Abstract |
Diagnostic Reference Levels (DRLs) are a form of investigation levels used as a
tool to aid optimization of protection in the medical exposure of patients to ionizing
radiation. DRLs are set in local, national or regional level and are an indication of the
acceptable average dose values a patient receives, for a particular examination, in a
health facility in that area. DRL quantity is defined as a commonly used and easily
measured or calculated quantity, by which the amount of ionizing radiation used to
perform an examination is estimated.
The main purpose of this study is the determination of typical values (median
values) of the DRL quantities of SPECT-CT examinations performed in the University
General Hospital of Heraklion. These examinations were myocardial perfusion and
parathyroid imaging with the use of Tc-99m Tetrofosmin and Sestamibi as
radiopharmaceutical and bone imaging with the use of Tc-99m HDP as
radiopharmaceutical. As until today, there are no national DRL values set for SPECTCT examinations in Greece, the results of this study could be used as a first step in the
direction of their determination. In addition, the comparison of the typical values
found for the department, with DRL values published in the international literature for
the respective examinations, can be used as an indication in quality control of the
department and help in the further optimization of the practices used.
The experimental part of this study took place in the Department of Nuclear
Medicine of the University General Hospital of Heraklion, during the winter semester
of the academic year 2021-2022. There, data of activity of radiopharmaceuticals
administered to patients undergoing the most common SPECT-CT examinations were
collected, as well as corresponding computed tomography dose data (DLP and
CTDIvol). Afterwards, the collected data were statistically analyzed in order to obtain
the results of this study. In addition to the typical dose values of SPECT-CT
examinations, with the data collected, it was possible to determine the typical values
of DRL quantities for myocardial perfusion and bone imaging SPECT examinations. The
typical values found for each one of the five exams mentioned above, are compared
with DRL values found in the literature. Finally, the median total Effective Dose of
patients undergoing the SPECT-CT examinations is calculated, as a means of better
understanding their exposure to ionizing radiation.
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