An existing prototype of microwave imaging tomograph, previously designed by the present Authors for non destructive testing (NDT) applications, has been adapted in order to deal with biomedical targets. The developed system allows collecting multi-view multi-frequency data. An efficient inversion procedure is used to retrieve the distributions of the dielectric properties from the measured field samples. Some numerical simulations aimed at validating the proposed system and preliminary measurement results obtained by using a breast phantom are presented in this paper.