Chirped Fiber Optic Sensor for Distributed Temperature Sensing
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Solution Overview
Problem
Current methods for measuring temperature during thermal tumor ablation, such as infrared cameras, thermocouples, and fiber optic sensors with uniform Bragg gratings, face limitations including invasive measurement impossibility, thermal and electromagnetic interference, low resolution, and inability for distributed temperature sensing, which affect the accuracy of thermal ablation.
Innovation Solution
A fiber optic temperature sensor with a linearly chirped Bragg grating and backscatter light spectrum decoding software is used, allowing for direct placement on the tumor and providing high-resolution, distributed temperature sensing with improved accuracy through a computer-connected system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a series of fiber optic temperature sensors with uniform Bragg grating is used, then temperature sensing is possible, but the resolution is low which negatively affects the accuracy of thermal ablation
Solution Approach 1:
The patent transforms the uniform Bragg grating structure into a linearly chirped Bragg grating structure where the grating period varies linearly along the fiber length. This parameter change in the grating periodicity enables distributed temperature sensing with high spatial resolution (50-100 μm) by creating a unique spectral signature for each position along the fiber, thereby resolving the contradiction between achieving temperature sensing and maintaining high spatial resolution.
2Ease of operation
If infrared camera is used for temperature measurement, then non-contact measurement is possible, but invasive measurement remains impossible and tissues must be absent between camera and tumor
Solution Approach 1:
The patent introduces a fiber optic sensor with linearly chirped Bragg grating as an intermediary element that can be directly inserted into the tumor tissue. This intermediary enables temperature measurement at the tumor site itself, overcoming the limitation of infrared cameras that require line-of-sight and cannot penetrate tissues. The fiber optic sensor acts as a mediator between the external measurement system and the internal tumor environment.
3Measurement precision
If thermocouples and thermistors are used, then temperature measurement is possible, but distributed temperature sensing is impossible and they are subject to thermal and electromagnetic effects
Solution Approach 1:
The patent replaces traditional electrical temperature sensors (thermocouples and thermistors) with an optical-based fiber optic sensor system. This substitution eliminates the susceptibility to electromagnetic interference that plagues electrical sensors. The fiber optic sensor uses optical wavelength shifts to indicate temperature changes, making it immune to electromagnetic fields while enabling distributed temperature sensing along the entire fiber length.
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 method enhances the accuracy and quality of thermal tumor ablation by enabling precise temperature profiling and heat distribution prediction, reducing the risk of damaging healthy tissues and improving treatment outcomes.
Implementation Method 1
a periodic variation of the refractive index with a constant period... through the fiber optic sensor... is passed a light spectrum, which undergoes backscatter due to the Bragg grating
Implementation Method 2
a linearly chirped (the variation of the refractive index has a period growing in an algebraic progression) Bragg grating
Implementation Method 3
a light spectrum, which undergoes backscatter due to the Bragg grating, dependent on the temperature acting on the sensor
Data Source
AI summary
An effective and highly accurate method for measuring temperature during thermal tumor ablation to increase ablation accuracy includes installing a fiber optic temperature sensor with a linearly chirped (the variation of the refractive index has a period growing in an algebraic progression) Bragg grating with a length of 1.4-6 cm and a diameter of 80-300 μm using a catheter directly on the tumor. Through the fiber optic sensor with a length of 1.4-6 cm and a diameter of 80-300 μm is passed a light spectrum, which undergoes backscatter due to the Bragg grating, dependent on the temperature acting on the sensor. Subsequently, using the backscatter light spectrum decoding software, developed according to the fiber optic cable parameters, the temperature profile is displayed on the computer. The method has applications in medicine, in particular oncology.