Abstract. The ability to quantitatively determine tissue fluorescence is of interest for the purpose of better understanding the details of photodynamic therapy of skin cancer. In particular, we are interested in quantifying protoporphyrin IX (PpIX) in vivo. We present a method of correcting fluorescence for effects of native tissue absorption and scattering properties in a spatially resolved manner that preserves the resolution of the fluorescence imaging system, based off a homogeneous representation of tissue. Validation was performed using a series of liquid turbid phantoms having varying concentrations of absorber, scatterer, and fluorophore (PpIX). Through the quantification of tissue optical properties via spatial frequency domain imaging, an empirical model based on Monte Carlo simulations was deployed to successfully decouple the effects of absorption and scattering from fluorescence. From this we were able to deduce the concentration of the PpIX to within 0.2 μg/ml of the known concentration. This method was subsequently applied to the determination of PpIX concentration from in vivo normal skin where the model-based correction determined a concentration of 1.6 μg/ml, which is in agreement with literature. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).
Abstract. The standard of care for clinical assessment of burn severity and extent lacks a quantitative measurement. In this work, spatial frequency domain imaging (SFDI) was used to measure 48 thermal burns of graded severity (superficial partial, deep partial, and full thickness) in a porcine model. Functional (total hemoglobin and tissue oxygen saturation) and structural parameters (tissue scattering) derived from the SFDI measurements were monitored over 72 h for each burn type and compared to gold standard histological measurements of burn depth. Tissue oxygen saturation (stO 2 ) and total hemoglobin (ctHbT) differentiated superficial partial thickness burns from more severe burn types after 2 and 72 h, respectively (p < 0.01), but were unable to differentiate deep partial from full thickness wounds in the first 72 h. Tissue scattering parameters separated superficial burns from all burn types immediately after injury (p < 0.01), and separated all three burn types from each other after 24 h (p < 0.01). Tissue scattering parameters also showed a strong negative correlation to histological burn depth as measured by vimentin immunostain (r 2 > 0.89). These results show promise for the use of SFDIderived tissue scattering as a correlation to burn depth and the potential to assess burn depth via a combination of SFDI functional and structural parameters. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
Spatial Frequency Domain Imaging (SFDI) is a non-contact imaging method that uses multiple frequency spatial illumination to generate two dimensional maps of tissue optical properties (absorption and reduced scattering) and chromophore concentrations. We present phantom validation and pilot clinical data of a deployed light-emitting diode (LED) based system. The system employs four LED wavelengths (658 nm, 730 nm, 850 nm, 970 nm) to quantitatively assess tissue health by measurement of common tissue constituents. Phantom validation results and maps of oxyhemoglobin, deoxy-hemoglobin, water content, reduced scattering, and surface topography will be presented for pilot studies assessing burn severity and efficacy of port wine stain treatment.
This work presents an electro-optical multispectral capability that detects and monitors marine mammals. It is a continuance of Whale Search Radar SBIR program funded by PMA-264 through NAVAIR. A lightweight, multispectral, turreted imaging system is designed for airborne and ship based platforms to detect and monitor marine mammals. The system tests were conducted over the Humpback whale breeding and calving area in Maui, Hawaii. The results of the tests and the system description are presented. The development of an automatic whale detection algorithm is discussed as well as methodology used to turn raw survey data into quantifiable data products.
Advanced Coherent Technologies, LLC has demonstrated the use of multi-channel imaging systems in a variety of applications. These systems are composed of multiple cameras or 'channels', each of which can be coupled with spectral filters, polarization analyzers, or unique optics (e.g. for field of view (FOV) or aperture adjustments). The channel content is designed specifically for the extraction of information and/or the detection of targets. Airborne data collects have been made over forest and maritime environments for the detection of various targets. The results of these collects are discussed and analyzed. Of particular concern is how channel content is chosen in each environment and for each target.
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