An ultra wideband PN-radar for medical imaging applications is proposed. To detect water accumulation inside of the human body, e.g. the bladder, the radar signal undergoes multi-reflections and strong attenuation in human tissues. To fulfil the required high system dynamic range due to the signal attenuation in human tissues, a PN signal with order of 14 is used for the investigation. A demonstrator and a simulation model of a PN-radar are shown. The proposed PN-radar works with a chip rate of 2 GHz and therefore the signal is spread from 4 to 8 GHz after a mixer with LO frequency of 6 GHz. The influence of different SNRs and dispersion effects on the PN Signal are investigated. By comparing the PN-radar measurements with a Gauss pulse radar in a multiple targets scenario the proper function of the realized radar is demonstrated.