"The greatest challenge for radiation therapy is to reach the highest probability of cure with the least morbidity. In practice, some difficulties remain to identify cancer cells, target them with radiation and minimize collateral damage. Over the last decades, remarkable progress has been made thanks to modern advances in computer and imaging technologies. Currently, the radiotherapy has reached a point where, besides 3D tumour morphology, time variations and biological variability within the tumour can also be taken into account. The ""SUMMER"" project is devised to produce unique software using several imaging sources (CT, MRI, PET, MR spectroscopy, fMRI, 4D PET-CT) for biological target volume delineation, based on spatial co-registration of multimodal morphologic and functional images. Furthermore, it will make additional biological information concerning tumour extension and tumour response available to radiotherapy, essential for patient treatment follow-up. Finally, radiation area will be more focused leading to less side-effect for the patient.Radiation oncology is now more dependent on medical imaging than it has ever been - and that dependence is only going to become greater. Therefore, convergence and collaboration of radiation oncology, nuclear medicine, diagnostic imaging and also computer science is the underlying driver to integrate efficiently and cost-effectively all information coming from various imaging technologies into the radiation therapy workflow. The design challenge is to combine the different level and kind of information into one interface, while currently doctors need to mentally do this operation. ""SUMMER"" will contribute to renew and strengthen this relationship through cross-disciplinary research, common workshops, and collaboration on training and education."