SHIELDING AND RADIATION SAFETY AROUND A SUPERCONDUCTING CYCLOTRON NEUTRON THERAPY FACILITY

Prior to routine operation of the neutron therapy unit a radiation sur vey was performed in order to confirm the shielding design and to assu re the safety of the personnel involved in the operation of the unit. The shielding requirements were calculated in accordance with NCRP Rep ort No. 51. The contributions of the neutron and gamma dose equivalent s have been measured separately outside the treatment room. The exposu re outside the shield is negligible. In general, the measured values w ere lower than those derived from the shielding calculations. The high est total dose equivalents were registered at locations corresponding to the highest calculated values.