Optical Tomography Feedback Control for Photodynamic Therapy Dosimetry

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Solution Overview

Problem

Current photodynamic therapy (PDT) systems face challenges in addressing inter- and intra-patient variations in tissue absorption and scattering coefficients, leading to inadequate light distribution and treatment efficacy, which affects patient safety and treatment duration.

Innovation Solution

A PDT system incorporating a control unit, dosimetry unit, and optical diagnostic tomographic calculation unit that performs pre- and during-treatment measurements for real-time tomographic reconstruction of therapy parameters, using optical tomography to optimize light dosimetry and adjust treatment parameters based on individual patient data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional PDT systems are used without real-time monitoring, then the treatment procedure is simpler and faster to implement, but the light distribution becomes inadequate and treatment efficacy decreases due to inter- and intra-patient variations in tissue absorption and scattering coefficients

Engineering Contradiction:
Improvelight distribution precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system performs pre-treatment optical measurements and tomographic reconstruction to map tissue optical properties before light delivery. This preliminary characterization of absorption and scattering coefficients allows the treatment plan to be optimized in advance for each patient's specific tissue characteristics, ensuring precise light distribution from the outset.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements real-time feedback by continuously monitoring tissue optical properties during PDT treatment and dynamically adjusting light delivery parameters. The control unit receives updated optical property data from measurements taken during treatment and modifies illumination intensity and distribution accordingly, maintaining optimal light dosimetry despite tissue changes.

Inventive Principle:
Principle #23Feedback

2Reliability

If real-time tomographic reconstruction and feedback control are implemented, then patient safety improves and treatment precision increases, but the treatment time increases due to additional measurements and calculations

Engineering Contradiction:
Improvepatient safetyVSAvoidtreatment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs optical measurements and tomographic reconstructions continuously or at multiple stages during the treatment process rather than as separate pre- and post-treatment steps. This continuous monitoring and adjustment approach ensures patient safety is maintained throughout treatment without requiring lengthy interruptions, as the feedback control operates in real-time during light delivery.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs measurements at strategically selected time points during treatment (pre-treatment, during treatment, and post-treatment) rather than continuous measurements throughout. This partial sampling approach provides sufficient information for feedback control while minimizing the time overhead of measurements and calculations.

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If individualized treatment optimization is performed for each patient, then treatment efficacy improves, but the cost and complexity of the procedure increase

Engineering Contradiction:
Improvetreatment efficacyVSAvoidprocedure cost-effectiveness
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The system uses a multi-functional integrated platform that combines optical measurement capabilities, tomographic reconstruction algorithms, and feedback control in a single system. This universal device performs multiple functions (diagnostic imaging, treatment planning, real-time monitoring, and control) that would otherwise require separate systems, reducing overall procedural complexity and cost while maintaining individualized treatment optimization.

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

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 enhances patient safety by improving treatment precision and reducing treatment time while maintaining efficacy, allowing for more flexible and cost-effective PDT procedures.

Implementation Method 1

optical diagnostic tomographic calculation unit that performs pre- and during-treatment measurements for real-time tomographic reconstruction of therapy parameters

Methodology Applied
Scientific EffectOptical tomography: Tomography

Implementation Method 2

measurements of tissue in or at a subject for said PDT treatment based on at least one light source

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

Photodynamic therapy (PDT) is a cancer treatment modality that has shown promising results in terms of selectivity and efficacy

Methodology Applied
Scientific EffectPhotodynamic therapy: Photo-oxidation

Implementation Method 4

one aims to induce tissue damage in a tissue volume using interstitially placed optical light sources, such as optical fibers

Methodology Applied
Scientific EffectLight delivery: Light

Data Source

PatentEP2167192B1System for optical tomography feedback control of dosimetry for photodynamic therapy
Publication Date: 2018.11.07 SPECTRACURE
  • EP2167192B1 patent drawingFigure 1
  • EP2167192B1 patent drawingFigure 2a~2b
  • EP2167192B1 patent drawingFigure 3~4

AI summary

Control of interstitial photodynamic therapy (PDT) by means of modulation control and/or optical tomography are disclosed. Accurate reconstruction of optical properties in tissue treated by the PDT is provided. Optical tomography is used as an input for controlling dosimetry in said PDT system.