title: Determination of optical properties by interstitial white light spectroscopy using a custom fiber optic probe.
abstract: We demonstrate interstitial recovery of absorption and scattering coefficients using a custom optical probe and a Monte Carlo (MC)-based recovery algorithm. The probe consists of six side-firing spectroscopy fibers contained in a 1.1-mm outer diameter cladding, with each fiber having a different axial and angular position on the probe. Broadband white light is delivered by one of the fibers and is detected steady-state by the remaining fibers. These spatially and spectrally resolved data are analyzed using a MC-based fitting algorithm in order to extract the local optical properties. The technique was verified in tissue-simulating phantoms consisting of Intralipid-20% as a scatterer and either manganese meso-tetra (4-sulfanatophenyl) porphine or intact human erythrocytes as an absorber. Absorption coefficients were recovered with a mean error of 9% and scattering coefficients were recovered with a mean error of 19%, whereas the hemoglobin oxygen saturation was recovered with a mean error of 12%. These results demonstrate the feasibility of optical property recovery for situations in which surface-contact spectroscopy is not a possibility, and where only a single probe can be inserted into the tissue.
authors.affiliation: University of Rochester Medical Center, Department of Imaging Sciences, Rochester, New York 14642.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Baran
authors.forename: Michael C
authors.initials: MC
authors.lastname: Fenn
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Foster
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004912:Erythrocytes / Q000737:chemistry; D005336:Fiber Optic Technology / Q000295:instrumentation*; D006801:Humans; D009010:Monte Carlo Method; D055100:Optical Fibers; D010108:Oxyhemoglobins / Q000737:chemistry; D019047:Phantoms, Imaging; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods*
chemical_list: D010108:Oxyhemoglobins