Microlamp for in-situ tissue spectroscopy for the dosimetry of photodynamic therapy

Photodynamic therapy (PDT) is a growing treatment modality for various diseases, most notably cancer. It has several advantages compared to radiotherapy and chemotherapy, but a good dosimetry is very important for an efficient treatment. One of the key parameters in PDT dosimetry is oxygen availability in tissue, which can be measured making use of spectroscopic techniques. For this purpose, a broadband source is needed to illuminate the volume of interest at all wavelengths necessary for the spectroscopic information. In an implantable system under development, this broadband source is being implemented as a microfabricated lamp. In this paper we report on the characterisation of a tungsten microheater as the incandescent filament, showing that this type of element can be brought to emit significant radiation in the wavelength range of interest.