title: Demonstration of the effect of generic anatomical divisions versus clinical protocols on computed tomography dose estimates and risk burden.
abstract: OBJECTIVE
  Choosing to undertake a CT scan relies on balancing risk versus benefit, however risks associated with CT scanning have generally been limited to broad anatomical locations, which do not provided adequate information to evaluate risk against benefit. Our study aimed to determine differences in radiation dose and risk estimates associated with modern CT scanning examinations when computed for clinical protocols compared with those using anatomical area.
  
  
  METHODS
  Technical data were extracted from a tertiary hospital Picture Archiving Communication System for random samples of 20-40 CT examinations per adult clinical CT protocol. Organ and whole body radiation dose were calculated using ImPACT Monte Carlo simulation software and cancer incidence and mortality estimated using BEIR VII age and gender specific lifetime attributable risk weights.
  
  
  RESULTS
  Thirty four unique CT protocols were identified by our study. When grouped according to anatomic area the radiation dose varied substantially, particularly for abdominal protocols. The total estimated number of incident cancers and cancer related deaths using the mean dose of anatomical area were 86 and 69 respectively. Using more specific protocol doses the estimates rose to 214 and 138 incident cancers and cancer related deaths, at least doubling the burden estimated.
  
  
  CONCLUSIONS
  Modern CT scanning produces a greater diversity of effective doses than much of the literature describes; where a lack of focus on actual scanning protocols has produced estimates that do not reflect the range and complexity of modern CT practice. To allow clinicians, patients and policy makers to make informed risk versus benefit decisions the individual and population level risks associated with modern CT practices are essential.
authors.affiliation: Centre for Population Health Research, Curtin University, Perth, Western Australia, Australia; Centre for Health Services Research, School of Population Health, University of Western Australia, Perth Western Australia, Australia.
authors.forename: Rachael E
authors.initials: RE
authors.lastname: Moorin
authors.affiliation: Centre for Health Services Research, School of Population Health, University of Western Australia, Perth Western Australia, Australia.
authors.forename: David A J
authors.initials: DA
authors.lastname: Gibson
authors.affiliation: Department of Medical Imaging Science, Curtin University, Perth, Western Australia, Australia.
authors.forename: Rene K
authors.initials: RK
authors.lastname: Forsyth
authors.affiliation: School of Physics, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Fox
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000715:Anatomy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology / Q000401:mortality; D011829:Radiation Dosage; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed / Q000009:adverse effects* / Q000379:methods*; D055815:Young Adult