Radiological safety aspects of self-shielded medical cyclotron

Radiological safety around self-shielded medical cyclotrons, installed at two different nuclear medicine centers in the country has been assessed at the time of commissioning. An attempt has been made to measure gamma and neutron radiation levels inside the cyclotron vault/room. The mixed neutron field (thermal and fast neutron) has been measured using BF3 proportional counter and CR-39 foils. The gamma radiation levels have been monitored with the help of four dosimetric instruments: high pressurized ionization chamber, NaI(Tl) scintillation detector, diode based dosimeters and LiF:Mg,Cu,P Thermoluminescent (Tl) dosimeters. The gamma and neutron radiation levels inside the cyclotron vault/room were found in the range of 10.8 - 14.5 μSv/h and 0 - 16.8 μSv/h respectively. (author)