Tetherless fiber-coupled optical sources for extended metronomic photodynamic therapy
1Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto M5G 2M9, Canada.
Background:
Metronomic photodynamic therapy (mPDT) involves the delivery of a low fluence rate of light and photosensitizing drug, continuously and over an extended period. However, in mPDT trials, there has been a perceived need for light sources that can deliver light reliably for extended periods, while being small enough to be tolerated by small animals.
Methods:
We report on the development of tetherless, lightweight, fiber-coupled optical sources for in vivo delivery of interstitial mPDT. Two forms are reported, based on diode lasers and light-emitting diodes (LEDs), the latter types weighing only 16.5g.
Results:
The prototypes have been well tolerated in preliminary trials on tumor-bearing rat models and can currently provide stable levels of performance for upwards of 5 days. We also report an extension of the concept to units coupled to several optical fibers to enable simultaneous irradiation of multiple locations in tissue.
Conclusion:
These prototypes fulfill a current need for reliable mPDT optical sources for use with animal models. They also serve as the foundation for the development of fiber-coupled sources for use in future clinical trials.
