| Aim: The aim of this study was to find an optimum material for protective garment for protection against 99Tcm radionuclide. Materials and methods: Monte Carlo simulation code was applied to investigate radiation attenuation of 13 shielding materials including: Ba, gray Sn, white Sn, Sb, Bi, Bi2O3, BaSO4, Sn/W, Sb/W, Pb, and W with thicknesses of 0.5 and 1 mm to determine an optimum protective garment material in nuclear medicine against 99Tcm. Furthermore, the dose enhancement on the staff body was investigated for shielding materials such as tungsten and lead. Results: The findings of the simulations show that the maximum and minimum attenuations obtained with thicknesses of 1 mm W and 1 mm BaSO4 were 96.46% and 14.2%, respectively. The results also show that tungsten does not cause dose enhancement on staff's body but this is not true for lead. Tungsten provides the highest radiation attenuation without dose enhancement on the body of staff. Conclusion: Among the materials evaluated, tungsten is the optimum material and can be applied for design of protective garment for nuclear medicine staff against 99Tcm. |