Current Australian national diagnostic reference levels for multi detector computed tomography

Australian Adult (15+ years) MDCT DRLs

The current diagnostic reference levels (DRLs) for multi detector computed tomography (MDCT) scans on adult patients are shown below (Table 1) and were last updated in July 2025. Information relating to the development of the DRLs and on transitional arrangements for the most recent update can be found on the 2025 MDCT update and the MDCT statistics pages.

Table 1: Multi detector computed tomography diagnostic reference levels for adults

Notes:

1. Diagrams of the scan regions and additional protocol information are available from the before you enter data page.
2. The scans included in a dose comparison do not necessarily have to be for the listed phase/indication; however, the exposure parameters of the included scans must match what would be used for the listed phase/indication.
3. Dose indices for the Head and Paranasal Sinuses regions are based on the 16 cm reference phantom. Dose indices for all other scan regions are based on the 32 cm reference phantom.
4. New scan categories will be reviewed once sufficient Australian data is collected.

Adult (15+ years) MDCT reference level quartiles

The table below offers detailed information regarding the observed distributions of facility reference levels (FRLs). An FRL represents the median dose reported from a survey of patient doses for a particular scan protocol, on a specific scanner, at a given facility. This quartiles data is provided solely for informational purposes; there is no regulatory mandate for facilities to compare their FRLs against this data.

Table 2 shows the rounded 25th and 50th percentiles of the FRL distributions and compares them to the national DRLs. Facilities can use this additional information to gain a better understanding of how their FRLs compare to those of other facilities. If your FRL is near the 50th percentile you are approximately consistent with most other sites. If your FRL is below the 25th percentile you are amongst the lowest dose sites. It is important to ensure that the image quality in your scans is sufficient for the clinical task.

Table 2: FRL distribution percentiles and diagnostic reference levels (DRLs)

^{Footnote: The percentiles are derived from data submitted to the ARPANSA National Diagnostic Reference Level Service (NDRLS) in 2023. Analysis of the most recent data can be found on the MDCT Statistics page.}