Interstitial PDT Fluence Control via Temperature Feedback
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Solution Overview
Problem
Current interstitial photodynamic therapy (I-PDT) with porfimer sodium has a limited cure rate and lacks systematic evaluation of tissue heating, with clinically approved light dose rates chosen arbitrarily, potentially limiting treatment efficacy due to high dose rates that may deplete tumor oxygen levels and induce significant thermal ablation.
Innovation Solution
A method and system for I-PDT that involves administering a photosensitizer and using optical fibers to deliver treatment light, with real-time temperature measurement and adjustment of fluence rate to maintain tissue temperatures between 50° C. and 90° C., allowing for controlled photothermal ablation to enhance treatment efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high dose rate light (400 mW/cm²) is applied for I-PDT with porfimer sodium, then treatment time is shortened, but tissue temperature increases causing thermal ablation and oxygen depletion
Solution Approach 1:
The patent applies dynamic control by continuously monitoring tissue temperature during light delivery and adjusting the fluence rate in real-time. The system transitions from static, fixed-dose-rate illumination to dynamic modulation where the light dose rate is adjusted based on measured temperature feedback, allowing optimization of both treatment speed and temperature control
Solution Approach 2:
The patent changes the operating parameters of light delivery by modifying the fluence rate based on temperature measurements. The system implements parameter adaptation where the light dose rate (mW/cm²) is dynamically adjusted according to the measured tissue temperature, enabling operation in different temperature regimes to achieve desired therapeutic outcomes while preventing excessive thermal ablation
2Loss of time
If high dose rate light is applied to shorten treatment time, then treatment duration is reduced, but cure rate is limited due to oxygen depletion
Solution Approach 1:
The patent implements periodic or pulsed light delivery patterns where illumination is delivered in cycles with periods of light delivery followed by periods of reduced or zero illumination. This allows tissue oxygen levels to recover during dark periods while still delivering cumulative photodynamic dose, thereby maintaining cure rate while managing treatment duration
Solution Approach 2:
The system dynamically adjusts light delivery parameters during treatment based on real-time temperature and oxygen level monitoring, transitioning from static high-dose-rate illumination to adaptive dosing that maintains therapeutic effectiveness while preventing oxygen depletion-related treatment failure
3Productivity
If fluence rate is increased to improve treatment efficiency, then productivity increases, but harmful thermal effects increase
Solution Approach 1:
The patent implements a feedback control system where tissue temperature is continuously monitored during light delivery and the measured temperature is fed back to the light delivery system. This feedback loop enables automatic adjustment of fluence rate to maintain temperature within therapeutic boundaries, preventing harmful thermal ablation while preserving treatment efficiency
Solution Approach 2:
The system dynamically modulates fluence rate based on real-time temperature feedback, transitioning from static high-intensity illumination to adaptive light delivery that responds to tissue thermal conditions, thereby maintaining treatment efficiency while preventing harmful thermal effects
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 approach significantly enhances the cure rate of I-PDT by optimizing tissue temperature, achieving a 70% cure rate in mouse models compared to 40% without thermal ablation, while maintaining safe and effective light doses.
Implementation Method 1
concurrent photothermal ablation and interstitial photodynamic therapy
Implementation Method 2
A temperature sensor is configured to measure a temperature of the tissue
Implementation Method 3
A treatment light is applied to the tissue by way of the one or more optical fibers
Data Source
AI summary
The present disclosure provides a method and a system for treating a tissue using photodynamic therapy (PDT). A photosensitizer is administered to the tissue and one or more optical fibers are placed in the tissue. A treatment light is applied to the tissue by way of the one or more optical fibers. A temperature of the tissue is measured during application of the treatment light, and a fluence rate of the treatment light is modified based on the temperature of the tissue. For example, the fluence rate may be modified to be lower if the temperature of the tissue is higher than a predetermined threshold.