CW Fluorescence imaging of tissue-like media in reflectance geometry

CARBONE, NICOLÁS ABEL; IRIARTE, D. I.; POMARICO, D. A.; GROSENICK, DIRK; MACDONALD, RAINER

Munich

Congreso; European Conferences on Biomedical Optics 2015; 2015

SPIE/OSA

Tissue imaging using radiation in the infrared region (NIR) has gained interest in the last years. Light interacts with biological tissues by events of absorption and scattering. In the NIR region, scattering strongly dominates over absorption, and because of this, tissue behaves as a turbid medium which can be characterized by two basic optical parameters, namely absorption (μa) and scattering coefficient (μs ). This behaviour imposes severe restrictions in recovering structural information; however it has also a number of advantages that makes imaging through NIR radiation an excellent technique as a complement of traditional modalities [1]. Among them, different kinds of tissues and or lesions can be distinguished by their different values of the optical parameters [2]. Besides, the radiation in this spectral zone is completely harmless allowing its frequent utilization for continuous monitoring. This imaging techinque can be improved by the use of fluorescent markers like indocyanine green (ICG) [3]. Different studies show that the pharmacokinetics of ICG is different in healthy tissues and in malignant lesions, allowing the observation of lesions by temporal discrimination of fluorescence [4]. We present experimental results and simulations of CW imaging of turbid media phantoms with inclusions emulating lesions. Both, bulk and inclusion, contain realistic concentrations of absorber and ICG. The aim is to localize the inclusion by analysis of both, absorption and fluorescence data.