3D Ultrasound Computed Tomography (USCT) is an imaging method for early breast cancer detection. The third generation 3 USCT device is developed at Karlsruhe Institute of Technology. The USCT III device has a hemispherical transducer distribution and emits and receives nearly spherical waves. This enables reflection and transmission imaging simultaneously and fully in 3D. The main challenges for the front-end design are to integrate a large number of transducers, to allow high voltage coded excitation, and to receive low amplitude signals with high quality. These challenges were solved using a smart sensor frontend design with a custom application specific integrated circuit (ASIC).