Optical Fiber Temperature Sensor for Cooled RF Probe
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Solution Overview
Problem
Traditional thermocouples used in cooled radiofrequency probes are labor-intensive to manufacture and suffer from operational limitations, including heat transfer issues and inaccurate temperature measurement due to their metal composition.
Innovation Solution
A medical probe assembly featuring an electrically non-conductive optical fiber temperature sensing element with a protrusion extending from the energy delivery device, allowing for accurate temperature measurement and adjustable lesion sizes by varying the optical fiber's length, and a system for delivering radiofrequency energy with a cooling mechanism to control tissue temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional metal thermocouples are used for temperature sensing in cooled radiofrequency probes, then the temperature measurement can be obtained, but the manufacturing process becomes labor intensive and complex
Solution Approach 1:
The patent replaces the traditional metal thermocouple system with an optical fiber-based temperature sensing system. The optical fiber senses temperature through optical property changes (such as Bragg grating reflectivity or fluorescence intensity) rather than through mechanical/electrical contact, eliminating the need for complex metal welding and threading operations while providing accurate temperature measurements.
Solution Approach 2:
The optical fiber acts as an intermediary between the temperature field and the measurement system. Instead of direct metal-to-metal contact required by thermocouples, the optical fiber transmits temperature information through optical signals, simplifying the manufacturing process while maintaining measurement accuracy.
2Measurement precision
If metal thermocouples are used to measure tissue temperature, then temperature data can be obtained, but heat transfer issues and inaccurate measurement occur due to metal composition
Solution Approach 1:
The patent substitutes the metal thermocouple with an optical fiber sensing element that measures temperature through optical means rather than thermal conduction. This eliminates the heat transfer interference that occurs with metal thermocouples, as the optical fiber detects temperature through optical property changes without being thermally coupled to the tissue in the same manner.
Solution Approach 2:
The optical fiber-based sensor detects temperature changes through changes in optical parameters (such as reflectivity, fluorescence, or absorption characteristics) rather than through thermal conduction. This parameter change approach allows accurate temperature measurement without the heat transfer limitations of metal composition.
3Adaptability or versatility
If cooling mechanism is added to deliver higher voltage for larger lesions, then the lesion size increases, but temperature control precision becomes more difficult to maintain
Solution Approach 1:
The patent incorporates real-time temperature feedback from the optical fiber sensor to control the radiofrequency energy delivery and cooling mechanism. The feedback signal allows the system to adjust power levels dynamically to maintain precise temperature control even as lesion size is increased through cooling-assisted voltage application.
Solution Approach 2:
The optical fiber-based temperature sensing provides distributed, real-time temperature measurement capability that enables precise feedback control. This substitution of metal thermocouples with optical sensing allows for better temperature distribution monitoring across the treatment site, improving control precision during high-voltage RF delivery.
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 optical fiber temperature sensing system provides precise temperature feedback, enabling controlled lesion sizes and minimizing heat transfer issues, thus improving the accuracy and effectiveness of radiofrequency treatments for pain management.
Implementation Method 1
The temperature sensing element includes at least one optical fiber extending therethrough such that a distal-most end of the optical fiber(s) is exposed to define a temperature sensing face
Implementation Method 2
one or more internal lumens configured for circulating a cooling fluid to a distal end of said energy delivery device
Implementation Method 3
Tissue resistance to the current causes heating of tissue adjacent resulting in the coagulation of cells
Data Source
AI summary
A medical probe assembly for delivering energy to a patient's body includes at least one probe having an elongate member with a distal region and a proximal region. The distal region includes an electrically non-conductive outer circumferential portion. The probe assembly also includes an electrically-conductive energy delivery device extending distally from the electrically non-conductive outer circumferential portion. The energy delivery device includes a conductive outer circumferential surface and one or more internal lumens configured for circulating a cooling fluid to a distal end of the energy delivery device. The probe assembly also includes a protrusion extending from the distal end of the energy delivery device. The protrusion is electrically coupled to the energy delivery device and includes a temperature sensing element extending from a distal end of the energy delivery device. The temperature sensing element includes at least one optical fiber extending therethrough such that a distal-most end thereof is exposed to define a temperature sensing face.