniature dual-mode transducer that measures both near-surface and deep brain temperatures using dual antennas, integrated with a radiometric receiver and a disposable coupler for sterile interface, ensuring accurate and continuous monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rectal temperature measurement is used to monitor brain temperature, then the measurement can be obtained non-invasively, but the measurement is indirect and slow to indicate thermal trends in the brain
Solution Approach 1:
The patent replaces mechanical/invasive temperature sensing methods (rectal probes, axillary measurements) with microwave radiometry, an electromagnetic field-based non-invasive measurement system that directly detects brain tissue temperature through the skull, eliminating the time delay and indirectness of peripheral temperature measurements
Solution Approach 2:
The patent uses microwave radiation as an intermediary to transmit thermal information from the brain tissue through the skull and scalp to the detector, enabling direct measurement of intracranial temperature without physical contact or invasive probes
2Measurement precision
If magnetic resonance spectroscopy is used to measure deep brain temperature, then non-invasive measurement is achieved, but the cost and feasibility are problematic requiring continuous monitoring in a ferromagnetic-free environment
Solution Approach 1:
The patent replaces complex magnetic resonance spectroscopy equipment with a simpler microwave radiometry system that uses microwave antennas and receivers to measure brain temperature, eliminating the need for ferromagnetic-free environments and expensive MRI infrastructure
Solution Approach 2:
The patent employs a disposable coupler between the microwave antenna and the patient's scalp, eliminating the need for expensive, complex, and maintenance-intensive MRI equipment while providing continuous monitoring capability
3Ease of manufacture
If infrared technology devices are placed in the ear to measure temperature, then the device is relatively inexpensive, but the accuracy is insufficient due to wax and moisture absorption and measurement of wrong surfaces
Solution Approach 1:
The patent replaces infrared technology with microwave radiometry, which penetrates the skull and scalp to measure brain tissue temperature directly, avoiding the accuracy problems of IR devices that measure surface temperatures affected by ear canal contaminants and environmental factors
Solution Approach 2:
The patent uses microwave radiation as an intermediary that can penetrate biological tissues including the skull and scalp, allowing direct measurement of intracranial temperature without being affected by surface contaminants like wax and moisture that interfere with infrared measurements
4Temperature
If indirect temperature measurement methods are used, then the patient's skin can be over-cooled during hypothermic treatment, but close control of brain temperature and cooling rate cannot be maintained
Solution Approach 1:
The patent provides continuous real-time feedback of brain temperature through microwave radiometry, enabling precise control of cooling and re-warming rates by directly monitoring the target tissue temperature rather than relying on indirect peripheral measurements
Solution Approach 2:
The patent uses microwave radiation as an intermediary to directly measure brain tissue temperature, allowing independent control of brain temperature from skin temperature, thereby preventing skin over-cooling while maintaining accurate brain temperature monitoring
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 reliable and continuous long-term monitoring of intracranial temperatures, preventing skin over-cooling and enabling precise control of brain temperature, thereby reducing the risk of brain injury in neonates.
Implementation Method 1
temperature monitoring apparatus using microwave radiometry
Implementation Method 2
detecting and monitoring the temperature of target brain tissue
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
Apparatus for detecting thermal radiation emanating from two different intracranial depths in a patient includes a dual-mode transducer having a working surface for placement against a patient's cranium. The transducer includes a first antenna with an aperture adjacent the working surface that first antenna being tuned to a first frequency and producing a first output signal indicative of thermal radiation received within an antenna pattern extending a selected first distance from the working surface and a second antenna having a second aperture adjacent to the working surface within the first aperture. The second antenna is tuned to a second frequency and produces a second output signal indicative of thermal radiation received within an antenna pattern extending a selected second distance from the working surface, the second distance being shorter than the first distance. The two output signals are coupled to a receiver/control unit which thereupon monitors and displays the temperature at the two intracranial depths.