Radiation exposure of patients from computed tomography for COVID-19 diagnosis

Abstract

BackgroundDuring the global Coronavirus Disease 2019 (COVID-19) pandemic, numerous computed tomography (CT) scans were conducted to assess pulmonary abnormalities associated with COVID-19. A number of studies have contributed to our current understanding of radiation doses in the context of chest CT scans for COVID-19 diagnosis, but there remains a discernible gap in the literature regarding organ-level dose assessments. Materials and methodsWe estimated organ and effective dose for the COVID-19-related chest CT patients in the following three steps. First, we collected CTDIvol and DLP from the literature published during and after COVID-19 pandemic period. Second, we developed the probability density functions (PDFs) for the CTDIvol and the starting location of CT scans by age groups from which 1000 sets of patient and technique parameters were created. With CT organ dose calculation software, National Cancer Institute dosimetry system for CT (NCICT), we calculated 1000 sets of plausible organ and effective doses and evaluated summary statistics for the patient population. ResultsThe standard dose protocol administered approximately five times higher CTDIvol (5.4 mGy) to patients undergoing COVID-19-related chest CT scans compared to the low dose protocol (1.1 mGy). The median lung dose (11.8 mGy) for the 1-year-old patients was about 1.5 times greater than that (7.8 mGy) of the adult patients. We found that 75% of whole COVID-19-related CT patients would have received effective doses less than 6.4 mSv and 1.5 mSv when scanned by standard dose and low dose protocols, respectively. ConclusionWe evaluated the distribution of organ and effective dose for the COVID-19-related chest CT patients worldwide by collecting comprehensive data of CTDIvol for the COVID-19-related chest CT scans from the literature and combining them with NCICT organ dose calculator. While past studies have predominantly reported basic CT dose descriptors, our work takes it a step further by reporting organ-level doses and effective doses. Subsequent research endeavors could involve enhancing the precision of radiation dose assessment through the collection of a subset of electronic CT records.