Current Australian national diagnostic reference levels for multi detector computed tomography

Australian Adult (15+ years) MDCT DRLs

The DRLs below were introduced on 1 July 2018 and supersede the DRLs published in 2012. Information relating to the development of the current DRLs and on the transition from the 2012 DRLs can be found on the 2018 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 region are based on the 16 cm reference phantom. Dose indices for all other scan regions are based on the 32 cm reference phantom.
4. Kidney-ureter-bladder (KUB) is a new category. Provisional DRLs for this category have been set using the data for abdomen-pelvis. This choice is expected to be conservative; facilities should not be overly concerned if their FRL is well below the DRL. Data will be reviewed within 2 years to set specific DRLs that reflect current practice.

Adult (15+ years) MDCT reference level quartiles

The following tables provide additional information on the observed distributions of facility reference levels (FRLs). An FRL is the median dose reported in a survey; the included FRLs are those from surveys submitted to the NDRLS during 2017. These tables are provided for information only – there is no regulatory requirement for facilities to compare their FRLs to them.

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)

Tables 3 and 4 show the quartiles of the FRL distributions but with the surveys categorised by their use of iterative reconstruction. Table 3 shows the quartiles where iterative reconstruction was used and Table 4 shows the quartiles for surveys that did not use iterative reconstruction (which ARPANSA assumed were reconstructed using filtered back projection). Table 5 compares the 75th percentiles from Tables 3 and 4 with national DRLs.

Table 3: Iterative reconstruction FRL distribution percentiles

Table 4: Filtered back projection FRL distribution percentiles

Table 5: Comparison of the diagnostic reference levels (DRLs) and the 75th percentile of the FRL for surveys conducted using filtered back projection (FBP) and iterative reconstruction (IR)

Australian child (5-14 years) MDCT DRLs

For more information see the MDCT statistics page.

Australian baby/infant (0-4 years) MDCT DRLs

For more information see the MDCT statistics page.