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Update of national diagnostic reference levels for adult CT in Switzerland and assessment of radiation dose reduction since 2010

  • Computed Tomography
  • Published:
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Abstract

Objectives

To update the national diagnostic reference levels (DRLs) for adult CT in Switzerland using dose management software and to compare them to the previous Swiss DRLs from 2010.

Methods

CT dose data from 14 radiological institutes with a total of 50 CT scanners were collected with locally installed dose management software between 2014 and 2017. Data were assigned to 15 defined master protocols. Data cleaning steps were developed and adjusted individually for each participating institute and protocol. The DRLs for each master protocol were calculated as the 75th percentile of the distribution of the median volume computed tomography dose index (CTDIvol) and dose-length product (DLP) values per CT scanner.

Results

In total, 220,269 CT exams were available after data cleaning. Updated DRLs showed a clear trend towards lower doses compared with previous DRLs. The average relative change in the DRLs for CTDIvol was − 30% (0 to − 47%) and − 22% for DLP (+ 20 to − 40%). The largest relative decrease in the DRL for DLP was observed for the cervical spine protocol (− 40%), the two chest protocols (chest, − 37%; and exclusion of pulmonary embolism, − 33%), and the two neck protocols (neck, − 32%; and carotid angiography, − 28%). The DRLs for other protocols, for example the head and the abdomen-pelvis protocol, showed smaller relative changes (− 11% and − 17%).

Conclusions

The updated national DRLs are substantially lower than the previous values from 2010, demonstrating technological progress and the efforts of the radiological community to lower CT radiation exposure.

Key Points

• Dose management software allows the establishment of DRLs based on big data.

• Updated Swiss DRLs for adult CT are substantially lower compared with those from 2010.

• Swiss DRLs are low compared with other national DRLs.

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Abbreviations

CT:

Computed tomography

CTDIvol :

Volume computed tomography dose index

DLP:

Dose-length product

DRL:

Diagnostic reference level

FOPH:

Federal Office of Public Health (Switzerland)

HCC:

Hepatocellular carcinoma

ICRP:

International Commission on Radiological Protection

IQR:

Interquartile range

PE:

Pulmonary embolism

SSDE:

Size-specific dose estimate

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Acknowledgements

The authors gratefully acknowledge the support from the participating radiological institutes in data collection, protocol matching, and data cleaning. In particular, the authors thank the following persons (sincere apologies to anyone unintentionally forgotten in this list): Prof. Dr. Hatem Alkadhi, Karen Bader, Julie Bize, Dr. Xavier Boulanger, Dr. Thomas Egloff, Christel Elandoy, René Franke, Dr. Stefano Gianolini, Judith Grothues, Dr. Christina Heilmaier, Prof. Dr. Rowland Illing, Katia Katsari, Martin Kolodziej, Dr. Carsten Krautmacher, Dr. Thiago Lima, Britta Madry-Gevecke, Barbara Markert, Dr. Jörg Mauch, Dr. Roman Menz, Prof. Dr. Xavier Montet, José-Carlos Mourin, Dr. Claude Nauer, Dr. Hans-Werner Ott, Florian Pröhl, Dr. Natalia Saltybaeva, Dr. Marta Sans Merce, Dr. Sabine Schmidt Kobbe, Roland Simmler, Géraldine Stadelmann, Prof. Dr. Francis Verdun, Prof. Dr. Dominik Weishaupt, Dr. Matthias Werner, and everybody else involved without direct contact with the authors.

Funding

This study has received funding by the Swiss Federal Office of Public Health (FOPH), contract number 16.001593.

Author information

Authors and Affiliations

  1. Department of Radiology, University Hospital Basel, University of Basel, Petersgraben 4, 4031, Basel, Switzerland

    Christoph Aberle

  2. Department of Diagnostic and Interventional Radiology, Lausanne University Hospital, Lausanne, Switzerland

    Nick Ryckx

  3. Radiation Protection Division, Federal Office of Public Health, Bern, Switzerland

    Reto Treier

  4. Institute of Radiology, Cantonal Hospital of Aarau, Aarau, Switzerland

    Sebastian Schindera

Authors
  1. Christoph Aberle
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  2. Nick Ryckx
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  3. Reto Treier
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  4. Sebastian Schindera
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Corresponding author

Correspondence to Christoph Aberle.

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Guarantor

The scientific guarantor of this publication is Sebastian Schindera, MD.

Conflict of interest

The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

Written informed consent was not required for this study because it was a retrospective study using anonymous dose data. Patient treatment was not at all affected and identification of patients is not possible.

Ethical approval

Institutional Review Board approval was obtained.

Study subjects or cohorts overlap

Some study subjects or cohorts have been previously reported at ECR 2019: scientific session SS1413, presentation B-1196.

Methodology

• retrospective

• multicentre study

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Aberle, C., Ryckx, N., Treier, R. et al. Update of national diagnostic reference levels for adult CT in Switzerland and assessment of radiation dose reduction since 2010. Eur Radiol 30, 1690–1700 (2020). https://doi.org/10.1007/s00330-019-06485-1

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  • DOI: https://doi.org/10.1007/s00330-019-06485-1

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