Introduction: In positron emission tomography / computed tomography (PET/CT)
examinations ionising radiation of higher energies is used compared to classical nuclear
medicine examinations. Consequentially, health care workers, who work with PET/CT, could
receive higher radiation doses than health care workers who work in classical nuclear
medicine.
Purpose: The purpose of the master's thesis was to explore if introduction of PET/CT
examination procedures to the Department for Nuclear Medicine (KNM) at the University
Medical Centre in Ljubljana has affected in elevated personal radiation doses of health care
workers who are executing PET/CT examinations.
Materials and methods: The research included 27 workers from the diagnostic centre of
KNM: 7 physicians, 10 radiologic technologists, 5 radiopharmacists, and 5 qualified nurses.
In the years 2008 and 2009 these workers were performing classical nuclear medicine
examinations, whereas in the years from 2010 to 2012 they also worked with PET/CT
examinations. Research methods – we analysed the radiation dose measurements for the
period 2008–2012, which had been measured with personal thermoluminiscent dosimeters
and read by the Institute Occupational Safety. Additionally, we measured daily personal
radiation doses for physicians, radiologic technologists, and radiopharmacists who cooperated
in PET/CT examinations. We used calibrated electronic dosimeters.
Results: As a consequence of cooperation in PET/CT examination procedures, the annual
radiation dose has significantly increased for physicians (mean dose 0.18 mSv in year 2009
and 0.39 mSv in 2010; p = 0.005) and for the radiologic technologists (mean dose 0.82 mSv
in 2009 and in 1.04 mSv in 2010; p = 0.034). The radiation doses for radiopharmacists and
qualified nurses have not significantly changed.
Mean daily radiation dose, received by a physician performing PET/CT examination
procedures, was 3.1±2.4 μSv. Two radiologic technologists who cooperated in PET/CT
examinations as a team, received combined daily dose of 5.1±3.4 μSv and the
radiopharmacist received <1 μSv. A mean radiation dose, received as a consequence of
collaboration in a single PET/CT examination, was 0.34 μSv for a physician and 0.28 μSv for
radiologic technologist.
Conclusion: Following the introduction of PET/CT examinations, the annual radiation doses
have increased for health care workers at KNM. Statistically significant increase was
measured for physicians and radiologic technologists. For radiopharmacists and qualified
nurses the increase was not statistically significant. Mean radiation doses, received by
workers in one single PET/CT examination, were lower than measurements reported in the
literature. This observation might be a consequence of good organization of work and
consistent abiding with the ionising radiation protection rules.
Keywords: PET/CT examination, personal radiation dose, health care workers, radiologic
technologist, nuclear medicine
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