The relative transparency of biological materials to high-frequency electromagnetic waves has encouraged the development of new systems for imaging. This report describes experiments of microwave tomography conducted on a prototype. The object to be analyzed is submerged in water and is illuminated by a plane wave. The total electric field is analyzed by a microwave camera. The recorded data are then processed numerically in order to reconstruct the image that corresponds to the distribution of equivalent currents in a defined plane of a section. Experiments have been conducted on isolated kidneys with and without perfusion. The influence of the perfusing solution temperature has also been studied. These experiments show the potential of this system, especially through the correlation between microwave images and the biological structures. They also confirm previous results concerning spatial resolution and depth of exploration. Finally, the results demonstrate the influence of temperature and support the applicability of this imaging system in non-invasive thermometry, especially for clinical hyperthermia.