Grid-Based Breast Cancer Screening and Epidemiology: the MammoGrid Project Breast cancer as a medical condition and mammograms as images exhibit many dimensions of variability across any population. Similarly, the way diagnostic systems are used by clinicians and maintained by technicians varies between imaging centres and breast screening programmes, as does the appearance of the mammograms generated. In general, the sensitivity and specificity of breast screening programmes is unacceptably poor. Studies of second screening opinion suggest that technological support offers the best chance forward. A geographically distributed database of histologically proven cases, both positive and negative, that reflects the spread of pathologies across the population would quickly become an essential evidence base for radiologists in screening programmes and also those in training. It would also be an invaluable tool for the epidemiologist who wishes to study the effects of, say, lifestyle and diet. Exploiting existing and emerging technologies, the aim of the MammoGrid project is to develop a Europe-wide database of mammograms that will be used to investigate important healthcare applications and to explore the potential of the grid to support effective co-working between healthcare professionals. In particular, the project aims to prove that grids infrastructures can be practically used for collaborative medical image analysis, especially to enable radiologists from geographically dispersed hospitals to share standardized mammograms, to compare diagnoses (with and without computer aided detection) and to perform sophisticated epidemiological studies across national boundaries. This leads to several technical issues, including the standardization of mammograms, design of an appropriate clinical workstation and distribution of data, images and clinician queries across a grid-based database while respecting patient confidentiality and security protocols. This talk will outline the approach taken in MammoGrid to connect radiologists across a Grid using an "information infrastructure", a DICOM-compliant object model residing in multiple, distributed data stores in Italy and the UK, and a service-based approach to managing a federation of grid-connected mammography databases. Tony Solomonides was formerly Head of Department and Associate Dean of Faculty at the University of the West of England, Bristol. Trained originally in Mathematics, he worked briefly in topology and its applications to non-linear mechanics before turning to Computer Science. He is now a Reader in Computer Science in the Centre for Complex Cooperative Systems at UWE and a CERN Associate. He has researched scientific databases and applications since the mid-1990's, having also worked in medical informatics, especially the management of diabetes and pathology of inflammatory bowel disease, before then. He has participated in the development and application of the CRISTAL database to track the construction of a Large Hadron Collider experiment at CERN. He has also written on the application of 'description-driven' methods and systems to the medical field, notably on large scale Electronic Patient Record, and on the tracking of antibiotic resistant bacteria in the community. He has also published extensively in the field of data collection through social survey instruments.