PDT System with Shape Sensing for Precise Light Dose Control
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Solution Overview
Problem
Current photodynamic therapy (PDT) systems face challenges in precisely controlling the light dose administration during treatment, leading to potential damage of connective tissue or incomplete tumor cell destruction due to inadequate light distribution.
Innovation Solution
A PDT system comprising a bundle of optical fibers with distributed ends for precise light emission, an optical shape sensing fiber for tracking position and orientation, and a control algorithm that generates individually controllable light outputs based on real-time anatomical imaging and light diffusion models to optimize light distribution within the tumor while minimizing damage to connective tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If too much light is administered during PDT treatment, then tumor cell destruction is improved, but connective tissue damage occurs
Solution Approach 1:
The patent applies local quality by distributing light through multiple individual optical fibers positioned at different locations within the interventional device. Each fiber can be independently controlled to deliver light to specific spatial zones, enabling selective illumination of tumor regions while avoiding excessive light exposure to surrounding connective tissue. The system adjusts light intensity and distribution patterns locally based on real-time position feedback from shape sensing fibers.
Solution Approach 2:
The system implements dynamics by continuously monitoring the position and orientation of the interventional device using optical shape sensing fibers with distributed Bragg gratings. This real-time positional data feeds into a control algorithm that dynamically adjusts the light dose distribution among multiple optical fibers. The adaptive control enables the system to respond to changing anatomical conditions and device positioning, optimizing light delivery to maximize tumor destruction while minimizing connective tissue damage throughout the treatment process.
2Object-affected harmful factors
If too little light is administered during PDT treatment, then connective tissue is preserved, but tumor cells remain unaffected
Solution Approach 1:
The system ensures adequate light delivery to tumor regions by independently controlling multiple optical fibers positioned throughout the interventional device. The control algorithm calculates optimal light intensity for each fiber based on its spatial position relative to the tumor, ensuring that sufficient light reaches all tumor cells while maintaining connective tissue preservation in non-target areas. This localized light delivery approach eliminates the need to compromise between overall light dose and tissue protection.
Solution Approach 2:
The system employs feedback control by continuously monitoring the interventional device position using optical shape sensing fibers and using this information to adjust light distribution in real-time. The control algorithm receives positional feedback and dynamically optimizes the light dose delivered by each optical fiber, ensuring adequate illumination of tumor regions while preventing overexposure of connective tissue. This closed-loop control enables precise light dosing that adapts to actual treatment conditions.
3Device complexity
If a single optical fiber is used for light delivery, then device simplicity is maintained, but light distribution control precision is insufficient
Solution Approach 1:
The patent applies segmentation by dividing the light delivery function across multiple individual optical fibers instead of using a single fiber. Each fiber acts as an independent light delivery channel that can be controlled separately, enabling precise spatial distribution of light within the tumor. The bundle of fibers is integrated into a single interventional device structure, maintaining relative simplicity while achieving superior light distribution control through the coordinated action of multiple segmented light delivery elements.
Solution Approach 2:
The system implements multi-functionality by integrating multiple functions into the interventional device: a bundle of optical fibers for light delivery, optical shape sensing fibers with distributed Bragg gratings for position and orientation sensing, and a control system for coordinated operation. This multi-functional integration enables the single device to simultaneously perform light delivery, positional monitoring, and adaptive control, achieving precise light distribution control without requiring multiple separate devices.
4Ease of operation
If light dose is not precisely controlled during PDT, then treatment flexibility is maintained, but treatment outcome reliability deteriorates
Solution Approach 1:
The system employs feedback control by continuously monitoring the interventional device position using optical shape sensing fibers and using this information to adjust light distribution in real-time. The control algorithm receives positional feedback and dynamically optimizes the light dose delivered by each optical fiber, ensuring adequate illumination of tumor regions while preventing overexposure of connective tissue. This closed-loop control enables precise light dosing that adapts to actual treatment conditions.
Solution Approach 2:
The system implements dynamics by continuously monitoring the position and orientation of the interventional device using optical shape sensing fibers with distributed Bragg gratings. This real-time positional data feeds into a control algorithm that dynamically adjusts the light dose distribution among multiple optical fibers. The adaptive control enables the system to respond to changing anatomical conditions and device positioning, optimizing light delivery to maximize tumor destruction while minimizing connective tissue damage throughout the treatment process.
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
Enables precise and efficient light delivery directly to the tumor, maximizing treatment effectiveness while sparing surrounding tissue, applicable for various cancer types including prostate, breast, lung, and cervical cancers.
Implementation Method 1
Optical fibers with Fiber Bragg Gratings are used to determine a degree of flexure in the optical fibers
Implementation Method 2
an optical measurement applied to the optical shape sensing fiber
Implementation Method 3
a bundle of a plurality of optical fibers with distributed fibers ends forming respective light exit ports arranged to emit light
Implementation Method 4
The light excites the photosensitizer molecules to become active radicals through the formation of negatively charged singlet oxygen that kills the tumor cells
Data Source
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Figure 3a~3c
AI summary
A Photodynamic Therapy (PDT) system with an elongated interventional device (IDV) with a bundle of optical fibers (F1, F2, F3) forming respective light exit ports which can be individually accessed. The bundle has an optical shape sensing fiber (OSS), e.g. including Fiber Bragg Gratings, arranged for sensing position and orientation (P_O) of the light exit ports. A processor executes a control algorithm which generate a light dose signal (LDS) to allow generation of light outputs (LD1, LD2, LD3) to the plurality of optical fibers (F1, F2, F3) accordingly. The control algorithm generates the light dose signal (LDS) in response to the determined position and orientation of the light exit ports (P_O), and three- dimensional body anatomy image information obtained by a first image modality (I1), e.g. X- ray, MRI, CT, ultrasound, or PET-CT. This combination allows precise application of a light dose distribution for PDT treatment of a tumor with a minimal destruction of connective tissue. In embodiments, the control algorithm takes image information regarding distribution of a photosensitizer in the body tissue (I2) as input. The control algorithm may further take into account image information regarding a concentration of oxygen in the body tissue (I3). Both of such inputs allow a more precise PDT light application.