Parametric handheld optical probe (HOPE) for biological tissue characterization in the near-infrared spectral range

Various optical monitoring techniques across the visible and near-infrared spectral regions have been developed to assess tissue characteristics for a wide range of biomedical and health science applications. In this work, we designed a multimodal non-invasive optical probe that can provide information regarding live tissue metrics. The probe, 12 mm in diameter, consists of three separate small probes with different diameters. Each of the probes is sensitive to a different intrinsic tissue feature for diagnostic purposes. These features include diffuse light reflectance, scattering coefficient, refractive index, blood flow, and temperature. The probe apparatus is based on wideband light source and spectrometer, a laser Doppler flowmetry instrument, and a temperature-sensing device. The advantage of combining three different approaches in a single probe create a sensor able to characterize broad tissue metrics with high temporal resolution to better understand disease mechanisms. The performance of this hybrid handheld optical probe (HOPE) was tested in two models of tissue injury: (1) arterial occlusion of a human hand (n=3); and (2) brain hypoxia in mice (n=2). Following data analysis, differences in tissue parameters were observed compared to baseline measures. Experimental results illustrate the ability of the HOPE setup to monitor variations in different tissue parameters. This probe may serve as a sensor device for characterization of tissue features in a medical environment during clinical diagnosis and therapeutic procedures.