A superconducting cyclotron for neutron radiation therapy.

The physical and clinical specifications of a neutron therapy facility utilizing a superconducting cyclotron are presented. The cyclotron and its support system are described. Details of the operation of the cyclotron in a hospital environment are given; the requirements of the helium liquifier and cryogenic system are described together with a summary of its mode of operation. The simplicity of the cyclotron control system is discussed. The physical characteristics of the neutron beam are described. The central axis percent depth dose curve is equivalent to that of a 4 MV x-ray beam. The depth of maximum dose occurs at approximately 9 mm depth and the surface dose is between 40% and 45%. The multirod collimator allows for the production of irregularly shaped fields of size up to 26.5 x 30 cm, without excessive exposure to operating personnel.