Variable energy cyclotron for proton therapy application

The requirements on characteristics of the proton beams used in medicine are considered. The operational and proposed cyclotrons for proton therapy are briefly described. The technical decisions of creation of the cyclotron with energy variation in the range 70-230 MeV and with current up to 100 nA are estimated. Taking into account the fact that the size and cost of the cyclotron are approximately determined by the maximum proton energy, it is realistically offered to limit the maximum proton energy to 190 MeV and to elaborate a cyclotron project with a warm winding of the magnet for acceleration of H- ions. The energy of the extracted protons for each run is determined by a stripped target radius in the vacuum chamber of the accelerator, and the radiation dose field for the patient is created by the external devices using the developed techniques