Objectives: In this study, radiotechnologists who work performing PET and PET/CT methodologies were analyzed in order to find the cause for the differences in radiation exposure as they applied to general characteristics, work characteristics, knowledge, and exposure recognition or conduct. Methods: From April 15th, 2010 to May 14th, 2010, we conducted a retrospective analysis on 80 radiotechnologists using data garnered from their individual general characteristics, work characteristics, knowledge, and exposure recognition or conduct. Their average annual radiation exposure dosages were measured using a thermoluminescence dosimeter. A multiple regression analysis was performed as a statistical tool. Results: Regarding the general PET and PET/CT characteristics, when the work experience was short, the exposure dose was higher. The factors of age, marriage, work experience in nuclear medicine, PET, PET/CT, and sex were found to have statistically significant effects. The knowledge, recognition, and conduct factors for the radiotechnologists were affected by unsecure radiation exposure at the moment of carrying, unsecure radiation exposure at the moment of injection, the application of protection at the moment of injection, and the use of auto distributor. It was found that, the use of an auto distributor, efforts in reducing the radiation exposure, unsecure exposure when with a patient, and the application of protective procedures at the moment of injection affected the overall factor of radiotechnologists radiation exposure dose. Conclusions: We believe that if radiotechnologists would reduce their radiation exposure by using auto distributors, make efforts to reduce the chance of exposure, and be conscious of radiation, they would be able to reduce the radiation exposure dose even during unavoidable circumstances.