Popis: |
To select the optimum therapeutic neutron beam available from a CS30 medical cyclotron (manufactured by the Cyclotron Corporation, Berkeley, California), central axis depth dose data and output dose rates were compared for the bombardment of beryllium with either the proton or deuteron beams available from the machine. The effect on these parameters of filtering the beams with either pure polyethylene, polyethylene loaded with 5% boron, or polyethylene loaded with 10% lithium was studied. A 4-cm, 10% lithiated filter used with a 26-MeV proton beam was selected for therapeutic use. Buildup curves, beam profiles at several transverse planes for different field sizes, and comparison of beam profiles with 60Co are given. |