Systems for light application and dosimetry in photodynamic therapy

Area of Science:

• Biomedical Engineering
• Photodynamic Therapy
• Medical Devices

Background:

• Photodynamic therapy (PDT) efficacy relies on uniform light distribution and accurate dosimetry.
• Existing light delivery systems are often inadequate for irregularly shaped hollow organs.
• Precise light management is crucial for successful PDT outcomes.

Purpose of the Study:

• To develop and validate novel light delivery devices and dosimetry methods for PDT in hollow organs.
• To improve light homogeneity and enable on-line dosimetry for various anatomical sites.
• To address the challenges of treating multifocal superficial tumors in organs like the bladder.

Main Methods:

• Development of a catheter with an isotropic emitter, centered by a balloon for bladder PDT.
• Utilizing backscattered light from tissue for on-line dosimetry.
• Employing multiple backscattering from a white layer to homogenize light distribution.
• Computer simulations to validate the concept for non-spherical bladder shapes.
• Adaptation of devices for irradiation of larynx, bronchi, esophagus, and cervix.

Main Results:

• Demonstrated successful homogenization of light distribution using multiple backscattering.
• Validated the on-line dosimetry concept through computer simulations and experimental application.
• Showcased improved light homogeneity and dosimetry accuracy with the presented devices.
• Successfully applied adapted devices to various hollow organs, including the bladder, larynx, and cervix.

Conclusions:

• The developed devices significantly enhance light distribution homogeneity in PDT for hollow organs.
• The integrated on-line dosimetry system provides accurate real-time feedback for treatment monitoring.
• Multiple backscattering from a white layer is a promising technique for irregular geometries.
• These advancements offer improved efficacy and safety for PDT in challenging anatomical locations.