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The National Diagnostic Reference Level Service

The Australian National Diagnostic Reference Level Service (NDRLS) provides individual facilities with a tool for comparing their representative medical imaging patient dose metrics with the National Diagnostic Reference Levels (DRLs). The data from individual facilities is collated and used to establish and update National DRLs for common diagnostic imaging procedures.

National DRLs are intended as indicative dose metrics for current imaging practice in Australia, allowing individual facilities to compare their facility reference dose metrics  against a national benchmark.

Facility Reference Levels (FRLs) are calculated from a representative sample of patients and national DRLs are calculated from the national distribution of FRLs. However,  it may be useful to compare the dose metric for an individual patient against the local FRL to assess whether the exposure was consistent with usual practice at the facility.

The Service is available for Multi Detector Computed Tomography, for Nuclear Medicine, and for Image-Guided Interventional Procedures (diagnostic and therapeutic).  Future developments will encompass other medical radiation imaging modalities.

A comprehensive, confidential dosimetry report will be made available to the registered facility for each submitted data set. This report will detail the facility’s doses compared with Australian National DRLs. These reports can be used as evidence of compliance with the Code of Practice for Radiation Protection in the Medical Applications of Ionizing Radiation, RPS 14, Section 3.1.8(a).

NDRL principal stakeholders

Further information on International Best Practice for Radiation Protection of Patients can be found on the International Atomic Energy Agency Radiation Protection of Patients website, which can be accessed via the following link:

IAEA Radiation Protection of Patients (RPOP):


The NDRLS undertakes three modality surveys - MDCT (multi detector computer tomography), nuclear medicine and PET, and IMGP (image guided interventional procedures)

Tables presenting the current national diagnostic reference levels for multi detector CT

National Diagnostic Reference Level Service monthly service user statistics

A listing of frequently asked questions relating to the national diagnostic reference level service and diagnostic reference levels