In this work the active tomographic imaging of biological bodies which exhibits a high dielectric contrast is studied. Two approaches based on the Born approximation are presented: a differential reconstruction method which allows to visualize dielectric alterations and a matched synthesis method intended to minimize the distortion suffered by the illuminating field within the body. The presented techniques have been investigated by numerical simulations and experimentally in a cylindrical tomographic microwave system recently developed, considering the possible applications like Hyperthermia treatment monitoring in cancer.