Using the microwave imaging technique for mammographic imaging is an interesting application and a growing research field. Compared to X-ray mammography there is potentially a significant benefit in using microwaves in the diagnosis of breast cancer tumours due to the high contrast in the dielectric properties between tumour and surrounding tissue.In this paper a tomographic microwave imaging ex- periment using transient time domain field data for the reconstruction process. A 2D iterative gradient based al- gorithm based on the FDTD-method (Finite Difference Time Domain-method), is used for the image reconstruction. The reconstructions have been performed using air as the background medium. To simulate more tissue like conditions the antennas have also been immersed in water and different objects immersed in the water have been imaged. Two different antenna models in the computations have also been tested. The results are promising and encourages further research on this method