Assembly of a PDT device with a near-infrared fluorescence monitoring of PpIX during treatment

This paper describes the assembly and characterization of a system to treat and monitor ALA-based photodynamic therapy, using near-infrared fluorescence images for photosensitizer monitoring. The system is portable, user friendly and low cost, using a diode laser emitting at 633 nm as treatment light, capable to delivery up to 150 mW/cm2 at the lesion surface. The PpIX fluorescence is excited by the treatment light itself, and detected by camera in real-time. Since the excitation and emission wavelengths are in the red-NIR spectral regions, the penetration into the skin is improved and the volume measured by the fluorescence images is larger when compared to the widely used violet excitation.