Light dosimetry and dose verification for pleural PDT

Area of Science:

• Oncology
• Biomedical Engineering
• Photomedicine

Background:

• Photodynamic therapy (PDT) efficacy relies on precise light dosimetry.
• Accurate light delivery monitoring is essential for predicting PDT outcomes in patients.
• Previous methods did not fully account for direct and scattered light within the pleural cavity.

Purpose of the Study:

• To develop and validate an improved method for in-vivo light dosimetry in patients undergoing photodynamic therapy.
• To enhance the accuracy of light fluence calculations within the pleural cavity for non-small cell lung cancer treatment.
• To establish a clinical guideline for future pleural PDT treatments based on precise light dosimetry.

Main Methods:

• Phase I clinical trial involving HPPH-mediated PDT for non-small cell lung cancer with pleural effusion.
• Real-time monitoring of fluence rate and cumulative fluence using isotropic detectors at multiple sites.
• Utilized a real-time infrared navigation system to differentiate direct and scattered light.
• Developed an improved theoretical model for light fluence calculation in elliptical geometries, validated with phantom and patient data.

Main Results:

• Established a method to accurately calculate total light fluence at the cavity wall.
• The improved model accounts for light source location, cavity geometry, and optical properties.
• Calculated light fluence correlated well with measured fluence across diverse patient cavity geometries.

Conclusions:

• The developed dosimetry method provides a more accurate assessment of light delivery in pleural PDT.
• This approach can be integrated into clinical practice to optimize PDT treatment parameters.
• Results offer a foundation for a clinical guideline to improve future pleural PDT efficacy and patient outcomes.