Nonparametric characterization of human breast tissue by the Laguerre expansion of the kernels technique applied on propagating femtosecond laser pulses through biopsy samples

Ultrafast laser pulses transmitted through excised human breast tissue have been detected by a streak camera. Experimental data of the temporal spread of the ultrafast pulse during the transmission through the tissue have bee n analyzed using the Laguerre expansion technique. This method treats the m edium of propagation as a "black box system" and using data sets of inciden t-transmitted pulse, it relates to this system a set of coefficients as wel l the first-order system kernels. This analysis could present an alternativ e method of tissue characterization when, due to the limited optical thickn ess of small biopsy samples, the photon diffusion approximation cannot be u sed successfully. (C) 1999 American Institute of Physics. [S0003-6951(99)04 805-6].