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Publications and reports : Health

CT scan procedures in children in France over the period 2012-2018 and associated radiological exposure

Publication date: 20/07/2022


In accordance with its missions in the “Code de la santé publique” (French Public Health Code), the French Institute for radiation protection and nuclear safety (IRSN) periodically analyses the exposure of the French population to ionising radiation due to diagnostic medical imaging procedures. To complete the "ExPRI 2017" study on exposure to ionising radiation of the general population due to diagnostic procedures in France in 2017, a specific study was conducted about CT (computed tomography) scan procedures in children under 16 years of age in France over the period 2012-2018 and the associated radiological exposure.

This study was based on CT scan procedures in children extracted from a representative sample panel of health insurance beneficiaries. The year-by-year analysis (i.e., without individual follow-up of the children from one year to the next) made it possible to evaluate, among other things, the evolution over the period studied of:
  • the frequency of CT scan procedures (number of procedures per 1,000 children) per year;​
  • the proportion of children who had at least one CT scan procedure per year.

Over the period 2012-2018, the annual frequency of CT scan procedures was relatively constant (across all ages and sexes) and fluctuated around 13.7 procedures per 1,000 children.
On average over the same period, the annual frequency of CT scan procedures varies greatly according to the age of the child: about 15 ‰ for children under 1 year old, less than 10 ‰ between 1 and 9 years old, then increasing to more than 35 ‰ at 15 years old.

Over the period studied, 1.1% of children under 16 years of age had at least one CT scan procedure per year. Among this population, the average number of CT scan procedures per year per child was 1.23; 11% to 16% of these children had 2 or more CT scan procedures depending on the year considered.
Since CT and MRI (magnetic resonance imaging) have a large number of common indications and the recommendations of professionals are moving towards a transfer of some procedures to MRI, a study of the evolution of MRI procedures was also carried out. This study shows that, unlike in CT, the annual frequency of MRI procedures increased significantly (+59%) over the period studied.

According to the paediatric data analysed in the Diagnostic Reference Level (DRL) system managed by IRSN, the doses received by children for a CT scan (for the brain, abdomen-pelvis and thorax) show a decreasing trend between the periods 2011-12 and 2016-18. This decrease should be interpreted with caution due to the small amount of data collected during these periods. A new order on DRLs, published in May 2019, has strengthened the provisions for sending dose assessments to IRSN in paediatrics and has made it possible to obtain more data over the period 2019-2021. Analysis of these data in the next DRL review, to be published, will provide more precise information on changes in ionising radiation doses received by children.

Exposure of the population to ionising radiation from diagnostic medical imaging procedures in France in 2017

Publication date: 05/10/20

This report is part of the ExPRI (Exposure of the population to ionising radiation) system launched in 2003, and aims to establish data on the exposure of the French population to ionising radiation from medical imaging for diagnosis purposes (conventional, dental and interventional radiology, computed tomography and nuclear medicine) for the year 2017 and to analyse variation in such data. The study was performed based on diagnostic imaging procedures taken from the échantillon généraliste des bénéficiaires, a sample on a 1/97th scale of the healthcare consumption of the population covered by the main French health insurance schemes.

The exposure of the French population had not changed significantly in 2017 compared with 2012. Variation detected in terms of the mean frequency of imaging procedures and the average per caput annual effective dose is generally minor, excluding dental radiology. In particular, the almost 90% increase recorded between 2002 and 2012 for the average per caput annual effective dose was no longer evident between 2012 and 2017, and levels stabilised at 1.53 mSv per caput (vs. 1.56 mSv in 2012). Nuclear medicine, which ranks number 3 in terms of the collective effective dose, recorded the greatest increase over this 5-year period, in terms of both frequency and contribution to the collective effective dose. Computed tomography remains the most significant contribution to the exposure faced by the population (74.2%) by far. However, the increase in collective effective dose attributable to computed tomography (+2.4%) remains well below the frequency of these imaging procedures, which increased substantially over the period in question (+17%). The frequency of dental radiology procedures is falling steeply (-16.8%). However, this variation was driven by major changes to the CCAM (social security) codes used to record dental radiological imaging over the 2012-2017 period and cannot therefore be considered as sufficiently reliable.

In 2017,  45.4% of the population was subjected to diagnostic medical imaging procedures one or several times, representing a slight increase since 2012 (43.8%). This percentage falls to 32.7% if dental examinations are excluded. Only a small percentage of patients − but representing several hundreds of thousands of patients throughout France − combined multiple computed tomography examinations, leading to high effective doses, potentially exceeding 100 mSv. Although these patients are very certainly treated for serious pathologies, potential long-term radio-induced effects must be considered..
Download the report "Exposure of the population to ionising radiation from diagnostic medical imaging procedures in France in 2017".


​Analysis of data for updating diagnostic reference levels in radiology and nuclear medecine : 2016-2018 report

Publication date: 22/09/20

IRSN is publishing its sixth triennial report on the analysis of dosimetric data transmitted by medical imaging professionals in application of the regulations relating to diagnostic reference levels (DRL).
This report covers the data collected by IRSN over the period 2016-2018. It confirms the merits of several regulatory changes introduced by the order of May 23, 2019 in line with the strengthening of requirements at European level and the recommendations issued by IRSN in its previous reports, in particular to improve data collection and use of DRL in pediatrics.
Download the 2016-2018 report "Analysis of data for updating diagnostic reference levels in radiology and nuclear medecine".


The CT scanner installed base in France and recommendations for radiation protection in medical imaging

Publication date: 04/11/19

In answer to a joint request from the Directorate General for Health (DGS, Ministry of Health) and the Directorate for Social Security (DSS) regarding the French computed tomography (CT) scanner installed base and recommendations on good practices taking into account the needs of radiation protection in medical imaging, IRSN used two databases for which it is responsible by regulations: SIGIS, the information and radioactive sources management system (, and the application for the diagnostic reference levels management. IRSN also held hearings with associations of professionals on topics in connection with the request.
This study highlights the need for change by focusing on IRSN’s field of competence: radiation protection.
Download the study on the CT scanner French installed base.


Exposure of children to ionising radiation due to diagnostic medical imaging procedures performed in France in 2015

Publication date: 08/07/2019 

The purpose of this report is to establish data for the year 2015 on the exposure of French children aged under 16 years to diagnostic medical imaging procedures involving ionising radiation (conventional and dental radiology, diagnostic interventional radiology, computed tomography and nuclear medicine). The study was conducted using the échantillon généraliste des bénéficiaires, a sample on a 1/97th scale of the healthcare consumption of the population covered by the main French health insurance schemes.

Around 604 diagnostic procedures ​​per 1.000 children were performed in 2015, a near stable figure (+1.5%) compared to the year 2010. The proportion of children who had at least one diagnostic procedure was 31%, up by 2 points from 2010. The annual mean effective dose is 0.135 mSv per child, exposed or not, down 25% from 2010, while the mean effective dose per exposed child is 0.43 mSv, down 34% from 2010. Exposure is extremely varied among exposed children, since half of them received a cumulative annual effective dose of 0.02 mSv or less. Relative to the number of children exposed in their age group, children aged under 1 year are the most highly exposed category, with a median annual effective dose of 0.55 mSv.

Children's exposure to ionising radiation originating from diagnostic medical imaging procedures decreased markedly in France between 2010 and 2015, even though the mean frequency of these procedures remained nearly stable over the same time period. This reduction in exposure is therefore due solely to an overall decrease in the mean dose per medical imaging procedure, which is related to improvements in technologies and practices.

Download the report IRSN PSE-SANTE/SER/2018-00004 « Exposure of children to ionising radiation due to diagnostic medical imaging procedures performed in France in 2015 » (PDF, 1,3 Mo)

Explanatory note regarding the new dose coefficients for radon recommended in ICRP Publication 137

Publication date: 18/12/2018

In January 2018, the International Commission on Radiological Protection (ICRP) issued its Publication 137 (Occupational Intakes of Radionuclides: Part 3). That document is part of a series of publications that aim to provide basic data and parameters, for the main chemical elements and their radioactive isotopes, to describe the distribution of these elements in the human body in the event of intake.

IRSN’s explanatory note presents the new dose coefficients adopted by the ICRP for radon inhalation, specifies the assumptions and scientific data on which they are based, and discuss the associated uncertainties.

In 1993, the dose coefficients for exposure to radon and its progeny recommended in ICRP Publication 65 were 1.4 mSv per mJ h m-3 for workers and 1.1 mSv per mJ h m-3 for the public respectively. These coefficients were based on an epidemiological approach.

Taking the dosimetric approach into account, the ICRP recommends in its Publication 137 using a dose coefficient of 3 mSv per mJ h m-3 for workers in underground mines and in buildings in most situations. This dose coefficient also applies to public exposure situations in dwellings. For specific indoor work situations involving intense physical​ activity and for tourist caves, it recommends a dose coefficient of 6 mSv per mJ h m-3.

Download the report IRSN PSE-SANTE/2018-00002 « New dose coefficients for radon recommended in ICRP Publication 137 - Explanatory note » (PDF, 319 Ko)

Study on the implementation of linear accelerators coupled with a nuclear magnetic resonance imaging system in radiotherapy (MR-linacs)

Publication date: 16/11/2018

In the frame of the marketing of new radiation therapy devices coupling a linear electron accelerator to a magnetic resonance imaging system (MR-linac), the French Nuclear Safety Authority requested IRSN to provide a state of the art for this technology and to identify any points requiring vigilance.

IRSN's analysis relied on the expertise of the French Medical Physics Society, SFPM. The numerous observations and recommendations established by the IRSN/SFPM working group are synthesized in the advice published by the IRSN.

Download the study (PDF file)

Critical review: Epidemiological studies of leukaemia in children and young adults around nuclear facilities

Publication date: 22/04/2008

The German Federal Institute for Protection against Ionising Radiation made public a multi-site epidemiological study on 10 December 2007. This study covered 16 nuclear sites in Germany. The study meets the international scientific criteria.It establishes an excessive risk of leukaemia in children under five living within a radius of 5 km around German nuclear power plants.

The IRSN epidemiologist researchers have undertaken a critical review of all international scientific literature on the risk of leukaemia in children living near nuclear facilities.

Download the critical review summary (PDF file)

Evaluation guide for the radiological impact study of a basic nuclear installation (BNI) as a support for the authorization application of releases

Publication date: october 2002

At the time of a licence application of effluent releases and water pumping of basic nuclear facilities (BNF), the operator of the installation must in particular provide a radiological impact study of the radioactive effluent releases coming from the installation on the environment and on pubic health.

An impact study of the radioactive releases represents technical and conditional specifications. It was for this reason that the French Safety Authority (ASN then DSIN) and the Directorate-General of Health Services (DGS) requested IRSN (then IPSN), in April 1999, to develop a guide facilitating the review of such a study, as well for the services implied in the examination of the licence applications, as for all the concerned parties in this field.

The objective of the guide is to take into account the regulatory context which underlies the development of the impact studies (decree n°95-540 of May 4, 1995, modified by the decree n°2002-460 of April 4, 2002, and the Euratom guidline 96/29 of May 13, 1996, known as “the basic standard guideline”, accompanied by its transposition texts in French law).

In this precise context, the guide proposes to assess the radiological impact study of a BNF from three different angles:
- the description and the quantification of the produced effluents, by taking account of the triggering processes, of the different processing measures and of the procedures to optimise the reduction of the produced effluents;
- the estimate of the dosimetric impact of the planned releases on the population, taking into account the environmental characteristics of the installation;
- the definition of the conditions to monitor the releases and the environment.
This guide provides a general condition logical framework adaptable to any particular situation met.

Download the guide (PDF file)

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