Determination radiation exposure rate at various distances and time for myocardial blood flow study using oxygen-15 water PET/CT imaging

Abstract

Background: Oxygen-15-labelled water is considered a gold standard for myocardial blood flow quantification. The present study aimed to measure radiation exposure rates from patients study with ¹⁵O-water myocardial blood flow (MBF) positron emission tomography/computed tomography (PET/CT) scans, and to assess occupational and public exposure. Methods: Radiation exposure rates from ¹⁵O-water were measured during both rest and stress study. The measurements were obtained at 2.15 min after ¹⁵O-water synthesis 1m away from the generator and 5 cm from the xiphoid level of each patient at time-points of 3.0, 8.30, and 15.0 min. Radiation exposure in the adjacent PET/CT imaging rooms was also surveyed. Results: The mean administered activities were 552.27±30.87MBq and 548.59±35.77MBq during rest and stress, respectively. During the ¹⁵O-water synthesis, the mean radiation exposure rates were 242.90±63.68µSv/h at rest and 254.60±56.92µSv/h during stress. The mean radiation exposure rates at 3.0, 8.30, and 15.0 min were 1305.90±419.64 µSv/h, 121.82±22.89 µSv/h, and 14.62±3.44µSv/h at rest, and 1320.07±451.83µSv/h, 124.49±24.48µSv/h, and 12.50±3.76µSv/h during stress, respectively. Radiation exposure rates in the PET/CT control room and at all locations outside the imaging room were within the background range. Conclusion: During¹⁵O-water PET/CT examinations of MBF patients. The radiation exposure rates from the patients provided the radiation safety for both radiation worker and the public according to the guidelines provided by the International Commission on Radiological Protection and the Office of Atoms for Peace. However the staff should be spend less time near the radiowater generator (this includes the patients after injected radiotracer and imaging), and increasing distance from the radioactive source and patients during diagnosis for deceasing the radiation exposure.