  We propose an innovative fast-cycling accelerator complex conceived and
designed to exploit at best the properties of accelerated ion beams for
hadrontherapy. A cyclinac is composed by a cyclotron, which can be used also
for other valuable medical and research purposes, followed by a high gradient
linear accelerator capable to produce ion beams optimized for the irradiation
of solid tumours with the most modern techniques. The properties of cyclinacs
together with design studies for protons and carbon ions are presented and the
advantages in facing the challenges of hadrontherapy are discussed.
