Derivation of Australian diagnostic reference levels for paediatric multi detector computed tomography

Australian National Diagnostic Reference Levels for paediatric multi detector computed tomography were established for three protocols, Head, Chest and AbdoPelvis, across two age groups, Baby/Infant 0-4 years and Child 5-14 years by the Australian Radiation Protection and Nuclear Safety Agency in 2012. The establishment of Australian paediatric DRLs is an important step towards lowering patient CT doses on a national scale. While Adult DRLs were calculated with data collected from the web based Australian National Diagnostic Reference Level Service, no paediatric data was submitted in the first year of service operation. Data from an independent Royal Australian and New Zealand College of Radiologists Quality Use of Diagnostic Imaging paediatric optimisation survey was used. The paediatric DRLs were defined for CTDIvol (mGy) and DLP (mGy·cm) values that referenced the 16 cm PMMA phantom for the Head protocol and the 32 cm PMMA phantom for body protocols for both paediatric age groups. The Australian paediatric DRLs for multi detector computed tomography are for the Head, Chest and AbdoPelvis protocols respectively, 470, 60 and 170 mGy·cm for the Baby/Infant age group, and 600, 110 and 390 mGy·cm for the Child age group. A comparison with published international paediatric DRLs for computed tomography reveal the Australian paediatric DRLs to be lower on average. However, the comparison is complicated by misalignment of defined age ranges. It is the intention of ARPANSA to review the paediatric DRLs in conjunction with a review of the adult DRLs, which should occur within 5 years of their publication.