Clinical audits in radiation protection

The purpose of clinical audits is to ensure an ideal use of high-dose ionising radiation in medicine. Their realisation will enable to review the justification of the expositions and to optimise the processes and resources of the providers. A steering committee consisting of the main stakeholders ensures that these audits are implemented in the form of peer reviews.

The essentials in brief

  • In Switzerland, the average dose of ionising radiation used for the purpose of medical diagnosis has increased by 40% over the past 15 years.
  • Several European studies (1, 2, 3) have shown that some of the examinations and treatments that employ ionising radiation are not justified.
  • Clinical audits are not controls carried out by the authority, but reviews conducted by colleagues, also known as peer reviews.
  • The Federal Office of Public Health (FOPH) launched the project of "Clinical audits" in 2011, in close collaboration with professional associations in medicine, medical physics and medical technology. Since 2018, their representatives have formed the steering committee for clinical audits in Switzerland.
  • The Radiological Protection Ordinance (RPO) is the legal basis for clinical audits. Its revised version entered into force on 1.1.2018. The implementation of clinical audits was voluntary until the end of 2019. During this period, the providers were to develop their quality manual (see additional information, only in German, French and Italian).
  • The pilot clinical audits in radiology, radiation oncology and nuclear medicine carried out since 2015 have proven to be useful in terms of protecting patients and organising processes. In addition, minimal overlaps with other audits or quality controls have been observed.


The benefits of using ionising radiation in medicine are undeniable. They allow to visualise the state and position of internal anatomical structures, the physiological processes or, in the case of radiotherapy, to selectively destroy tumour cells. However, the ionising radiation is also associated with certain risks that can affect the body's functioning at various levels (atoms, molecules, DNA, cells, etc.) and cause immediate damage, for example skin rashes. Lesions can also manifest themselves months, or even years, after exposure, for example in the form of cancers.

The risk of tumour induction depends on the effective dose received (expressed in Sievert or Sv), and the patient's gender, age and radio-sensitivity. Young people, for example, are much more sensitive to ionising radiation. The risk of mortality (in the general population) following such exposure is currently assumed to increase, on average, by 5% per Sievert.

In Switzerland, the average dose of ionising radiation received by the population in connection with medical applications has increased by 40% over the past 15 years (1998-2013) (4). This increase is mainly due to CT scans, the use of which has more than doubled since 1998. Examples of radiation doses used in medicine are listed here (only in German, French and Italian).

It is important for the well-being of patients that examinations and treatments using ionising radiation are justified and implemented in the ideal manner. It is therefore essential to carefully weigh the benefits and risks before each use and check whether an alternative method (for example an MRI scan or ultrasound) could produce an equivalent result. If the benefits outweigh the risks, the use of radiation is considered to be justified.


Clinical audits are evaluations conducted by colleagues (also known as peer reviews). They review the practices of a provider and, if necessary, issue recommendations for improving the justification of exposures and optimising the processes and resources. This means that they are therefore neither administrative controls nor inspections conducted by the supervisory authorities.

The concept of clinical audits was introduced in Europe in 1997 by means of the Directive 2013/59/Euratom. Switzerland, which is not a member state of the EU, has drawn on the experience of Finland to define its own organisation of clinical audits. Indeed, Finland can be viewed as a pioneer in this context since all its medical radiology centres have already been audited several times.

In collaboration with the representatives of various professional associations in medicine, medical physics and medical technology, the FOPH has defined the legal bases for clinical audits in the revised Radiological Protection Ordinance (RPO) (5), which entered into force on 1 January, 2018. This revised ordinance now reinforces the principle of justification in medicine (art. 3, 27, 28, 29) and stipulates clinical audits (art. 41-43). (See further details in German, French and Italian)  

Any holder of an authorisation for  medical applications of radiation in computed tomography, nuclear medicine or radiotherapy, or for fluoroscopy-guided interventional diagnostic and therapeutic procedures (high-dose), may be audited every five years and is required to conduct a self-evaluation of its procedures once a year.

Until the end of 2019, the implementation of clinical audits remained optional in order to allow sufficient time for the radiology units to produce their quality manual required by the RPO (see example under "Documents"). Clinical audits are mandatory since 2020.

Organisation of clinical audits in Switzerland

A steering committee was set up and began work in 2018. Its members are representatives of the Swiss Societies of Radiology (SSR), Radiation Oncology (SSRO), Nuclear Medicine (SSMN), Cardiology (SSC), Radiobiology and Medical Physics (SSRPM), the Swiss Association of Medical Radiology Technicians (ASTRM), the Swiss Medical Association (FMH) and the FOPH. Together they define the strategy and implementation of clinical audits based on the experience acquired during the pilot clinical audits.

Committees of experts have been formed for each of the specialties audited. As part of their remit, they are responsible for defining the content of audits and advising the steering committee.

A pool of auditors has been specially trained to carry out clinical audits, for which the audit teams will be interdisciplinary.

The scientific secretariat, integrated within the FOPH, coordinates clinical audits.

Description of a clinical audit

As illustrated in the figure below and the video (also in French or Italian), a team of auditors usually includes a doctor, a medical physicist and a radiographer. Together, they visit the provider to be audited and evaluate their working practices. Each auditor focuses on their area of expertise and compares the practices of their peers against recognised standards.

Clinical audits

At the end of the audit, which usually takes a day, the team of auditors presents its initial recommendations for improving clinical practice and discusses these with the team of the audited unit. Finally, the auditors prepare their report and send it directly to the provider, which is invited to implement the recommendations.


Several information exist in the following languages:

Further information

1. National Survey on Justification of CT-examinations in Sweden (PDF, 748 kB, 09.11.2016)Almén A, Leitz W, Richter S; National Survey on Justification of CT-Examinations in Sweden. Swedish Radiation Safety Authority, 2009:03.

2. Unjustified CT examinations in young patients (PDF, 86 kB, 09.11.2016)Oikarinen H, Meriläinen S, Pääkkö E, Karttunen A, Nieminen M, Tervonen O; Unjustified CT examinations in young patients; Eur Radiol (2009) 19: 1161-1165

3. Audit de la conformité aux bonnes pratiques (PDF, 1 MB, 25.09.2018)Audit de la conformité des prescriptions d'examens d'imagerie médicale: Volet B, Ministère de la santé, Luxembourg, 2017

4. Exposure of the Swiss population by Medical X-rays (PDF, 4 MB, 09.11.2016)Aroua A; Samara E, Bochud F, Verdun F; Exposure of the Swiss population by Medical X-rays: 2008 Review; Institut de radiophysique, June 2011

Last modification 15.09.2020

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