Evaluation of equivalent dose to working staff with oxygen-15-water in positron emission tomographic studies

With its short physical half-life and allowing for higher dosage injections, oxygen-15 labeled water has become increasingly important in many clinical applications. However, the use of oxygen-15 labeled water could potentially result in radiation exposures to working staff exceeding regulatory limits. In this study, thermoluminescent dosimeters (LiF-100H) were attached at various parts of the body to measure the accumulated equivalent doses of a physician and to evaluate the radiation risk to the sensitive organs which could receive as many as 10 intravenous injections of 15O-water for each subject studied. The results showed that during the injections, the hands of a physician received the highest dose, which was about 25.8 times that of the routine chest X-ray dose. If protective shieldings were provided during injection, about 83% of the dose could be effectively reduced. Even without any protective shielding, the estimated maximum dose to the physician was still within the regulatory limit, 50 mSv/year, suggested by ICRP 60. In conclusion, reducing excess radiation exposure to workers, by minimizing the time spent in close contact with patients, increasing the distance from the source and providing suitable protective shielding would be the most effective approach.