title: Reconstruction of paediatric organ doses from axial CT scans performed in the 1990s - range of doses as input to uncertainty estimates.
abstract: OBJECTIVE
  To assess the range of doses in paediatric CT scans conducted in the 1990s in Norway as input to an international epidemiology study: the EPI-CT study, http://epi-ct.iarc.fr/ .
  
  
  METHODS
  National Cancer Institute dosimetry system for Computed Tomography (NCICT) program based on pre-calculated organ dose conversion coefficients was used to convert CT Dose Index to organ doses in paediatric CT in the 1990s. Protocols reported from local hospitals in a previous Norwegian CT survey were used as input, presuming these were used without optimization for paediatric patients.
  
  
  RESULTS
  Large variations in doses between different scanner models and local scan parameter settings are demonstrated. Small children will receive a factor of 2-3 times higher doses compared with adults if the protocols are not optimized for them. For common CT examinations, the doses to the active bone marrow, breast tissue and brain may have exceeded 30 mGy, 60 mGy and 100 mGy respectively, for the youngest children in the 1990s.
  
  
  CONCLUSIONS
  The doses children received from non-optimised CT examinations during the 1990s are of such magnitude that they may provide statistically significant effects in the EPI-CT study, but probably do not reflect current practice.
  
  
  CONCLUSIONS
  • Some organ doses from paediatric CT in the 1990s may have exceeded 100 mGy. • Small children may have received doses 2-3 times higher compared with adults. • Different scanner models varied by a factor of 2-3 in dose to patients. • Different local scan parameter settings gave dose variations of a factor 2-3. • Modern CTs and age-adjusted protocols will give much lower paediatric doses.
authors.affiliation: Norwegian Radiation Protection Authority (NRPA), P. O. Box 55, NO-1332, Østerås, Norway. hilde@olerud.net.|HSN University College of Southeast Norway, P.O. Box 235, NO- 3603, Kongsberg, Norway. hilde@olerud.net.
authors.forename: Hilde M
authors.initials: HM
authors.lastname: Olerud
authors.affiliation: Gjøvik University College, Teknologivn. 22, NO- 2815, Gjøvik, Norway.
authors.forename: Benthe
authors.initials: B
authors.lastname: Toft
authors.affiliation: Norwegian Radiation Protection Authority (NRPA), P. O. Box 55, NO-1332, Østerås, Norway.
authors.forename: Silje
authors.initials: S
authors.lastname: Flatabø
authors.affiliation: Luxembourg Institute of Science and Technology (LIST), 29 Avenue John F. Kennedy, L-1855, Luxembourg, Luxembourg.
authors.forename: Andreas
authors.initials: A
authors.lastname: Jahnen
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, 9609 Medical Center Dr., Rockville, MD, 20850, USA.
authors.forename: Choonsik
authors.initials: C
authors.lastname: Lee
authors.affiliation: International Agency for Research on Cancer, 150, Cours Albert Thomas, Lyon, 69008, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Thierry-Chef
mesh_terms: D000293:Adolescent; D000328:Adult; D001853:Bone Marrow / Q000000981:diagnostic imaging; D001921:Brain / Q000000981:diagnostic imaging; D001940:Breast / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008962:Models, Theoretical; D009664:Norway; D010372:Pediatrics / Q000706:statistics & numerical data*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data; D035501:Uncertainty
keywords: Dose–response relationship, radiation; Paediatrics; Radiation dosage; Radiologic health; Tomography scanners, X-ray computed