Interstitial Photodynamic Therapy Light Control System

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Solution Overview

Problem

Current photodynamic therapy (PDT) systems face challenges in controlling and adjusting light delivery during interstitial tumor treatments, particularly due to limited light penetration and variations in tissue properties such as sensitizer concentration and oxygenation, leading to inconsistent treatment outcomes.

Innovation Solution

A system and method for real-time monitoring and adjustment of photodynamic therapy parameters, including fluence rate, sensitizer concentration, and tissue oxygenation, using optical fibers and a computer program to modify light delivery characteristics based on measured parameters, ensuring optimal light dose distribution and minimizing damage to healthy tissues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If interstitial PDT is used to treat deeper tumors, then treatment depth is improved, but light penetration remains limited

Engineering Contradiction:
Improvetreatment depthVSAvoidlight penetration
Core Design Contradiction:
Length of stationary objectVSIllumination intensity

Solution Approach 1:

The patent divides the treatment into multiple measurement and adjustment cycles, where the tissue volume is segmented into probed regions and the light delivery is divided into controllable portions that can be adjusted based on real-time feedback from different measurement points

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements real-time feedback by measuring photodynamic treatment parameters (such as light flux, sensitizer concentration, or tissue oxygenation) during treatment and using these measurements to adjust light delivery, ensuring optimal light penetration and treatment depth

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If multiple fibers are used to treat larger tumor volumes, then treatment coverage is improved, but system complexity increases

Engineering Contradiction:
Improvetreatment coverageVSAvoidsystem complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent makes the optical fibers multi-functional by enabling them to serve both as light delivery channels and as measurement probes. The same fibers used for illuminating the tumor can also detect photodynamic treatment parameters, reducing the need for separate measurement devices and simplifying the overall system

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the light delivery function and measurement function into a single integrated system where treatment and monitoring are performed simultaneously through the same optical fibers, reducing system complexity while maintaining comprehensive treatment coverage

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If fixed light dose is used for treatment, then treatment simplicity is improved, but treatment precision deteriorates

Engineering Contradiction:
Improvetreatment simplicityVSAvoidtreatment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent transitions from static fixed-dose treatment to dynamic adaptive treatment where light delivery parameters are continuously adjusted based on real-time measurements of photodynamic treatment parameters, allowing the system to adapt to actual tissue conditions while maintaining operational simplicity through automated control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the treatment parameter from a fixed predetermined dose to a dynamically adjusted dose based on measured parameters such as light flux, sensitizer concentration, or tissue oxygenation, enabling precise control of the photodynamic treatment effect

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If sequential probe operation is used for measurement, then measurement accuracy is improved, but treatment time increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidtreatment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements periodic measurement cycles where measurements are taken at regular intervals during treatment rather than continuously, allowing sufficient measurement accuracy while minimizing treatment time loss through optimized measurement timing and duration

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent maintains continuous light delivery while performing measurements by using the same optical fibers for both purposes simultaneously, eliminating interruptions in treatment and ensuring continuous therapeutic effect while obtaining accurate measurements

Inventive Principle:
Principle #20Continuity of useful action

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 more precise and effective PDT by adjusting light delivery in real-time, reducing variations in treatment outcomes and minimizing damage to healthy tissues, thereby improving patient safety and treatment efficacy.

Implementation Method 1

PDT relies on the use of a photosensitizer agent being activated by light in the presence of oxygen, leading to the production of toxic singlet oxygen radicals

Methodology Applied
Scientific EffectPhotodynamic therapy: Photosynthesis

Implementation Method 2

light-conducting optical fibers are brought into the tumor

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2298413B1System for controlling and adjusting interstitial photodynamic light therapy parameters
Publication Date: 2015.07.01 SPECTRACURE
  • EP2298413B1 patent drawingFigure 1
  • EP2298413B1 patent drawingFigure 2
  • EP2298413B1 patent drawingFigure 3a~4b

AI summary

A method and system for controlling and adjusting light in interstitial photodynamic light therapy (IPDT) in a subject is disclosed. More particularly, a method for controlling the light in interstitial tumor photodynamic light therapy is described using a calculation method for determination of status of tissue during the PDT treatment. The status is used in a feedback loop to control the continued PDT treatment. Methods are disclosed that constitute pre-treatment and realtime dosimetry modules for IPDT on the whole prostate glandular tissue. The method includes reconstruction of the target geometry, optimization of source fiber positions within this geometry, monitoring of the light attenuation during the treatment procedure and updating individual fiber irradiation times to take into account any variation in tissue light transmission. A control device that is arranged to restrict delivery of therapeutic light treatment at least temporary in dependence of at least one attribute of one of photodynamic treatment parameters. In comparison to no treatment feedback, a significant undertreatment of the patient as well as damage to healthy organs at risk are avoided.