title: Nonlinear reconstruction of absorption and fluorescence contrast from measured diffuse transmittance and reflectance of a compressed-breast-simulating phantom.
abstract: We report on the nonlinear reconstruction of local absorption and fluorescence contrast in tissuelike scattering media from measured time-domain diffuse reflectance and transmittance of laser as well as laser-excited fluorescence radiation. Measurements were taken at selected source-detector offsets using slablike diffusely scattering and fluorescent phantoms containing fluorescent heterogeneities. Such measurements simulate in vivo data that would be obtained employing a scanning, time-domain fluorescence mammograph, where the breast is gently compressed between two parallel glass plates, and source and detector optical fibers scan synchronously at various source-detector offsets, allowing the recording of laser and fluorescence mammograms. The diffusion equations modeling the propagation of the laser and fluorescence radiation were solved in frequency domain by the finite element method simultaneously for several modulation frequencies using Fourier transformation and preprocessed experimental data. To reconstruct the concentration of the fluorescent contrast agent, the Born approximation including higher-order reconstructed photon densities at the excitation wavelength was used. Axial resolution was determined that can be achieved by various detection schemes. We show that remission measurements increase the depth resolution significantly.
authors.affiliation: Philips Research Europe-Hamburg, Röntgenstrasse 24, 22335 Hamburg, Germany.
authors.forename: Ronny
authors.initials: R
authors.lastname: Ziegler
authors.forename: Tim
authors.initials: T
authors.lastname: Nielsen
authors.forename: Thomas
authors.initials: T
authors.lastname: Koehler
authors.forename: Dirk
authors.initials: D
authors.lastname: Grosenick
authors.forename: Oliver
authors.initials: O
authors.lastname: Steinkellner
authors.forename: Axel
authors.initials: A
authors.lastname: Hagen
authors.forename: Rainer
authors.initials: R
authors.lastname: Macdonald
authors.forename: Herbert
authors.initials: H
authors.lastname: Rinneberg
mesh_terms: D000465:Algorithms; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D005453:Fluorescence; D005456:Fluorescent Dyes; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D017711:Nonlinear Dynamics; D055620:Optical Phenomena; D019047:Phantoms, Imaging / Q000706:statistics & numerical data*; D041622:Tomography, Optical / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D003287:Contrast Media; D005456:Fluorescent Dyes