More than 10% of all women in the western world get breast cancer. High sensitivity to detect tumors with a size of 5mm and the use of non-ionising radiation are desirable to avoid the development of metastases. Ultrasound Computer Tomography (USCT) currently developed at KIT promises to be such a device. The USCT project requires precise simulation data of realistic breast models for the optimisation and further development. Up to now it was not possible to get such simulations within a time frame of roughly one day of computing time. The simulations presented in this work...