A Medical Linac for Affordable Proton Therapy

Proton Therapy (PT) was first proposed in the 1940s. Application of this knowledge was largely led over the next fifty years by accelerator laboratories, but now also by commercial companies. Availability of PT is increasing but is limited by three factors: facility size, prompt/induced radiation, and treatment cost. Compact cyclotrons/synchrocyclotrons for single-room facilities have reduced space requirements. Linacs can avoid high radiation levels. Yet treatment costs have remained stubbornly high, driven largely by maintenance and staffing costs over the typical 20-30 year facility lifetime. Current technology cannot simultaneously reduce these three factors. By using a long Linac, the Alceli approach sacrifices size limitations, to gain massive improvements in treatment cost and radiation levels. Quadrupling the length of a Linac results in a sixteen-fold reduction in RF power per cavity. Along with other innovations in our design, this leads to a modular warm Linac with distributed solid-state RF amplification, easy and cheap to manufacture and maintain, requiring no water cooling, and a treatment cost of 1/10th of current facilities, making PT much more affordable.