CT scan reference levels published to support lung cancer screening program

The inclusion of low dose chest scans is in response to the introduction of Australia’s new National Lung Cancer Screening Program, which supports early detection in high-risk people such as long-term smokers. 

The Australian Radiation Protection and Nuclear Safety Agency’s (ARPANSA) medical imaging director, Dr Peter Thomas, says ‘by comparing the radiation doses used in imaging procedures to the national reference levels, which ARPANSA maintains, healthcare professionals can identify if doses are unusually high or low’.  

‘By having these national reference points, practitioners can benchmark and adjust their doses if needed.  

‘Our national diagnostic reference levels show that radiation exposure from medical imaging procedures has decreased over time.’ 

‘That’s why we continue to update our reference levels. As the frequency of different scans changes, we will continue to add or remove scans as appropriate.’   

Radiation dose from CT scans has been in the news this year following US research that reported CT-associated cancer could eventually account for 5% of all new cancer diagnoses each year. 

ARPANSA assessed that research as part of its radiation literature survey series, which is updated regularly with expert evaluations on new and topical radiation science. The study highlighted the increased number of CT scans being conducted, which makes efforts to optimise the dose delivered during each CT scan even more important. 

‘CT scans are often used to diagnose more serious health conditions, and if referred appropriately, the health risk of not having a CT scan is likely to be significantly higher than the risk of radiation exposure,’ Dr Thomas said.  

Reference levels for paranasal sinus scans were also introduced to the national diagnostic reference levels on 1 July 2025 due to the relatively high number of procedures undertaken annually. 

As the Australian Government’s primary authority on radiation protection and nuclear safety, our national diagnostic reference levels help the healthcare sector ensure radiation doses from medical imaging are as low as reasonably achievable, avoiding unnecessary exposure.  

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