Early and accurate diagnosis of breast cancer in women is a pending challenge. Digital x-ray mammography is considered today’s state of the art in diagnosis although severe insufficiencies are acknowledged. Conventional film-screen mammography, digital tomosynthesis, ultrasound, nuclear medicine and magnetic resonance imaging are also in use or under investigation. There is a general consensus that 3D imaging could offer significant advantages. Dedicated x-ray computed tomography (CT) of the female breast without exposure of the body trunk appears to be a further candidate with improved diagnostic capabilities, but radiation protection issues have to be solved. In consequence, this project focuses on the development of a dedicated scanner using novel technology and optimisation strategies. We intend to prove the feasibility of CT of the breast with very high spatial resolution of 100 µm or better and high soft-tissue differentiation at dose levels equal to or below those of two-view digital mammography. First simulation studies support the concept. To allow for balanced conclusions on justification of practice and risk assessment, the performance of breast CT will be validated and compared against digital mammography and tomosynthesis primarily, but also against any other novel approach. To achieve the proposed goals three European scientific institutes of international reputation and two manufactures with the respective know-how have formed a consortium. The necessary equipment, tools, test and measurement approaches are available; new multi-modality tests have to be developed for a meaningful comparison of 2D and 3D imaging. It is our intention to provide proofs of concept and results on breast CT in the relatively short time span of 30 months. Pending on the results of the project outlined here, a multimodality clinical study with an extended European consortium is planned as a follow-up.