About This Webinar
Time-resolved near-infrared spectroscopy (trNIRS) is an advanced tissue spectroscopy technique that permits noninvasive quantification of both absorption and scattering. Several studies have shown that measuring tissue absorption at dozens of wavelengths (i.e., hyperspectral NIRS) improves the accuracy of chromophores quantification. Therefore, a trNIRS system with hyperspectral capabilities would be very efficient for noninvasive monitoring of tissue chromophore content. Nevertheless, due to the complexity of time-resolved detection, very few attempts have been made to build hyperspectral trNIRS devices in either a lab or clinical setting. Diop’s team recently demonstrated that compressive sensing can be used to acquire trNIRS data over a wide spectral range without losing critical information. Although this was an important breakthrough, there were limitations, because the information reported by the hyperspectral compressive sensing time-resolved spectrometer only covered the spectral range between 710 and 830 nm. This range does not encompass the wavelengths necessary for reliable monitoring of tissue metabolism and blood oxygenation. The spectrometer also used a photomultiplier tube, which introduced significant afterpulsing that compromised the integrity of the late-photon data. Diop introduces the principle of hyperspectral compressive sensing trNIRS and discusses his team’s recent progress in extending the spectral range of the device, removing the afterpulsing, and improving the temporal resolution. He presents validation experiments in tissue-mimicking phantoms to demonstrate that the improved device can monitor dynamic blood oxygenation and metabolism.
***This presentation premiered during the 2022
BioPhotonics Conference. For more information on Photonics Media conferences, visit
events.photonics.com.
About the presenter
Mamadou Diop, Ph.D., is an assistant professor in the Department of Medical Biophysics and the School of Biomedical Engineering at Western University, where he leads the Translational Biophotonics Lab. He is also a scientist at the Lawson Health Research Institute, where he is a principal investigator of the Lawson Imaging Research Program. Diop earned bachelor’s and master’s degrees in physics from Dakar University and a doctorate in physics from the Centre for Optics, Photonics and Lasers at Laval University in Québec. His work as a postdoctoral fellow at the National Research Council of Canada involved optical trapping. His current research and teaching focus is on biophotonics with an emphasis on neuromonitoring using near-infrared spectroscopy and diffuse correlation spectroscopy.