title: Subsurface diffuse optical tomography can localize absorber and fluorescent objects but recovered image sensitivity is nonlinear with depth.
abstract: Subsurface tomography with diffuse light has been investigated with a noncontact approach to characterize the performance of absorption and fluorescence imaging. Using both simulations and experiments, the reconstruction of local subsurface heterogeneity is demonstrated, but the recovery of target size and fluorophore concentration is not linear when changes in depth occur, whereas the mean position of the object for experimental fluorescent and absorber targets is accurate to within 0.5 and 1.45 mm when located within the first 10 mm below the surface. Improvements in the linearity of the response with depth appear to remain challenging and may ultimately limit the approach to detection rather than characterization applications. However, increases in tissue curvature and/or the addition of prior information are expected to improve the linearity of the response. The potential for this type of imaging technique to serve as a surgical guide is highlighted.
authors.affiliation: Thayer School of Engineering, Dartmouth College, New Hampshire 03755, USA. kepshire@dartmouth.edu
authors.forename: Dax S
authors.initials: DS
authors.lastname: Kepshire
authors.forename: Scott C
authors.initials: SC
authors.lastname: Davis
authors.forename: Hamid
authors.initials: H
authors.lastname: Dehghani
authors.forename: Keith D
authors.initials: KD
authors.lastname: Paulsen
authors.forename: Brian W
authors.initials: BW
authors.lastname: Pogue
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D008954:Models, Biological; D017711:Nonlinear Dynamics; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041622:Tomography, Optical / Q000295:instrumentation / Q000379:methods*