[Positron emission tomography and radiation exposure]

With the ever increasing number of PET-systems in operation the associated problems of radiation protection gain increasing significance. Compared to "conventional" nuclear medicine there is a need for better shielding since the production of positron emitters also yields neutrons and secondary gamma radiation. Due to the short half-lives involved the radiochemistry has to handle high initial activities. Moreover the 511 keV energy of the positron-emitters results in the vicinity of the patient in a higher exposure rate than other nuclear medicine isotopes. For these reasons the typical effective dose to cyclotron personnel is about 2 mSv per year. The whole-body dose to the radiochemists is reported to be 0-20 microSv per charge, and to the medical personnel 10-50 microSv per application. The radiation exposures of the patients are comparable to those common in "conventional" nuclear medicine.