Optical Fiber Attenuation Estimation for Blood-Affected Tissue Dosimetry
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Solution Overview
Problem
Existing light-based therapies using optical fibers for medical treatments, such as photodynamic therapy and laser hyperthermia, face challenges due to blood accumulation at the distal ends of optical fibers, leading to reduced light dose delivery and inaccurate optical measurements, particularly in treating deeper tumors.
Innovation Solution
A system and method for determining light attenuation caused by blood aggregation using a model-based algorithm, involving optical measurements and a two-step process to estimate attenuation values, utilizing a plurality of optical members and solving inverse problems to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If optical fibers are inserted into tissue for light-based therapy, then light delivery to deep tumors is enabled, but blood accumulation at the distal ends of optical fibers attenuates the light and reduces treatment efficacy
Solution Approach 1:
The system performs preliminary optical measurements to detect blood accumulation and calculate attenuation coefficients before initiating treatment. By measuring light transmission through the optical fiber and comparing it against reference values, the system pre-characterizes the tissue-optical fiber interface conditions, allowing for accurate light dose calculations during therapy delivery.
Solution Approach 2:
The system continuously monitors light transmission through the optical fiber during treatment and uses this feedback to calculate real-time attenuation coefficients. By comparing actual light transmission measurements with expected values and adjusting the attenuation compensation factors accordingly, the system maintains accurate light dose delivery despite dynamic changes in blood accumulation.
2Adaptability or versatility
If multiple optical fibers are used to treat all tumour cells, then treatment coverage is improved, but the complexity of measuring and calculating light flux through multiple fibers increases
Solution Approach 1:
The system uses a universal measurement approach where the same optical fiber serves both as the light delivery medium and as the sensing element for attenuation measurement. By measuring light transmission through each fiber individually and using standardized reference values, the system eliminates the need for separate measurement apparatus for each fiber, thereby reducing overall system complexity while maintaining comprehensive treatment coverage.
Solution Approach 2:
The optical fibers themselves perform the measurement function by transmitting light that can be detected at the proximal end. The fibers self-characterize their attenuation properties through the light transmission measurements, eliminating the need for external measurement devices or complex multi-fiber measurement systems. Each fiber measures its own transmission characteristics using the therapy light itself.
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
Enhances the accuracy of light dose delivery and optical measurements by accurately estimating effective attenuation coefficients, thereby improving treatment efficacy and dosimetry in light-based therapies.
Implementation Method 1
the attenuation may reduce the intended effect of the treatment since the light dose further away from the fibres is reduced
Implementation Method 2
a system for determining light attenuation at optical members inserted in tissue
Data Source
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AI summary
A system and method for determining or estimating the presence and effect of light-attenuating inhomogeneities in tissue when performing medical treatment or diagnostics using optical members in tissue. The system and method comprising inserting a plurality of optical members into the tissue, and then measuring by emitting light through a sub-set of optical members at a time, while measuring the light collected by another sub-set of optical members. Combining said measurement data with a model for light propagation in tissue, and setting up a system of equations. Solving the unknown attenuation values from said system of equations.