title: The disproportionate risk burden of CT scanning on females and younger adults in Australia: a retrospective cohort study.
abstract: OBJECTIVE
  To explore the interaction of computed tomography (CT) use, dose and radiation risk of Australian Medicare-funded CT scanning and the impact on cancer incidence and mortality.
  
  
  METHODS
  This retrospective cohort study used records of Medicare subsidised CT scans in Australia (2006/07 to 2011/12) and Australian CT dosimetry. The annual number, rate and adjusted likelihood of CT were determined for gender, age and examination type. Incident cancer and cancer-related mortality attributable to CT in Australia were estimated using lifetime attributable risk coefficients, dosimetry and scan numbers.
  
  
  RESULTS
  The number of CT scans increased by 36% from 2006/07 to 2011/12. Only patients aged 0-4 years did not present an increase in CT scanning rates. Females were 11% more likely to be scanned than males. Head, abdomen/pelvis and spine CT scans were the most likely areas scanned. Females were attributed 61% of both incident cancers and cancer-related mortality from 55% of scans performed. Patients aged 15-44 years were attributed 37% of incident cancers and 30% of cancer-related mortality from 26% of CT scans.
  
  
  CONCLUSIONS
  CT in Australia is increasing, including in groups at higher risk from ionising radiation. This presents a complex set of risk/benefit considerations for clinicians and policy makers.
authors.affiliation: Centre for Health Services Research, School of Population Health, University of Western Australia.
authors.forename: David A
authors.initials: DA
authors.lastname: Gibson
authors.forename: Rachael E
authors.initials: RE
authors.lastname: Moorin
authors.forename: James
authors.initials: J
authors.lastname: Semmens
authors.forename: D'Arcy J
authors.initials: DJ
authors.lastname: Holman
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D017281:Cost of Illness; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000209:etiology; D011829:Radiation Dosage; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D017678:Sex Distribution; D012959:Socioeconomic Factors; D014057:Tomography, X-Ray Computed / Q000009:adverse effects* / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: cancer risk; computed tomography; service utilisation