The goal of this paper was to justify the implementation of finger ring dosimeter measurements with people working with open sources of radiation. We studied the history of PET/CT, its working principles and image rendering. Impact of radiation on human body was also discussed. We also compared our findings with the legal limits of permited radiation, and found it to be very well within those limits. The measurements we took were distinguished between two job descriptions, one of radiologic technologist working in HOT lab, and the other of radiologic technologist working at the console of PET/CT. Their working enviroment and tasks were thoroughly described. We used three kinds of dosimeters to show their radiation exposure: TLD Hp10, TLD Hp0,07, and electronic dosimeter Hp7. Measurements we took during a six month period showed that the radiation exposure of both radiologic technologists was within legal limits. They also showed that a radiological exposure for radiologic technologist in HOT lab was primarily in the region of his hands and fists, which became aparent only with the introduction of finger ring dosimeters Hp0,07. On the other hand, radiological exposure for radiologic technologist working at the console of PET/CT was primarily his whole body because of his interaction with the patient. Therefore, we were able to justify the implementation of finger ring dosimeter Hp0,07 measurements with people working with open sources of radiation.