Update of multi detector computed tomography adult diagnostic reference levels - March 2021

ARPANSA updated the diagnostic reference levels (DRLs) for adult multi-detector computed tomography (MDCT) procedures in March 2021. Facility dose audits should be compared against these updated MDCT DRLs.

One of the aims when establishing a diagnostic reference level program is to have the DRLs reflect current practice, which requires monitoring and periodic updates to the DRLs. After reviewing data collected in the 2019 calendar year, ARPANSA has updated the DRLs for three scan types: cervical spine, soft-tissue neck, and kidney-ureter-bladder. The revised DRLs are included in the table of current MDCT DRLs published on the ARPANSA website.

DRL review process

The Australian national DRLs for MDCT procedures on adult patients were reviewed and updated in 2018. As part of that review the pre-existing category of neck scans was split into separate soft-tissue neck and cervical spine categories and an additional category for kidney-ureter-bladder (KUB) scans was added to the list of national DRLs. At that time ARPANSA did not have specific KUB data and an interim national DRL was set, based on data for abdomen-pelvis scans. ARPANSA indicated that KUB data would be reviewed within 2 years to update the interim national DRL.

Changes to the scan categories were implemented in ARPANSA’s National Diagnostic Reference Level Service data collection portal in June 2018 and data collection for the revised scan categories commenced from 1 July 2018. There is now sufficient data to set revised national DRLs for KUB scans and to adjust the DRLs for the soft-tissue neck and cervical spine scan regions.

Transitioning to the updated DRLs

The updated DRLs were published on the ARPANSA website in March 2021. The ARPANSA National Diagnostic Reference Level Service MDCT portal was updated on 29 March 2021 to use the revised DRLs for surveys of cervical spine, soft tissue neck, and kidney-ureter-bladder scans. Any surveys for these scan regions completed after the portal update will be compared against the updated DRLs (even if the surveys were started prior to the update). Surveys for other scan regions will not be affected as the DRLs for those scan regions have not changed.

In relation to the requirements of the Diagnostic Imaging Accreditation Scheme (DIAS), there will be a 6 month phase in period, with practices providing these scan types required to submit audit records relating to the new revised DRLs from 1 October 2021.  From 1 October 2021, as part of an application for accreditation (including renewal of accreditation), accreditors will require evidence that policies for undertaking a DRL comparison have been updated and that audits conducted after this date have been compared against all current, established DRLs.