Reduction in radiation exposure to patients and personnel in PET/CT examinations

Abstract

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Learning Objectives: PET/CT produces fused images, incorporating the benefits of PET and CT, and now guides patient management as an indispensable imaging modality. It requires radiation safety standards of both techniques of PET and CT for patients as well as personnel. We demonstrate how radiation exposure could be well managed.

Abstract Body: Radiation protection is of concern for personnel who care patients administered with positron pharmaceuticals and then a radiation source themselves. We have proposed and implemented radiation safety measures in our PET/CT department based upon updated standards. Automated injector of FDG (Sumitomo Heavy Industries) reduced radiation exposure of personnel. For a PET/CT scanner (biograph, Siemens) with sensitive LSO detectors, FDG dose to a patient was optimized by considering image quality and determined at 3 MBq/kg, which lowered radiation exposure of patients and workers. The CT component had the CareDose system reducing patient radiation dose. Estimated effective dose for a patient was 10 mSv per study (3 and 7 mSv for PET and CT). In the aim of reducing radiation exposure to personnel, we undertook additional countermeasures; in-depth radiation monitoring which spotted high radiation areas, supplementary lead shields around injection tubes and liquid waste bottles, and guidance to patients prior to injection. As a result, the radiation dose of a nurse in FDG administration per one patient decreased from 0.43 to 0.04 µSv (June 2006 versus June 2007, mean of 50 patients, respectively). In conclusion, radiation exposure of patients and workers was well reduced through radiation monitoring and countermeasures. This optimization process is important because nowadays increasing number of patients undergo PET/CT worldwide.