Light Density Index for Prostate Cancer Photodynamic Therapy Planning
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Solution Overview
Problem
Current photodynamic therapy for prostate cancer faces challenges in defining a treatment-effective light dose that varies among patients, requiring real-time adjustments during procedures and computational complexity, and lacks methods for predicting the efficacy of light delivery without causing collateral damage to surrounding tissues.
Innovation Solution
The introduction of a Light Density Index (LDI) calculated from historical data using the photosensitizing agent Palladium 3-oxo-15-methoxycarbonylmethyl-rhodobacteriochlorin 13-(2-sulfoethyl) amide (WST11), which predicts treatment efficacy and allows for prospective treatment planning by determining a treatment-effective threshold light dose, enabling more precise and effective light delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current treatment planning computational approaches are used to define light dose and fiber placement, then treatment effectiveness can be optimized, but the computational complexity precludes real-time intra-operative adjustment
Solution Approach 1:
The patent performs treatment planning computations before the actual treatment procedure. Treatment plans including fiber placement and light dose parameters are calculated in advance using computational models, then printed on templates that guide the actual procedure. This preliminary computation resolves the contradiction by providing optimized treatment parameters without requiring complex real-time calculations during the procedure.
2Reliability
If light dose is increased to ensure treatment effectiveness above threshold, then tumor treatment efficacy improves, but collateral damage to surrounding structures such as urethra and rectum increases
Solution Approach 1:
The patent uses treatment planning software to calculate and optimize light dose distribution at different locations within the prostate. The system determines specific light doses for different fiber placement positions and treatment volumes, ensuring that each region receives an appropriate dose that achieves tumor control while staying below thresholds that would cause damage to surrounding structures like the urethra and rectum.
Solution Approach 2:
The patent implements a treatment-effective threshold dose concept where light delivery is optimized to achieve just sufficient treatment effect. By calculating minimum effective doses through computational planning and using templates to guide precise fiber placement, the system delivers partial action (minimum effective dose rather than maximum possible dose) that achieves tumor control while minimizing collateral damage.
3Manufacturing precision
If treatment-effective threshold light dose is determined in advance for each patient, then treatment planning precision improves, but the variation in threshold dose among patients receiving the same photosensitizer and planning algorithm increases
Solution Approach 1:
The patent performs patient-specific treatment planning computations before treatment to determine individualized light dose thresholds. Each patient's treatment plan is customized based on their specific anatomy and treatment requirements, with the optimal light dose calculated in advance and printed on patient-specific templates. This preliminary patient-specific planning resolves the contradiction by providing precise, individualized treatment parameters without requiring real-time adjustment during the procedure.
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 LDI calculation validates treatment efficacy as early as 1 week post-treatment and confirms negative biopsies at 6 months, providing a calculable dose parameter that increases therapeutic success while reducing computational complexity and minimizing collateral damage.
Implementation Method 1
activating the photosensitizing agent by delivering light of appropriate wavelength through at least one optical fiber positioned proximal to the tumor
Implementation Method 2
photodynamic therapy (PDT) - in which a photosensitizing agent is administered systemically and is photoactivated locally to the tumor site
Data Source
AI summary
Improved methods of treating prostate cancer by vascular-targeted photodynamic therapy, and improved methods of planning treatment,are presented using a light density index to plan and guide effective treatment.