Interstitial Photodynamic Light Therapy System with Real-Time Dosimetry

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Solution Overview

Problem

Current light therapy techniques face challenges in ensuring accurate delivery of photodynamic therapy due to photobleaching of photosensitizers and changes in tissue optical properties, which complicates the measurement of photosensitizer concentration and radiant exposure, leading to inefficiencies in tumor illumination.

Innovation Solution

A system comprising light-transmitting catheters with treatment and dosimetry fibers, where light received at the dosimetry fibers is measured using a spectrometer to determine photosensitizer properties, allowing for real-time adjustment of the treatment plan and updated light dosing to ensure complete tumor illumination while minimizing exposure to surrounding tissue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If photodynamic therapy is administered to treat tissue, then therapeutic effect is achieved, but measurement precision of photosensitizer concentration and radiant exposure deteriorates due to photobleaching and tissue optical property changes

Engineering Contradiction:
Improvetherapeutic effectVSAvoidphotosensitizer concentration and radiant exposure measurement
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary measurement of photosensitizer concentration and tissue optical properties before light delivery begins. This preliminary action establishes baseline values that can be used for accurate dose calculation even as photobleaching occurs during treatment, resolving the measurement precision problem while maintaining therapeutic reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors photosensitizer concentration and tissue optical properties during photodynamic therapy using fluorescence measurements and light transmission through the tissue. This feedback mechanism allows real-time adjustment of treatment parameters to compensate for photobleaching and maintain accurate dosimetry throughout the therapy process

Inventive Principle:
Principle #23Feedback

2Reliability

If entire tumor is illuminated with sufficient dose light to ensure successful treatment, then treatment efficacy is improved, but exposure of surrounding healthy tissue increases

Engineering Contradiction:
Improvetreatment efficacyVSAvoidexposure of surrounding healthy tissue
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system uses optical property mapping to identify regions within the tumor with different photosensitizer concentrations and optical characteristics. Treatment parameters are then locally adjusted to deliver appropriate doses to each region, ensuring complete tumor illumination while minimizing exposure to surrounding healthy tissue through spatially selective treatment

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts treatment parameters including light intensity, wavelength, and delivery duration based on real-time measurements of photosensitizer concentration and tissue optical properties. This dynamic adaptation allows optimization of light delivery to match the actual distribution of photosensitizer in the tumor, improving treatment efficacy while reducing unnecessary exposure to healthy tissues

Inventive Principle:
Principle #15Dynamics

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 enables precise and efficient delivery of therapeutic light to tumors, improving the accuracy of photodynamic therapy by allowing for real-time modification of treatment plans based on measured tissue properties, thereby enhancing treatment efficacy and minimizing side effects.

Implementation Method 1

ILT can be combined with prior administration of light sensitive medicine (i.e., photosensitizer) that absorbs the therapeutic light and interacts with surrounding tissue constituents (e.g., oxygen) to generate reactive species that can destroy the target tissue

Methodology Applied
Scientific EffectPhotodynamic therapy: Photosynthesis

Implementation Method 2

the energy of the light can be absorbed by blood or external additives (such as metal particles) that convert the light energy into heat, to induce complete destruction of the target tissue

Methodology Applied
Scientific EffectPhotothermal conversion: Absorption (EM radiation)

Implementation Method 3

Light received at the dosimetry fiber is measured using a spectrometer in operable communication with the dosimetry fiber

Methodology Applied
Scientific EffectSpectroscopy: Absorption Spectroscopy

Implementation Method 4

Photofrin and other photodynamic sensitizers can be degraded by light exposure, a process called photobleaching, and this can be measured by loss of photosensitizer characteristic fluorescence

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3325096B1System for delivering dosed light to tissue
Publication Date: 2023.09.06 HEALTH RESEARCH INC
  • EP3325096B1 patent drawingFigure 1~2
  • EP3325096B1 patent drawingFigure 3~4
  • EP3325096B1 patent drawingFigure 5~6

AI summary

A system and method for interstitial photodynamic light therapy (I-PDT) of a tissue. A plurality of light-transmitting catheters (LTCs) are provided and placed in the tissue according to a pre-determined treatment plan, wherein an LTC includes a first treatment fiber disposed therethrough, and an LTC includes a dosimetry fiber disposed therethrough. A dose light is provided to the tissue by way of the first treatment fiber according to the pre-determined treatment plan. Light received at the dosimetry fiber is measured using a spectrometer in operable communication with the dosimetry fiber. One or more properties of a photosensitizer in the tissue are determined. The treatment plan is modified based on the properties of the photosensitizer, and an updated dose light is provided to the tissue by way of the first treatment fiber according to the modified treatment plan.