title: Quantitative diffuse reflectance and fluorescence spectroscopy: tool to monitor tumor physiology in vivo.
abstract: This study demonstrates the use of optical spectroscopy for monitoring tumor oxygenation and metabolism in response to hyperoxic gas breathing. Hemoglobin saturation and redox ratio were quantified for a set of 14 and 9 mice, respectively, measured at baseline and during carbogen breathing (95% O(2), 5% CO(2)). In particular, significant increases in hemoglobin saturation and fluorescence redox ratio were observed upon carbogen breathing. These data were compared with data obtained concurrently using an established invasive technique, the OxyLite partial oxygen pressure (pO(2)) system, which also showed a significant increase in pO(2). It was found that the direction of changes were generally the same between all of the methods, but that the OxyLite system was much more variable in general, suggesting that optical techniques may provide a better assessment of global tumor physiology. Optical spectroscopy measurements are demonstrated to provide a reliable, reproducible indication of changes in tumor physiology in response to physiologic manipulation.
authors.affiliation: Duke University Medical Center, Department of Radiation Oncology, Box 3455, Durham, North Carolina 27710, USA. greg.palmer@duke.edu
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Palmer
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Viola
authors.forename: Thies
authors.initials: T
authors.lastname: Schroeder
authors.forename: Pavel S
authors.initials: PS
authors.lastname: Yarmolenko
authors.forename: Mark W
authors.initials: MW
authors.lastname: Dewhirst
authors.forename: Nirmala
authors.initials: N
authors.lastname: Ramanujam
mesh_terms: D000465:Algorithms; D000818:Animals; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism*; D051379:Mice; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D010783:Photometry / Q000379:methods*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D010100:Oxygen