Photodynamic Therapy Parameter Modeling With PpIX Regression
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Solution Overview
Problem
Existing photodynamic therapy (PDT) methods lack a clear understanding of the relationship between intracellular protoporphyrin IX accumulation and light irradiation energy density, leading to excessive normal cell death or insufficient target cell killing, with no standardized method to determine optimal therapy parameters.
Innovation Solution
A method and apparatus that utilize a regression analysis to establish a correlation between intracellular protoporphyrin IX accumulation, light irradiation energy density, and cell viability, allowing for the determination of optimal therapy parameters through a four-parameter logistic model, enabling precise control of light irradiation energy and photosensitizer dose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light irradiation energy density is increased to kill target cells, then target cell killing effect is improved, but normal cell death increases
Solution Approach 1:
The patent applies parameter changes by establishing a quantitative relationship between light irradiation energy density and intracellular PpIX accumulation. By measuring PpIX levels and using regression analysis to determine optimal light energy parameters, the treatment achieves sufficient target cell killing while avoiding excessive normal cell damage. This data-driven parameter optimization resolves the contradiction between effective treatment and side effect minimization.
2Object-affected harmful factors
If light irradiation energy density is decreased to reduce side effects, then normal cell death is reduced, but target cell killing effect becomes insufficient
Solution Approach 1:
The patent implements feedback control by measuring intracellular PpIX accumulation levels and using this information to determine the appropriate light irradiation energy density. The regression analysis model provides a feedback mechanism that adjusts treatment parameters based on actual photosensitizer accumulation, ensuring sufficient target cell killing while minimizing normal cell damage. This resolves the contradiction by making treatment efficacy dependent on measured biological response rather than fixed parameters.
3Reliability
If photosensitizer dose is increased to improve target cell killing, then target cell killing effect is improved, but side effects on normal cells increase
Solution Approach 1:
The patent applies parameter changes by establishing a quantitative relationship between photosensitizer dose and intracellular PpIX accumulation. By measuring actual PpIX levels and using regression analysis to determine optimal treatment parameters, the system achieves effective target cell killing with minimal photosensitizer dose, thereby reducing side effects on normal cells. This data-driven approach optimizes the dose parameter to resolve the contradiction.
4Object-affected harmful factors
If photosensitizer dose is decreased to reduce side effects, then side effects on normal cells are reduced, but target cell killing effect becomes insufficient
Solution Approach 1:
The patent implements feedback control by measuring intracellular PpIX accumulation and using this information to determine the appropriate photosensitizer dose and light irradiation parameters. The regression analysis model provides a feedback mechanism that ensures sufficient target cell killing even with reduced photosensitizer doses by optimizing the combination of dose and light energy parameters. This resolves the contradiction between reduced side effects and maintained efficacy.
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 approach allows for the precise determination of light irradiation energy and photosensitizer dose, optimizing PDT to effectively kill target cells while minimizing side effects on normal cells, applicable to various diseases including leukemia, tumors, and other conditions.
Implementation Method 1
5-aminolevulinic acids (5-ALA) are oral absorbability and metabolized to protoporphyrin IX (PpIX) in the process of biosynthesis of heme in intracellular mitochondria
Implementation Method 2
PpIX is a photosensitizer that has an absorption band near 410 nm, called a Soret band, and an absorption band near 500 to 650 nm, called a Q band
Implementation Method 3
generates reactive oxygen species by irradiation with light having these absorption band wavelengths
Data Source
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AI summary
The invention is directed to a method for determining condition parameters for photodynamic therapy in which after administration of 5-aminolevulinic acids, protoporphyrin IX accumulated in cells is irradiated with light, the method including steps of: calculating, in an experimental phase, a regression curve representing a correlation among three condition parameters: cell viability (Y), intracellular protoporphyrin IX accumulation (X), and light irradiation energy density (P); and selecting in advance, prior to initiation of therapy, two condition parameters from the cell viability (Y), the intracellular protoporphyrin IX accumulation (X), and the light irradiation energy density (P), and then determining the remaining condition parameter using the regression curve. Thus, the photodynamic therapy can be optimized.