[en] In the last decade positron emission tomography (PET) has been widely used for imaging organ function. In a cyclotron, accelerated proton interaction with the target or the component material produces neutron and gamma radiation. The use of cyclotrons for medical purposes is necessary to monitor the exposure to neutron and gamma radiation. In this study, measurement of gamma dose, neutron dose and its spectrum were carried out on the outer wall of the 18 MeV cyclotron PET radiation shielding. Gamma dose measurements were performed using four environmental OSL dosimeters. The dosimeters are wrapped in aluminum foil to prevent the Al₂O₃:C element from being exposed to light and mounted on the outside of the entry bunker wall, power supply wall, and general store wall of cyclotron shielding 18 MeV IBA MRCCC, Siloam. Measurement of neutron is done using a BSS device mounted on the measurement position of the outer wall of the bunker entry and the outside wall of the general store. The highest dose of gamma obtained in the outer position of the shielding was (367 ± 10.6 %) μSv/3 months. The result confirmed that the thickness of the 220 cm concrete shielding construction is capable of absorbing the generated gamma radiation. The result of neutron calculations show that the largest ambient dose rate comes from fast neutron in the outside position of the wall of the bunker entry was (0.475 ± 12 %) μSv/h, while in the outside position of the general store wall was (0.331 ± 12 %) μSv/h. The epithermal and thermal neutron of ambient dose rate, however were very small. (author)