[en] The consideration of the iodine-123 production on the LU-100 linear accelerator were studied. The excitation functions of the (p, 3n) and (p, 5n) reactions at the irradiaton of sodium iodine with 100 MeV protons have been measured. The yield and radionuclide purity of iodine-123 produced via xenon-123 separated from the target in on-line regime have been determined. The experimental results indicated that iodine-123 yield was by more than 30% over the 100-48 MeV proton energy range than those obtained for 66-46 MeV range. The contamination of iodine-125 was as high as 0.14% (EOB+6 h)