A light blanket for intraoperative photodynamic therapy

Area of Science:

• Biomedical Engineering
• Medical Physics
• Oncology

Background:

• Photodynamic therapy (PDT) for malignant pleural and intraperitoneal diseases traditionally uses hand-held point sources.
• Current methods can lead to uneven light distribution and prolonged operating times.
• There is a need for improved light delivery systems in intraoperative PDT.

Purpose of the Study:

• To design and evaluate a novel light blanket as a substitute for point sources in PDT.
• To assess the uniformity and efficiency of light distribution from the light blanket.
• To explore its potential for intraoperative and superficial PDT applications.

Main Methods:

• A light blanket composed of parallel cylindrical diffusing fibers (CDFs) was designed.
• Experiments involved a 9cmx9cm blanket with 8 CDFs, using intralipid as a scattering medium and aluminum foil for shielding.
• Light distribution was measured using an isotropic detector and motorized platform in air, with intralipid, and in a tissue mimic phantom.

Main Results:

• The light blanket achieved a full width at half maximum of 7.9-8.1 cm, indicating good lateral coverage.
• Average fluence rates per input power ranged from 7.4 to 20.0 mW/cm²/W across different conditions.
• Standard deviations for fluence rate were low (1.1-2.6 mW/cm²/W), demonstrating reasonable uniformity.

Conclusions:

• The light blanket design provides a uniform light field for effective coverage in intraoperative PDT.
• Its flexibility allows adaptation to anatomical structures.
• The system shows significant potential for clinical use in both intraoperative and superficial PDT treatments.