Guidance

Diagnostic radiology: national diagnostic reference levels

Details of the national diagnostic reference levels (NDRLs), for clinicians using radiation in medicine.

• From: UK Health Security Agency
• Published: 22 January 2016
• Last updated: 8 July 2025 — See all updates

Documents

National Diagnostic Reference Levels (NDRLs) from 8 July 2025

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National Diagnostic Reference Levels (NDRLs): process to generate, adopt and maintain

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Details

These tables give the national diagnostic reference levels for common X-ray examinations for patients.

NDRLs from previous years are also available:

• 20 November 2024 to 7 July 2025

• 13 October 2022 to 20 November 2024

• 15 June 2022 to 13 October 2022

• 19 August 2019 to 14 June 2022

• 15 November 2018 to 18 August 2019

• 22 January 2016 to 14 November 2018

Published 22 January 2016

Last updated 8 July 2025 + show all updates

1. 8 July 2025

   NDRLs for general radiography, and fluoroscopy and interventional radiography have been updated.

2. 20 November 2024

   Added 'National Diagnostic Reference Levels (NDRLs) from 20 November 2024'.

3. 24 November 2022

   Added process to generate, adopt and maintain NDRLs.

4. 13 October 2022

   Updated with latest mammography and adult CT NDRLs. Year of publication also added to each NDRL value.

5. 14 June 2022

   Updated with latest update, including change to '2b. Paediatric CT examinations'.

6. 19 August 2019

   Added information on new NDRLs for dental radiography, and provided archive links to previous NDRLs.

7. 15 November 2018

   Added new data for NDRLs.

8. 22 January 2016

   First published.