Experimental validation of a backpropagation algorithm forthree-dimensional breast tumor localization

摘要

To validate a new backpropagation algorithm for three-dimensionaln(3-D) tumor localization in breast tissue with a two-dimensionalnmeasurement, we performed experiments on breast phantoms using anheterodyne, frequency-domain photon migration system. The near-infraredn(680 or 780 nm) laser diode used to provide illumination was intensitynmodulated at both megahertz (20-60 MHz) and kilohertz (10 kHz)nfrequencies. The breast phantoms were made of plastic resin with anvariety of simulated tumors imbedded inside and then scanned with thensystem in a planar geometry. With megahertz modulation signals, both ofnthe amplitude and phase of the transmitted light were used in the datanreduction process, whereas with kilohertz modulation signals only thenamplitudes were used for the reconstruction. In both cases, thenbackpropagation reconstruction algorithm was used to accomplish 3-Dnlocalization of the imbedded tumors. In all cases, the reconstructednlocations for the hidden objects are in good agreement with the truenvalues. Our current work demonstrates the possibility and potential ofndeveloping low-cost optical tomographic instruments