This paper presents a synthetic aperture-based UWB radar imaging system. The goal is to detect the urine accumulation in the human bladder. To verify this radar concept a bladder model with various human tissues including realistic dielectric properties is simulated. Two scan configurations with different antenna positions are used to investigate the influence of the synthetic aperture length and position number in the microwave images. To generate the imaging results, Delay and Sum algorithm together with coherent weighting is applied. The achieved imaging results demonstrate the possibility of detecting the position and volume of urine in the human bladder and therefore the potential application of this radar imaging system in the clinics for diagnosis purposes.I.