Evaluation of Light Fluence Distribution Using an IR Navigation System for HPPH-mediated Pleural Photodynamic Therapy...

Area of Science:

• Medical Physics
• Oncology
• Biophotonics

Background:

• Photodynamic therapy (PDT) requires uniform light distribution for predictable clinical outcomes.
• Current intrapleural PDT light delivery relies on point sources and isotropic detectors, posing challenges for uniformity assessment.
• Real-time monitoring of light source and treatment area geometry is crucial for optimizing PDT efficacy.

Purpose of the Study:

• To develop and evaluate a real-time infrared (IR) tracking camera system for intrapleural PDT.
• To assess the system's ability to monitor light source movement and treatment area contours.
• To quantify light distribution uniformity and its deviation from the prescribed dose during PDT.

Main Methods:

• Development of a real-time IR tracking camera system.
• Integration of a two-correction factor method and an empirical model for light fluence rate calculation.
• Clinical trial implementation to track light source position and treatment area surface.
• Comparison of calculated light fluence rates with isotropic detector measurements.

Main Results:

• Successful implementation of the IR navigation system in 75% of patients (15/20).
• Successful data analysis in 80% of implemented cases (12/15) due to detector location data.
• Demonstrated quantification of light distribution uniformity with a standard deviation of 18% from the prescribed dose.
• Identified system failure threshold at <30% of obtained light source positions.

Conclusions:

• An IR camera-based navigation system is feasible for tracking light source motion during intrapleural PDT.
• The system effectively quantifies light distribution uniformity, aiding in predictable PDT outcomes.
• System reliability depends on obtaining a sufficient percentage of light source positions during treatment.