Accelerators are used in medicine to treat and produce radioisotopes. For this purpose, numerous types of accelerators are used every day in hospitals, clinics and research centers. Cyclotron is a type of accelerator that can accelerate charged nuclear particles (protons, deuterons, etc.), thereby producing the desired drug. The radiopharmaceutical 201 TL, 67 Ga, 64 Cu and 18 F which are used in diagnosis and treatment can be produced by cyclotrons. Since the cost of launching the accelerators is very high, it is essential to produce a product with maximum radionuclide purity. It is necessary to optimize the energy of the bombarding charegd particles as well as the thickness of the target samples, so that the maximum production efficiency and radionuclide purity of the products can be achieved at the lowest possible cost. Accordingly, with respect to changes in the cross-sections of the primary and secondarey reactions, the optimum conditions should be determined where the main reactions are increased. In addition, due to the reduced energy of the beam during penetration into the target, the thickness of the target should be adjusted in such a way that the protons in the specimen change energy to achieve high radionuclide production efficiency and purity. In fact, it is necessary to optimize the energy of the irradiated protons and the sample thickness. The purpose of this thesis is to determine the optimum energy of proton beam and thickness of the target and the rates of desired and undesirable interactions and the deposit energy left in the targets 203 TL, 68 Zn, 64 Ni, H 2 o( 18 O,%100) for production of radioisotopes 201 TL, 67 Ga, 64 Cu and 18 F. For this purpose we have used MCNP code to simulate and calculate the reaction rates.
