We have developed a laser-pulse mammograph capable of recording optical mammograms within ~3 min by measuring time-resolved transmittance at each of typically 1500 scan positions, 2.5 mm apart. As a first application two patients who have tumors were investigated successfully. From measured distributions of times of flight of photons corrected for edge effects we derived (1) characteristic quantities, such as photon counts in selected time windows, to generate optical mammograms; (2) effective transport scattering and absorption coefficients of breast tissue at each scan position, assuming the breast to be homogeneous; and (3) optical properties of a selected tumor by applying the theory of diffraction of photon density waves by spherical inhomogeneity. Mammograms recorded at different lateral offsets between source and detector fiber were used to estimate the depth of inhomogeneities.
© 1999 Optical Society of America
(170.3660) Medical optics and biotechnology : Light propagation in tissues
(170.5270) Medical optics and biotechnology : Photon density waves
(170.6920) Medical optics and biotechnology : Time-resolved imaging
Dirk Grosenick, Heidrun Wabnitz, Herbert H. Rinneberg, K. Thomas Moesta, and Peter M. Schlag, "Development of a Time-Domain Optical Mammograph and First in vivo Applications," Appl. Opt. 38, 2927-2943 (1999)