A telemetric light delivery system for metronomic photodynamic therapy (mPDT) in rats

Light delivery and monitoring during photodynamic therapy (PDT) is often limited by the need for a physical link between the light source, detectors and the treatment volume. This paper reports on the first in vivo experiments performed with a fully implantable telemetric system, designed for a rat glioblastoma model. In this system, light delivery is performed using a solid state optode containing 2 LEDs, and 4 photodiodes which will be used to monitor light delivery in future experiments. Powering and communication is achieved by means of an inductive link. The implant may remain in the animal for extended time periods, making it particularly interesting for performing metronomic PDT. In this paper, we demonstrate the feasibility of in vivo light delivery and biocompatibility of the device.. Activation of the inductive link as well as illumination of the brain by the LED did not influence animal behavior during or after treatment. We show that the implant can remain in the animal for two weeks without causing serious biological reactions.