A Treatment Planning System for Pleural PDT.

Area of Science:

• Biomedical Engineering
• Medical Physics
• Oncology

Background:

• Uniform light distribution is crucial for effective photodynamic therapy (PDT), especially in complex anatomical spaces like the pleural cavity.
• Current methods using point sources for pleural PDT often result in uneven light fluence, potentially compromising treatment efficacy.
• Developing advanced dosimetry and treatment planning is essential for optimizing PDT delivery.

Purpose of the Study:

• To develop and evaluate a treatment planning system for improving light fluence uniformity in pleural photodynamic therapy.
• To investigate the correlation between simulated and measured light fluence rates within a chest phantom.
• To establish a clinical guideline tool for future pleural PDT procedures.

Main Methods:

• A treatment planning system was developed, incorporating an infrared camera to track a light source's movement within a chest phantom.
• Light fluence rate (mW/cm²) and cumulative fluence (J/cm²) were measured at seven sites using isotropic detectors.
• Light fluence was calculated using diffusion approximation with a finite-element model and validated against integrating sphere theory.

Main Results:

• The developed system demonstrated improved uniformity of light fluence rate distribution compared to traditional point source delivery.
• A strong correlation was established between calculated and measured light fluence rates, validating the treatment planning approach.
• The study successfully simulated light delivery in a pleural PDT scenario using a chest phantom.

Conclusions:

• The developed treatment planning system enhances light fluence uniformity for pleural photodynamic therapy.
• This system provides a valuable tool for in-vivo light dosimetry and clinical guidance in pleural PDT.
• Optimizing light delivery through advanced planning is critical for predictable and effective photodynamic therapy outcomes.