Luminescent Temperature Sensor for RF Surgery Interference
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Solution Overview
Problem
Conventional temperature sensors in medical engineering systems, particularly during surgical RF devices and laser treatments, face interference from environmental factors like electric disturbances and laser energy absorption, making direct temperature measurement challenging and unreliable.
Innovation Solution
A temperature sensor utilizing a luminescent medium with a light conductor that measures fluorescence quantum yield, which is independent of environmental influences, allowing for direct temperature measurement during treatments by selecting excitation and luminescence wavelengths to avoid interference and using materials like ruby crystals or functionalized plastics for high thermal conductivity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature sensors (thermocouples or thermistors) are used during laser treatment, then temperature measurement is attempted, but the sensors absorb laser energy and cannot provide accurate measurements
Solution Approach 1:
The patent introduces an intermediary substance (fluorescent marker or luminescent material) that does not absorb laser energy directly for heating but instead converts laser excitation into measurable luminescence signals. This intermediary transfers the temperature information from the tissue to the detector without being affected by the harmful laser heating, thereby resolving the contradiction between measurement capability and laser interference
Solution Approach 2:
The patent replaces conventional contact-based temperature sensors (thermocouples, thermistors) with an optical measurement system using fluorescent markers and luminescence detection. This substitution eliminates the mechanical/physical contact that causes laser energy absorption, allowing temperature measurement to proceed without the harmful effects of direct laser-sensor interaction
2Measurement precision
If impedance measurement is used to monitor tissue temperature during RF treatment, then temperature progress can be inferred, but the measurement is indirect and only reflects significant tissue water evaporation at high temperatures
Solution Approach 1:
The patent utilizes luminescence intensity changes (optical property changes) of fluorescent markers as temperature increases. The luminescence quantum yield varies with temperature, providing a direct optical signal that correlates with tissue temperature. This allows early temperature changes to be detected through luminescence intensity variations, replacing the indirect and delayed impedance-based monitoring
3Measurement precision
If light transmission measurement is used to evaluate treated tissue state, then tissue condition can be assessed, but the measurement is prone to malfunctions from soiling and lacks sufficient meaning regarding actual tissue state
Solution Approach 1:
The patent uses fluorescent markers as intermediaries that are embedded in or applied to the tissue. These markers provide a controlled luminescence signal that is independent of tissue optical properties changes due to soiling or treatment. The luminescence intensity directly reflects temperature through quantum yield changes, providing a reliable measurement that is not affected by external optical interference or tissue optical property variations
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
Enables precise, interference-free temperature measurement during high-frequency and laser treatments, unaffected by soiling or electric disturbances, with the ability to monitor tissue changes and calculate tissue state using the Arrhenius coefficient, and can be integrated into surgical instruments as a dual-use spacer.
Implementation Method 1
the quantum yield, preferably the luminescence quantum yield, in particular also the fluorescence quantum yield, depends on temperature and hence is a measure for the temperature of a sensor element which may be excited to show luminescence
Implementation Method 2
a light conductor (14) which is optically connected to the sensor element (12), wherein the light conductor (14) delivers light having an excitation wavelength to the sensor element (12) and discharges the luminescence of the excited medium (13)
Data Source
AI summary
In order to provide a temperature sensor or a temperature measuring apparatus having a temperature sensor, which enables direct temperature measurement, in particular even during treatment, in particular even with HF surgical devices, it is proposed that the temperature sensor includes a sensor element with a medium which can be excited to luminescence, in particular fluorescence, and an optical waveguide which is optically connected to the sensor element and is intended to supply light to the medium at an excitation wavelength and/or to pick up and conduct light at a luminescence wavelength of the medium which can be excited to luminescence.