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 an d its support system are described. Details of the operation of the cy clotron in a hospital environment are given; the requirements of the h elium liquifier and cryogenic system are described together with a sum mary 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 equivalen t to that of a 4 MV x-ray beam. The depth of maximum dose occurs at ap proximately 9 mm depth and the surface dose is between 40% and 45%. Th e multirod collimator allows for the production of irregularly shaped fields of size up to 26.5 x 30 cm, without excessive exposure to opera ting personnel.