Organ dose in paediatric CTs – trends in time: results from the German cohort study

Auteurs

R. Pokora, L. Krille, E. L. Gianicolo, S. Dreger, C. Lee, A. Jahnen, H. Zeeb, and M. Blettner

Référence

in Old and New Risks: Challenges for Environmental Epidemiology. 28th annual meeting of the International Society for Environmental Epidemiology (ISEE), At Rome, Italy, 1–4 September 2016, P1-319

Description

Computed tomography (CT) imaging is an important and rapidly advancing diagnostic tool in modern medicine. New epidemiological studies raised concerns about possible cancer risks after exposure to ionizing radiation from CT examinations in childhood. However, scanner-based dose reduction techniques have also evolved and the German Commission on Radiological Protection made recommendations for paediatric CT-use. Our primary objective is to assess the radiation exposure in individuals through CT scanning during childhood and to analyse trends in CT radiation doses over time.

Dosimetry data was extracted from the Picture Archiving and Communication System (PACS) of 18 participating hospitals for all children who underwent a CT from 1997 to 2013. We determined the exposed body region by performing a lexical analysis of PACS descriptive data. Organ doses were then calculated using National Cancer Institute dosimetry system for CT (NCICT) software to generate a CT-exposure-matrix.

The cohort included information on 26,212 paediatric CT examinations. Overall, 63% of all examinations focused the head followed by chest scans (19%). In the youngest age group (< 4 months), the proportion of head-CT was lowest (52%) against 69% in the age group 0.4-2.5 years. The highest average doses (up to 41 mGy) were delivered to the brain during head CT examinations. Average doses to other organs remained below 14 mGy for all examinations and all ages. Standard deviations associated with our mean dose values reflect large variability in doses in our dataset. From 1999 onward, organ doses of head CTs decreased with calendar year. Mean organ doses by head CTs increased between 1 and 12.5 years of age. Mean doses were higher for newborn than for 1-year-old children.

We were able to show that organ doses in paediatric CT examinations decrease with calendar year and decreasing age. Further analyses will estimate individual organ doses for paediatric examinations that are not included in the PACS.

Lien

http://ehp.niehs.nih.gov/isee/2016-p1-319-3576/