ANALYSE DES DONNEES RELATIVES A LA MISE A JOUR DES NIVEAUX DE REFERENCEDIAGNOSTIQUES EN RADIOLOGIE ET EN MEDECINE NUCLEAIREMISSIONREPORT

2020

Analysis of data for updating
diagnostic reference levels inradiology and nuclear medicine
2016-2018 Report1

IRSN,ANALYSE DES DONNEES RELATIVES A LA MISE A JOUR DES NIVEAUX DE REFERENCEDIAGNOSTIQUES EN RADIOLOGIE ET EN MEDECINE NUCLEAIREFRENCH PUBLIC SERVICEEXPERT FOR NUCLEAR
AND RADIATION RISKS
Expertiser, rechercher, protéger, anticiper, IRSN’s mission includes providing expertise,partager ; telles sont les missions de l’IRSN au research projects, protection, planning for theservice des pouvoirs publics et de la population. future, and sharing resources to the benefit of
La singularité de l’lnstitut réside dans sa the French public authorities and the public at
capacité à associer chercheurs et experts pour large.
anticiper les questions à venir sur l’évolution et IRSN can boast the unrivalled capacity to combine
la maîtrise des risques nucléaires et the expertise of researchers and experts in order
radiologiques.
to plan ahead for the questions of the future
Les femmes et les hommes de l’IRSN ont à cœur about nuclear and radiological risks changes andde faire connaître leurs travaux et de partager how to control them.
leurs savoirs avec la société. Ils contribuent IRSN teams aim to ensure that society at large isainsi à améliorer l’accès à l’information et le aware of their works and can share theirdialogue avec les parties prenantes.
knowledge. With this approach, they help to
L’Institut concourt aux politiques publiques de improve a wide access to information and boostsûreté et sécurité nucléaires, de santé, dialogue with stakeholders.
d’environnement et de gestion de crise.

IRSN contributes to French public nuclear security
Établissement Public à caractère Industriel et and safety policies, as well as health,Commercial (EPIC), sous la tutelle conjointe du environmental and crisis management policies.
ministre chargé de l’Environnement, du ministre As a public industrial and commercial
de la Défense, et des ministres chargés de establishment supervised jointly by the Frenchl’Énergie, de la Recherche et de la Santé, l’IRSN Minister of the Environment, the French Minister
inscrit pleinement son action dans les politiques of Defence, and the French Ministers of Energy,
de modernisation de l’État avec sa démarche de Research and Health, IRSN comprehensively
management des risques et la mise en œuvre integrates its initiatives in the Government’s
d’une politique globale en matière de modernisation policies with its risk management
responsabilité sociétale.
approach and by implementing a CSR policy

IRSN has around

1,800 employees
including many engineers, doctors, agronomists, veterinarians, technicians, experts and researchers.
To carry out its work effectively, IRSN has abudget of some €280M
2

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTRESUMEEn application de la réglementation relative aux niveaux de référence diagnostiques (NRD - Décision
ASN n°2019-DC-0667), les établissements de radiologie et de médecine nucléaire doivent transmettre
annuellement à l’IRSN des données dosimétriques relatives aux examens d’imagerie dont ont bénéficié
leurs patients. Les examens faisant l’objet d’une évaluation sont choisis librement parmi la liste fixée
réglementairement. L’IRSN est chargé d’analyser ces données en vue de la mise à jour des valeurs des
NRD.
Depuis le 1er juillet 2019, la réglementation relative aux NRD a évolué. Les nouvelles dispositions
réglementaires s’inscrivent dans le contexte du renforcement des exigences relatives aux NRD au
niveau européen. Elles prennent en compte les recommandations internationales les plus récentes enmatière de NRD ainsi que les recommandations de l’IRSN émises dans ses précédents bilans. En
particulier, de nouvelles dispositions ont été introduites dans la réglementation en 2019 pour améliorer
le recueil et l’utilisation des NRD en pédiatrie.

Ce rapport présente les résultats de l’analyse des données recueillies sur la période 2016-2018. Ces
résultats ont été comparés aux valeurs de NRD en vigueur depuis juillet 2019 afin d’étudier la nécessitéd’une mise à jour.

Depuis 2014, la participation des professionnels à l’envoi de données apparaît comme stabilisée en
scanographie et en médecine nucléaire autour de 85%. Compte tenu d’une révision de l’estimation dunombre d’établissements réalisant des examens de radiologie conventionnelle, jusqu’à présent
fortement surévalué, la participation des professionnels de ces établissements est désormais évaluée à
50 %, contre 30 % précédemment. Elle reste faible.

Globalement, l’analyse des données recueillies sur la période 2016-2018 montre une diminution desvaleurs des indicateurs dosimétriques dans tous les domaines par rapport à la période précédented’analyse (2013-2015). La très grande majorité des valeurs se situe en dessous des NRD en vigueur
depuis le 1er juillet 2019 (de l’ordre de 0 à 25 %). Ce constat peut s’expliquer par deux raisons dont iln’est pas possible de dissocier les influences : les évolutions technologiques d’une part, etl’optimisation des protocoles et la sensibilisation des utilisateurs aux bonnes pratiques d’autre part.
Les écarts par rapport à ces nouveaux NRD restent cependant en général assez faibles et il ne paraît
pas nécessaire de réviser les valeurs de NRD à court terme. Concernant la pédiatrie, les données
transmises sont, comme par le passé, trop peu nombreuses sur ce bilan pour permettre une révision
des NRD à court terme.

Les résultats présentés dans ce bilan de « transition », suite à la publication de la décision ASN n°2019DC-0667, confirment le bien fondé de plusieurs évolutions réglementaires adoptées en 2019 :-le retrait de la dose à l’entrée (De) comme indicateur dosimétrique en radiologie
conventionnelle ;3

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT-

la suppression, du fait d’une pratique limitée, de la mammographie analogique ainsi que de 7
examens pédiatriques de médecine nucléaire de la liste des examens soumis au dispositif derecueil des NRD ;-la révision des valeurs de NRD associées aux différents examens soumis au dispositif de recueil
des NRD.

L’analyse des données recueillies sur la période 2016-2018, ainsi que l’évolution des pratiquesd’imagerie, conduisent l’IRSN à formuler plusieurs recommandations concernant le dispositif NRD :-en scanographie, faire évoluer la définition des NRD par région anatomique vers des NRD par
indication clinique. La définition actuelle des NRD par région anatomique conduit à agréger desdonnées hétérogènes car issues d’examens avec des objectifs cliniques divers. Sur la base derécents travaux aux niveaux national et européen, des NRD par indication clinique pourraientêtre définis et permettraient de disposer de valeurs spécifiques ;-en mammographie, les évaluations dosimétriques ne consistent pas en des relevés d’indicateurs
de dose déterminés sur des groupes de patients mais en des relevés d’un indicateur de dosemesuré sur fantôme lors du contrôle de qualité externe. Ainsi cette mesure peut se révéler
assez éloignée des doses réellement délivrées en pratique clinique. Du fait de l’évolution à
venir en 2021 des modalités de mesure de la dose moyenne à la glande lors des contrôles dequalité externes, une révision du NRD s’imposera. A cette occasion il conviendrait de repenser
la définition du NRD afin de la rendre plus pertinente vis-à-vis de la pratique clinique ;-ajouter la tomosynthèse mammaire à la liste des examens soumis au dispositif de recueil des
NRD ainsi que la technique d’imagerie volumétrique par faisceau conique (CBCT), en radiologie
dentaire, notamment pour les enfants ;-associer une évaluation des performances diagnostiques des appareils à la démarched’optimisation des doses délivrées aux patients afin de s’assurer que cette dernière ne nuisepas à la qualité de l’examen. En particulier si les valeurs médianes locales sont inférieures aux
valeurs guides diagnostiques récemment introduites réglementairement, la qualité d'image,plutôt que la dose, devrait être considérée en priorité dans le processus d'optimisation.

MOTS-CLES
Niveau de référence diagnostique, dose, activité administrée, radioprotection, exposition patient,radiologie, scanographie, médecine nucléaire

4

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTABSTRACT

Applying the diagnostic reference levels (DRL) regulations, healthcare facilities performing medical
imaging procedures are required to send samples of “patient” dosimetric data to IRSN each year. IRSN
is in charge of the analysis of this data in order to update the DRL values.
Since 1 July 2019, the DRL regulation has evolved. The new regulatory provisions are part of thestrengthening of DRL requirements at European level. They take into account the most recent
international DRL guidelines as well as IRSN previous recommendations. In particular, newrequirements introduced into the regulation in 2019 are intended to improve the collection and use of
DRLs in the pediatric field.

This report presents the results of the analysis of dosimetric data over the 2016-2018 period. Results
are compared to DRL values defined by the regulations in force since 1 July 2019.

Since 2014, the participation of professionals appears to be stabilized in CT and nuclear medicine
around 85%. It should be noted that, due to a revision of the estimate of the number of establishments
performing conventional radiology examinations which have so far been highly overvalued,
participation is now estimated at 50%, compared with 30% previously. This rate stays low compared to
CT and nuclear medicine.

The analysis of data collected over the period 2016-2018 shows an overall decrease in the values of DRL
quantities compared to the previous analysis period (2013 - 2015) for all modalities. The vast majorityof values are below the DRLs in force since 1 July 2019 (in the range of 0 to 25%). This observation canbe explained by two reasons from which it is not possible to separate the influences: technologicaldevelopments on the one hand, and protocols’ optimization and users’ awareness of good practices on
the other hand. Deviations from these new DRLs are generally quite small and there is no need torevise the DRL values in a near future. As in the past, the volume of collected data in pediatrics
remains too small to allow short-term NRD update.
The results presented in this “transition” report, following the publication of ASN resolution 2019-DC0667, confirm the legitimacy of several regulatory changes adopted in 2019:-

removing of the entrance surface dose (ESD) as a DRL quantity in conventional radiology;-

removing of screen-film mammography and 7 pediatric nuclear medicine examinations from the
DRL study list;-

update of examinations DRL values.

5

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTThe analysis of the data collected over the period 2016-2018, as well as the evolution of imaging
practices, leads IRSN to formulate several recommendations regarding DRL:-

in CT, modify the definition of DRL by anatomical region to DRL by clinical indication. The
current definition of DRL by anatomical region leads to the aggregation of heterogeneous datawith various clinical objectives. Based on recent works at national and European levels, DRL byclinical indication could be defined in order to get specific values regarding clinical objectives;-in digital mammography, dosimetric data are not determined on groups of patients but
measured on a phantom during external quality control. Thus, this measurement may be quite
different from the doses actually delivered in clinical practice. Due to upcoming changes inexternal quality control measurement of the average glandular dose, an adjustment of the DRL
will be required. It might be the occasion to rethink the definition of this DRL in order to makeit more relevant to clinical practice;-add breast tomosynthesis and the CBCT technique in dental radiology, especially for children to
the list of examinations submitted to the DRL regulation;-

associate diagnostic performance assessment to patient dose optimisation in order to ensurethat dose optimisation does not impair examination quality. In particular if median values arelower than regulatory achievable doses (ADs) values, image quality, rather than dose, should beconsidered as a priority in the optimisation process.

KEY-WORDS
Diagnostic reference levels, dose, administered activity, radiation protection, patient exposure,diagnostic radiology, computed tomography, nuclear medicine.

6

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTINTRODUCTION
This document presents the report on IRSN’s analysis of diagnostic reference levels data for the 2016-2018
period, in line with its mission under Article R.1333-61 of the French Public Health Code.

Diagnostic reference levels (DRL) were implemented in France in 2004 through the publication of a firstorder on DRLs in radiology and nuclear medicine (1). This order was based on the recommendations in
ICRP Publication 73 “Radiological Protection and Safety in Medicine” (2) and European Commission Guide
RP109 (3), with a view to optimising doses in line with the requirements of Council Directive
97/43/Euratom (4).
In 2011, DRL regulations were revised by the French Order of 24 October 2011 (5). Then following thevarious IRSN reports (6; 7; 8), the advisory committee for medical exposure (GPMED) to the ASN developed
recommendations on actions to improve the participation of imaging centres in collection of dosimetricdata, and the analysis thereof, at a national level, as well as on changes to DRL regulations (9; 10). This
work led to revision of the French DRL regulations launched in October 2015. Moreover, over the last few
years, DRLs have been a central concern for European and international bodies. The European Commission
funded a project on paediatric DRLs, PiDRL (11), which led to the publication of specific DRL guidelines for
paediatric imaging (12). The ICRP also published a report on DRLs in 2017 (13). This publication is anadditional source of both practical and methodological information and advice on these issues.
A new ASN resolution on DRLs (resolution 2019-DC-0667) (14) was approved by the French Order of 23 May
2019 (15) with a view to revising French DRL regulations. It takes into account most of therecommendations issued by IRSN in its previous reports (6; 7; 8), and aligns with the recent changes ininternational recommendations, in accordance with the reinforced DRL requirements set out in Council
Directive 2013/59/Euratom (16). The diagnostic reference levels concept is therefore evolving. DRLs arean essential and effective tool for optimising doses delivered to patients. They serve as dose indicators forthe quality of practices, and are intended to identify and monitor situations requiring improvement, andquantify the effectiveness of an optimisation approach. They should not be confused with “dose limits” or“optimum doses”.
The management of conventional radiology, CT and nuclear medicine facilities has to annually assess thedoses delivered to their patients during diagnostic procedures listed in the ASN resolution in force.
Analysing this data, in comparison of their median values with the current DRLs, should enableprofessionals to situate their practice against a national reference and undertake improvements in theevent that the value is over the DRLs without good reason. The recent introduction of achievable dosevalues (ADs)1 should also encourage the long-term optimisation of doses. Exposures which are particularly
low compared to the DRLs should be questioned, and any reduction in doses delivered shouldsystematically involve assessment of the quality of images obtained in order to prevent a drop in
diagnostic performance and any risk of performing unusable examinations. Once they have completed
their analysis, professionals have to submit the results of their dose assessments to IRSN.
IRSN is responsible for analysing the data submitted at a national level. It publishes a periodic report topresent data collection and analysis methods and results. This analysis enables IRSN to put forward
recommendations for updating the DRL regulations in order to improve their application and effectiveness.

1

ASN resolution 2019-DC-0667 pertaining to DRLs (14) provides professionals with a new level, designed tohelp set more ambitious goals than the DRL based on the 75th percentile. This new level is called“achievable dose”, and is defined as the 50th percentile (or median value) of distributions.

7

CONTENTS
COLLECTION AND ANALYSIS OF DIAGNOSTICREFERENCE LEVEL DATA ........................................................................... 9
CONVENTIONAL RADIOLOGY......................................................................23
COMPUTED TOMOGRAPHY ........................................................................35
NUCLEAR MEDICINE ................................................................................47
DRLs: PERSPECTIVES, SUMMARY AND RECOMMENDATIONS .................................57
CONCLUSIONS .......................................................................................61
GLOSSARY............................................................................................62
ANNEXES .............................................................................................64
REFERENCE DOCUMENTS ........................................................................ 133

FOCUS SECTIONSThe specific nature of paediatric DRLs ...................................................... 13
Satisfaction survey on DRL data collection methods ...................................... 16
Influence of detector type on patient exposure
in digital mammography ........................................................................ 32
Using clinical indications in computed tomography:
case of chest examination ...................................................................... 44
Influence of CZT technology on administered activities
for myocardial perfusion SPECT ............................................................... 54

8

COLLECTION AND
ANALYSIS OFDIAGNOSTICREFERENCE LEVELDATACONTENTS
WHAT’S NEW IN THE REGULATIONS
FOCUS
TYPE OF DATA COLLECTEDDATA COLLECTION
FOCUS
DATA ANALYSISPRESENTATION OF ANALYSIS RESULTS

WHAT’S NEW IN THE REGULATIONSThe French Decree of 4 June 2018 (17) transposingtherequirementsofCouncil
Directive
2013/59/Euratom into the Public Health Codeconfirmed IRSN’s missions regarding DRLs,
previously defined by the Order of 24 October 2011(5). In accordance with Article R.1333-61 of theFrench Public Health Code, for procedures which
present, by the doses delivered or by theirfrequency, a radiation protection issue forpatients, diagnostic reference levels (DRLs) areestablished. This DRLs are kept up to date by the
French Nuclear Safety Authority (ASN), taking into
account the results submitted to the FrenchInstitute for Radiological Protection and Nuclear
Safety (IRSN). IRSN is responsible for collecting andanalysing the data required for this periodic
update. To this end, it receives the results of dose
assessments from the operator or licensee. Figure 1
presents the principle for DRL implementation in
France, and the roles of the professionals,
authorities and IRSN.
IRSN had already put forward the following
recommendations
subsequent
toprevious
diagnostic reference level data analysis in radiology
and nuclear medicine:















10

reconsider data collection and DRL
definition methodology in paediatrics, inorder to remedy the lack of data submitted
to IRSN and supply professionals with DRLs
on which to base their work;
make DRL implementation obligations
proportionate to the size of institutions, inorder to avoid a situation in which someunits never undergo dose assessments;
analyse the data collected according totheir median value, rather than the meanvalue, in accordance with international
recommendations (12; 18);
defineastatisticalmeasurefor
optimisation (50th percentile) in addition to
the usual alert indicator (75th percentile);
revise DRLs: list of examinations to be
added or removed, numerical values (up or
down);
review dose values: remove entrance
surface dose (ESD) and add administeredactivity per body weighttake CT acquisition into account in nuclear
medicine;
include interventional radiology in thefields covered by the reference levels andmake the collection and analysis of data
mandatory, whenever possible setting
national reference levels;
introducefull
examinations
forconventional radiology and CT.

ASN resolution 2019-DC-0667 of 18 April 2019 on
DRLs (14), in force since 1 July 2019, takes into
account these recommendations and implements a
number of changes for the implementation of thecollection and analysis of DRL data compared to
the Order of 2011 (5).

Changes introduced by ASN resolution 2019DC-0667 (DRL)
Paediatrics
In paediatrics, the number of patients required has
been reduced to 10 patients (formerly 30 patients,
see focus below). Moreover, dose assessments havebecome mandatory if 5% or more of procedures are
performed on children (under 18s). The number of
paediatric procedures performed on a medical
device is assessed as a percentage of the total
activity performed on this device without limitation
to the procedures listed in the annex of theresolution. If the number of procedures performedin paediatrics is over 5% of the total activity for adevice, the activity manager must send data for aprocedure and weight range on the list in the annexof the resolution, and for at least 10 patients.
These modifications should improve the submissionof data in this specific field.
Number of dose assessments
The number of dose assessments required is now:


two per year and per device for computed
tomography and interventional radiology;
two per year and per department, with atleast one dose assessment per unit every
five years for conventional radiology.

These modifications make the implementation of
DRLs proportionate to the size of institutions while
avoiding a situation in which some units are neverassessed.

COLLECTION AND ANALYSIS OFDRL DATAMedian value
Data collected must now be analysed using themedian value for patient group doses rather than
the arithmetic mean. The results presented in thisreport are therefore expressed using median values
rather than mean values as in the previous report(see section on data analysis).
Achievable doses (ADs)
Achievable doses (ADs) have been implemented tosupplement DRLs. DRLs have not been enough toencourage long-term dose optimisation inradiography and computed tomography. It is likelythat in most cases, doses delivered could be
optimised and brought significantly under the DRL(75th percentile) through fairly simple and costeffective means, such as modifying acquisition
parameters (high voltage, collimation, current,
filtration, pitch, etc.). For example, an institution
with modern equipment which offers a number of
options for optimisation could set itself a more
ambitious target than the DRL in force and apply
the dose optimisation principle as much as
possible. This is why the decision was made toprovide professionals with an additional level which
would help them set more ambitious targets than
the 75th percentile DRL. This level is defined as the50th percentile (or median value) of distributions(Figure 10). As mentioned in ICRP Publication 135(13), if local median values are below the ADs,
image quality, rather than dose, should beconsidered as a priority in the optimisation process.
List of examinations and associated DRLs
The list of examinations and associated DRLs was
adjusted to take into account the report publishedin 2016 (8).

De was therefore removed. Only the DAP is used
now for dose assessments in this field. According to
the recommendations issued by the Heads of theEuropean Radiological Protection Competent
Authorities (HERCA) in 2012 (19), DAP should be
expressed in mGy.cm² and no longer cGy.cm²
Nuclear medicine
In nuclear medicine for adults:

the administered activity per body weight
has been added. This addition makes it
possible to focus on assessing the activity
to be administered with regard to patient
weight, while aiming to stay under thereference value for absolute activity.
PET/CT acquisitions now have a DRL.

Image-guided interventional procedures
Image-guided interventional procedures are now
covered, with the introduction of a DRL in theinterventional
field,
including
cardiology,
neuroradiology and vascular surgery. The DRLs
associated with these procedures are based on the
results of two studies conducted by the FrenchSociety of Medical Physics (SFPM) (20) and theFrench College of Hospital Cardiologists (CNCH)(21).
Full procedure
DRLs for a full paediatric radiology procedure (afull procedure consists of all radiography andradioscopy acquisitions performed) were added
under ASN resolution 2019-DC-0667. This is also thecase with DRLs for image-guided interventional
procedures, which have been defined for a fullprocedure including all radiography and radioscopy
acquisitions performed.

Body mass index
Adult patients must be selected according to bodymass index (BMI), which must be between 18 and
35 kg/m².
Conventional radiology
For conventional radiology, since the requirement
for units commissioned since 2004 to have a systemproviding information on the quantity of radiation
produced, the majority of units allow the user toassess patient exposure directly using dose area
product (DAP) data. In the report published by IRSN
in 2016 (8), a large majority of assessments wereusing data expressed in DAP (80 to 90% of datacollected) as opposed to data expressed in
entrance surface dose (ESD). The dose expressed inCommitment of departments and system
flexibility
In its last report (8), IRSN warned that thecommitment of departments and the use of DRLs
needed to be improved, in order to assess andoptimise doses delivered in imaging. IRSN also drewattention to the need to make the regulation
revision system more flexible for these technicalaspects, so it can respond better to changes inpractice and technologies. It is too early to say
whether the latest ASN resolution will have afavourable impact on these two areas.

11

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

Changes introduced by ASN resolution 2019DC-0660 (Quality assurance)
In its last report (8), IRSN recommended that the
DRL system be integrated into a broader quality
assurance approach for medical imaging. This has
now been implemented. ASN resolution 2019-DC0660 of 15 January 2019 established quality
assurance obligations for medical imaging using
ionising radiation. The collection and analysis ofdoses with regard to diagnostic reference levels
must now be covered by a formal process under
departments' quality management systems. This
formal procedure requirement also contributes tothe smooth running of the procedure optimisation
process.

Still to be done
DRLs by indication: for computed tomography, it
seems necessary to provide a DRL definition for
ALL
INSTITUTIONSWITHMEDICALIMAGING
UNITS

each organ and/or clinical indication. In thisregard, studies are currently underway in France(22) and Europe (23) with the goal of defining DRLs
by indication rather than anatomical area.
Device diagnostic performance assessment: IRSN
recommended that image quality assessment
should be systematically associated with dose
optimisation. This recommendation could not betaken into account in ASN resolution 2019-DC-0667,
and remains to be integrated into regulations.
Although the association of image quality with dose
optimisation is not covered by the regulations, this
aspect does need to be taken into account byprofessionals, who need to consider the quality ofimages obtained with regard to the dosesdelivered. In particular, if local median values are
below the AD, image quality, rather than dose,should be considered as a priority in the
optimisation process.

Internet application anddatabase

1) COLLECT dose data on patientgroups annually

COLLECTS, CHECKS andANALYSES data at national level
ORGANISES additional targetedstudies on specific practices(interventional radiology, cardiac CT
scans, paediatric imaging, etc.)

2) COMPARE their data to
DRLs and ANALYSE themand any reasons forexceeding the DRLSPUBLISHES periodic assessments:
4) SEND their data to IRSN

3) Implement an OPTIMISATION
approach

Analyses data at national
level, recommends andproposes DRL updates

AUTHORITIESREGULATE:
DRL field of application

List of examinations

Doses and DRL values

Figure 1: Principle for DRL implementation in France, and the roles of the professionals, authorities and IRSN.

12COLLECTION AND ANALYSIS OFDRL DATA

FOCUS
The specific nature of paediatric DRLs
Problems with implementation of paediatric DRLs
Since DRLs were implemented under French regulations in 2004, IRSN notes that the volume of data
received each year for paediatric examinations has been extremely low. Over and above the fact that
this presents a problem for updating DRLs, this data gap suggests that paediatric procedures are probably
subject to very little assessment. However, given the fact that children are more radiosensitive thanadults, particular attention needs to be focused on justifying and optimising procedures for them,especially when these examinations are likely to be repeated in treating some diseases. Defining
paediatric DRLs and their use by professionals for optimisation is therefore extremely important.
IRSN had already identified a number of causes for the low quantity of data received in earlier reports:

in general (with the exception of specialist paediatric imaging departments), paediatrics only
represents a low percentage of imaging professionals’ work. Paediatric data is therefore harder
to collect;segmentation by child weight or age group, which is absolutely essential for forming
morphologically homogeneous groups, further complicates data collection;
the French Order of 24 October 2011 set the minimum number of children per dose assessment at
30, as with adults;
the French Order of 24 October 2011 required professionals to select at least 2 examinations per
year for each imaging type, for adults or children.

A majority of professionals therefore preferred to focus on assessing adult examinations, for which it waseasier to recruit patients. Since 2004, only 11% of institutions that have submitted conventional radiology
data have sent paediatric data at least once. This proportion is 4% for computed tomography and 8% fornuclear medicine.
The problems encountered with paediatric DRLs in France are common to a number of countries, leading
the European Commission to launch the PiDRL (11) project in 2013, with a view to establishing European
DRLs for paediatrics. This led to the publication of European recommendations on DRLs for paediatricimaging in 2018 (12).
Solutions implemented for increasing the use of DRLs in paediatrics
Following IRSN‘s observations and proposals, ASN resolution 2019-DC-0667 amended regulations in order
to increase the assessment of paediatric procedures:

the minimum number of children to be included in a dose assessment was reduced from 30 to 10
in order to encourage collection in institutions that perform a low number of paediatricexaminations;one paediatric dose assessment is required every year if at least 5% of procedures performed
involve children.

This new regulation came into force halfway through 2019, but already seems to have had a positive
impact on the data collection for 2019 (not yet completed at the time of writing). Both the number of
institutions that have sent paediatric data, and the quantity of these data, have doubled in conventional
radiology and computed tomography, compared with previous years.
Furthermore, the increasing deployment of patient dose management system is contributing to solving
the problem of paediatric DRLs. By systematically recording DRL dose values used, it is making it easier tocollect and analyse data for the least common procedures, such as paediatric procedures.
Studies performed for updating and completing paediatric DRLs
Given the low quantity of data on paediatric examinations collected over the years, IRSN has organised
specific studies with imaging professionals in order to collect data for proposing a paediatric DRL update
and improve knowledge of practices.

13

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTThe first study was conducted with the French-speaking Society for Paediatric and Prenatal Imaging(SFIPP) and the French Society of Radiology (SFR) in 2016. Radiology departments that often perform
paediatric examinations, or specialise in paediatric radiology, were surveyed to collect data onradiography procedures, procedures with opacification and CT procedures. The study showed that,
despite the application of best practice, there was high divergence between participants with regard todoses delivered, especially for examinations with opacification. This confirms the importance of defining
DRLs for this type of procedure. The study results served as a basis for the paediatric DRL updates in 2019
and were published in two articles (24; 25).
The second study was conducted with the French Society of Nuclear Medicine (SFMN) and the FrenchSociety of Medical Physics (SFPM) in 2016-2017. All entities performing nuclear medicine examinations
were invited to send data for procedures performed on children. With regard to administered activities,
the study showed that practices were close to the DRLs in force, which are based on EANM
recommendations, and that there was no reason to change them. It also showed the importance of a DRL
for renal cortical scans. However, data for CT acquisitions on some examinations (PET and bone scans)were too few for it to be possible to determine associated DRLs. The results of the study were presented
at the 3rd French-speaking nuclear medicine days (26).

TYPE OF DATA COLLECTED
Depending on the imaging type, data are collected
for one or two DRL quantities:
●
●
●

●

dose area product (DAP) for conventional
radiology and orthopantomography;
average glandular dose (AGD) for digital
mammography;
volume computed tomography dose index(CTDIvol) and dose length product (DLP) forcomputed tomography;
total activity and administered activity per
body weight for nuclear medicine.

The result of the dose assessment is the medianvalue of 30 (or more) values collected from groupsof patients with the relevant dose values.
Patient morphology has a big impact on the dosedelivered. Regulations therefore require theirheight and weight to be recorded during dose
assessments.
In 2018, only 6% of dose assessments results
submitted to IRSN were assessed using the entrance
surface dose (see Figure 2). This represents lessthan 20 assessments received in 2018 for each14

examination, except for chest PA and pelvis AP
examinations for which around 30 assessments
were received. Withdrawal of this DRL quantity in
ASN resolution 2019-DC-0667 is therefore fully
justified.
In mammography and orthopantomography dose is
not assessed for a group of patients but with asingle measurement on phantom (AGD and DAP
respectively) performed during external quality
control (27; 28).
IRSN collects some parameters and information in
addition to DRL quantities, in order to check theconsistency of the data received:●●●for conventional radiology: high voltage,
filtration, focus-to-detector distance (FDD),
detector technology and size;for computed tomography: high voltage andpitch (in helical mode);for nuclear medicine: the radiopharmaceuticaladministered.

Moreover, additional analyses on these parameterswhich influence the dose delivered to the patient
may be performed.

COLLECTION AND ANALYSIS OFDRL DATA

Figure 2: Change in the percentage of radiology facilities submitting data in terms of entrance surface dose (ESD)
since 2006.

DATA COLLECTION
COLLECTION METHODS
Since 2011, IRSN has collected data over theinternet
using
an
IT
application(https://basenrd.irsn.fr). The system has improved
the quality of information submitted and facilitateddiscussions between IRSN and professionals, using
automatic checks during data entry.
In addition to its data entry and submissionfunctions, the DRL application offers professionals
the opportunity to compare their dose assessment

median values to the DRL in force, as soon as they
have finished entering their data. They can also
view their data submission history to improvemonitoring of the doses they deliver.
A satisfaction survey on DRL data collection
methods was sent to users in late 2018. The resultsof this survey are set out below in a special focus
section.

15

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

FOCUS
Satisfaction survey on DRL data collection methods
In November and December 2018, IRSN carried out a satisfaction survey on DRL data collection methods.
It covered the web application (https://basenrd.irsn.fr) used by professionals to submit their data, andthe contact and information channels available (telephone line, email, website, etc.).
The survey also provided an opportunity for users to suggest upgrades and improvements that would
make data reporting and monitoring easier.
Respondent numbers
Survey responses were anonymous. 352 individuals responded to the survey, representing around 16% ofquestionnaire recipients. The questionnaire was sent to people signed up on the DRL application with avalid email address in November 2018.
Table 1 shows respondent numbers. Most of them were radiographers (67%).
Over 80% of them had been using the application for at least 3 years.
The fields in which respondents worked are presented in Figure 3. This distribution is consistent with the
distribution of fields associated with application DRL accounts, except for computed tomography, whichis over-represented (52%, with only 33% of DRL accounts associated with a computed tomography device).
Number of
respondents
24

Distribution of
respondents (%)
6.8%

Other physician

2

0.6%

Dental Surgeon

5

1.4%

Radiographer

235

66.7%

Medical physicist

43

12.2%

Radiopharmacist

2

0.6%

Other (para)medical or technical profession

32

9.1%

Administrative professional (secretary, etc.)

9

2.6%

Total

352

100%

Radiologist / nuclear medicine physician

Table 1: Profession of individuals who responded to the survey

Conventional radiology
Mammography
Dental radiology
Computed tomography
Nuclear medicine

Figure 3: Distribution of responses by survey respondent field

Satisfaction regarding DRL application
For account creation and modification methods, 91% of respondents were satisfied or very satisfied withthe ease of use of the application in terms of account creation, and 97% of individuals were satisfied orvery satisfied with account validation lead times (see Figure 4).
Moreover, 98% of respondents were satisfied or very satisfied with DRL application availability.
For DRL data submission and validation, 89% of respondents were satisfied or very satisfied with ease ofuse of the application and 96% with submission validation response lead times (see Figure 5). Satisfaction
with exchanges with IRSN during the data validation phase received similar results (95% of respondents
were satisfied or very satisfied).
16

COLLECTION AND ANALYSIS OFDRL DATA

Finally, around 80% of respondents knew and used fairly regularly the application functions available(dose history and PDF printing of dose assessments).
Ease of use of application
Validation lead times

Unsatisfied

Very unsatisfied

Satisfied

Very satisfied

Figure 4: User satisfaction regarding account creation and modification

Ease of use of application
Validation or response lead time
Exchanges with IRSN during data
validation phase

Very unsatisfied

Unsatisfied

Satisfied

Very satisfied

Figure 5: User satisfaction regarding DRL data submission and validation methods (dose assessments)

Satisfaction regarding contact and information channels
Around 30% of respondents had used the dedicated DRL telephone line (+33 (0)1 58 35 70 77) and around
60% had used the dedicated DRL email address (nrd@irsn.fr). Around 95% of them on average weresatisfied or very satisfied with these services (see Figures 6 & 7).
IRSN also sends out emails several times a year to all DRL account holders to inform them of application
upgrades, remind them of deadlines, etc. Around 99% of respondents said they read these emails and findthem useful. 70% of them do not want these emails to be more frequent.
Finally, around 90% of respondents knew the DRL information website (http://nrd.irsn.fr). Some 98% of
these respondents were satisfied or very satisfied with the content of this website (regulatory reminders,
information on data submission, forms, datasheets).
Response times
WelcomeQuality of responses

Very unsatisfied

Unsatisfied

Satisfied

Very satisfied

Figure 6: User satisfaction regarding telephone line

Response time
Quality of responses

Very unsatisfied

Unsatisfied

Satisfied

Very unsatisfied

Figure 7: User satisfaction regarding email

17

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

Overall satisfaction and upgrade proposals
More generally, around 98% of respondents were generally satisfied or very satisfied with DRL datacollection by IRSN (application, relations with IRSN, etc.).
Dissatisfaction expressed generally related to the ease of use of the application for assessment validation
and account creation. With regard to account creation, some respondents did not like the fact that
account validation has to be performed using a paper form, and that this means a certain validation leadtime on the part of IRSN. For dose assessment validation, some respondents mentioned the timeconsuming process of writing out the data by hand, or difficulties submitting .csv files. Some respondents
would like there to be a simpler process using Excel spreadsheet data. Others also noted that theapplication is now somewhat dated, saying that they would like simpler more intuitive dashboards.
This feedback will be taken into account as much as possible in future application upgrades in order tomake it easier to use.
Two of the upgrades suggested by IRSN in the survey were particularly positively received byrespondents:-

graphical presentation of results and change in data over years;- a dynamic comparison of data to national data by examination type, and according to generation ofequipment, institution type, etc.
These aspects will also be taken into account in future application upgrades, from 2020, depending on
the possibilities for technical development.

DATA COLLECTION PERIODIn 2015, it was agreed with ASN that DRL
reporting periods would go from 2 to 3 years. This

report therefore presents an analysis of the datacollected for 2016, 2017 and 2018.

DATA ANALYSISDATA VALIDATION CRITERIA
Despite the automated checks performed by the
DRL application during data entry, some data
received by IRSN contain errors. Unrestrictive
automated checking criteria were selected for dataconsistency in order to avoid discouraging users
who might have their data refused.
Each assessment submitted by institutions ischecked by IRSN. Only data validated after
verification are used for performing national-levelstatistical analyses. The type of data required is
described in the Appendices.
For computed tomography, the complementary DRL
quantities combination, CTDIvol and DLP, can beused to check data consistency. The DLP/CTDIvol
ratio corresponds to the length exposed (length

18

examined plus additional radiation (overranging) at
the start and end of helical CT acquisition), which
is characteristic of the acquisition performed. This
makes it easy to identify, for example, a scan of
the sinuses among brain examinations or an
abdomen-pelvis acquisition in an assessment
labelled “chest-abdomen-pelvis”. Checking thisparameter is fairly discriminating, which explains
why there is a higher level of unused data than inconventional radiology. Figure 8 shows the
DLP/CTDIvol ratio median values for 3 patientheights: 160, 170 and 180 cm (+/- 2 cm).
During checks, if some patient data appears
inconsistent, the median values of the DRL
quantities are recalculated to exclude them.

COLLECTION AND ANALYSIS OFDRL DATA

Figure 8: Median values of exposed lengths (DLP/CTDIvol ratio) by examination and different heights for all CT data
received for the 2016-2018 period. The vertical line corresponds to the interquartile range (between the 25th and75th percentile).

SELECTION OF DATA FOR ANALYSIS
Despite the checks described in the preceding
section, validated dose assessments can containdata errors or data that is considered not torepresent current practices (abnormally high or low
DRL quantities, patient morphology, acquisition
lengths, etc.).
Data are therefore consolidated prior to analysis byapplying the following criteria:●

for adult examinations, exclusion of patients:o aged under 15;
o with a BMI of less than 18 or more than 35,
except for nuclear medicine;● for paediatric examinations, exclusion ofpatients:
o aged over 18;
o whose weight does not correspond to theselected category;● in computed tomography: exclusion of patient
examinations presenting particularly low orhigh acquisition lengths;● exclusion of data including less than 25
patients after application of the previously
cited validation and selection criteria.
The age limit for paediatrics varies between 15 and
18 depending on sources, so broader criteria havebeen applied. For adult examinations, patients in

the 15-18 age range have been accepted, since
they were likely to have been examined following
an adult protocol. For paediatric examinations,patients in the 15-18 age range have also been
accepted if their weight falls within a defined
category. It should be noted that selecting children
by weight category is more discriminating than age.
Since ASN resolution 2019-DC-0667 introduced apatient selection criterion based on their BMI, it
was decided that this criterion would be applied to
the 2016-2018 data retrospectively so that theresults of analyses, which are intended to direct
DRL updates, include this new requirement.
Implementation of BMI filtering is the reason forthe higher rates of unused assessments than inprevious reports (see the sections focused on thesedifferent fields).
However, the BMI criterion has not been applied
retrospectively to nuclear medicine data. In
practice, administered activities are defined either
as a function of weight, or independently of patientmorphology.
In adult conventional radiology and computed
tomography, in which the volumes of data received
are higher and the reduction in DRL quantities ismost marked, the 75th and 50th percentile values
19

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

have been calculated for each year, and it is the2018 values that are presented for potential DRL
updates. Nevertheless, all data (2016 to 2018) havebeen kept for producing the radiology andcomputed tomography histograms presented in the
Annex to this report.
In nuclear medicine, mammography, dental
radiology and paediatrics (all fields), the 75th and50th percentile values have been calculated for theentire 2016-2018 period, and not for each year
individually. This is for the following reasons:●●lower volumes of data received (paediatrics,
nuclear medicine);slower change in doses delivered (nuclear
medicine, mammography);

●

●

less
frequent
dose
assessments(orthopantomography, where data collection isassociated with a five-year quality check);the desire to perform analysis according todetector type used (mammography).

The fact that data collected over a 3-year period isbeing analysed means that several dose
assessments for a single examination from a single
unit are available for the period. In order to avoid
statistical bias linked to over-representation ofunits subject to several dose assessments over the
2016-2018 period, only the latest data received
have been kept for calculating the 75th and 50th
percentiles and presented in the histograms in the
Annex.

STATISTICAL MEASURES

From mean to medianNational DRLs were based on mean values (i.e.
arithmetic means) of the dosimetric data collected
for groups of 30 patients by professionals for each
unit. Professionals were required to compare thismean value to the DRL in order to assess theirpractice. The distribution of these unit meanvalues was analysed in order to determine the 75th
percentile.
For
severalyears
now,international
recommendations encourage use of the medianvalue to define a unit’s representative value,rather than the mean, both for comparison with
DRLs and for updating them (12; 13; 18; 29). This
recommendation was integrated into French
regulations by ASN resolution 2019-DC-0667.
What is the median?
The arithmetic mean of a series of values is equal
to the sum of the values divided by how many
there are. The median is defined as the central
value which divides the series of values into two
equal parts: half of the values are less than the
median, and the other half are greater than the
median. It also corresponds to the 50th percentileof the series (50% of values of a series are less than
the 50th percentile).
By convention, in this document, the term medianis used for a unit's representative dose value. For
the national distribution of unit median values, theterm 50th percentile will be used to define thestatistical measure used to establish the AD.

20

This convention also applies to nuclear medicine,where the national mean of mean unit activities
previously used is replaced by the 50th percentile(national) of median activities (per unit).
Why the median?
The arithmetic mean is highly impacted byabnormally high or low values. For DRL data, theseoutliers can represent very specific clinical cases(patient morphology, complexity, etc.), or errors
undetected during data collection and validation.
The median, however, is much less sensitive toextreme values (see Figure 9). Using the median istherefore more representative of an institution's
practice, and provides more relevant comparison
with the DRL. On a national scale, it also improves
the representativeness of DRLs, and given theinternational nature of the recommendation,
makes comparison between countries much more
relevant.
The previous IRSN report included an assessment of
the impact of switching from mean values tomedian values (8). It showed a drop of 75th
percentile values of around 5 to 10% with regard to
the values calculated based on means for radiology
and computed tomography. There is greater rangeof high values than low values (it is possible toperform examinations with a very high dose, but
not with a very low dose, and low doses will always
be greater than zero). In nuclear medicine,
switching from mean to median values leads todifferences of between –5% and +10% (8).

Figure 9: Comparison of mean and median values of DAP for a group of patients. The 3 outliers for patients 25, 27
and 29 increase the mean, making it less representative of the institution's general practice.

75th and 50th percentiles

Conventional
radiology
andcomputed
tomographyIn
conventional
radiology
andcomputed
tomography, the 75th percentile of the distributionof results (dosimetric data median values) of dose
assessments for a given examination define its DRL.
This is an alert level over which practices could beconsidered sub-optimal, or even abnormal, in termsof dose delivered to the patient. Given its
international use, it remains an essential measure
for DRLs.

Nuclear medicine
In nuclear medicine, the DRL was previously
defined as the mean of the mean values. The 50th
percentile of the median values is now used todefine the DRL.

75th percentile

Number of units

25th percentile

In addition, the 50th percentile of the dose
assessment results distribution is used to define the
AD mentioned in the “what’s new in theregulations” section (Figure 10).

Dose value
Figure 10: Definition of main statistical measures for dose data distribution for a given examination.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT75th to 25th percentile ratio

Previous IRSN reports showed that medical imaging
practices were involved high degrees of disparity,with patient exposure levels varying by several
orders of magnitude for an apparently similar
diagnostic performance.

Data heterogeneity is symptomatic of disparity inpractices. In order to assess it, the resultspresented in this report, as with the previous
report, are supplemented by a measure that isrepresentative of dispersion of values: the 75th to
25th percentile ratio.

PRESENTATION OF ANALYSIS RESULTS
The results of analyses performed by IRSN on thedata submitted by health professionals arepresented for each of the medical imaging fields
covered by the French Order of 24 October 2011 inforce during data collection between 2016 and2018:
conventional
radiology,
computed
tomography and nuclear medicine.
These results offer an assessment of theapplication of DRL regulations in establishments
performing medical imaging procedures, throughtheir participation in submitting data to IRSN.
The data breakdown submitted for the various
examination types is also analysed and comparedwith the frequency of the medical imaging
procedures in France. Although professionals had
the freedom to choose the examinations theyassessed from the list in the Order of 24 October
2011, this analysis assesses the representativenessof data collected with regard to national practices.
The results for paediatrics are separated fromthose for adults.
The percentage of data submitted for eachexamination out of all the data received by IRSN
for each imaging field is shown, together with theproportion of data that IRSN has been able to use.
Finally, analysis summaries are given in order toassess, for each examination, the positioning ofstatistical measures with regard to the DRLs inforce since 1 July 2019 and the results of theprevious report. The results for paediatrics are,once again, separated from those for adults.
Detailed analyses for each examination type arepresented in the Annex of this report.

22

The Annex includes the following for eachexamination where the amount of data collected
allows analysis, and per dosimetric value (DAP,
AGD, CTDIvol, DLP, activity and administeredactivity per body weight):●

national
distribution
graphsfor
dose
assessment results;● a table of the main statistical measures;● graphs presenting the change in the 75th and50th percentiles in radiology and computed
tomography, and the 50th percentiles in nuclear
medicine, since 2011.
During the 2016-2018 period, data was only
required to be assessed and submitted for the typesof examination listed in the Order of 24 October
2011. IRSN analyses therefore only cover these.
Nevertheless, ASN resolution 2019-DC-0667 restates
the previous lists, with additional elements. This
report provides updated values for the majority ofadult examinations, which have been calculated inline with the new methods in force since 1 July
2019 (median values, selection by BMI). However,in paediatric radiology and computed tomography,
a modification in patient weight categories meansthat the results obtained cannot be used to update
the DRLs for newly defined examinations. Equally,
data collection for the new examinations
introduced, including interventional radiology, only
began in July 2019. An overview of national
indicators will not be available until at least theend of 2020. Since this is a sector with fewer units
than for conventional radiology and computed
tomography, it will probably be necessary to wait
for several years of data in order to have data thatis sufficiently statistically robust.

CONVENTIONAL
RADIOLOGYCONTENTSCONTRIBUTION OF DEPARTMENTSDATA DISTRIBUTION BY EXAMINATION TYPE
SUMMARY OF RESULTS
FOCUS
SUMMARY
RECOMMENDATIONSANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTCONTRIBUTION OF DEPARTMENTS
For conventional radiology, the main institutions
involved in radiography procedures are:

the radiology departments of public andprivate healthcare institutions;private practices (radiology, pneumology,
rheumatology);
occupational
healthdepartments,
municipal healthcare centres, prison
healthcare departments, etc.;
dental practices.

(5100/3000). The participation rate for this report
can no longer, therefore, be directly comparedwith that of previous reports.

dentalFor the purposes of comparison with previous
participation rates, Figure 11 on the change inannual participation of institutions performing
conventional radiology procedures since 2004 has
been adapted to present the participation rates
determined using the number of institutions
estimated in 2005, and the number of institutions
estimated using linear regression between the 2005
and 2018 estimates.

The total number of conventional radiology
departments or practices needs to be estimated inorder to assess the contribution of departments.

Figure 11 shows that since 2016, around 50% of
institutions performing radiography procedures
have met DRL regulations. The participation rate
therefore seems to be stabilising over recent years.

Conventional
practices)

radiology(apartfrom

In previous IRSN DRL reports, this estimate wasbased on data provided by the French Nuclear
Safety Authority (ASN). The total number ofconventional radiology departments or practices
subject to DRL regulations – declared users of X-ray
generators for medical purposes who perform atleast one of the types of examination specified by
the DRL regulations – was then estimated at about
5,100 (excluding dental practices). This estimate
had not been updated since 2005, because thenational system for collecting information on
imaging equipment that is not subject toauthorisation is not strict enough, and numbers are
not well known.
In December 2018, IRSN attempted to review theestimate based on a telephone directory
extraction. This extraction used the key words“medical imaging”, “radiology”, “radiologist” and“hospital”. Extracted data was then consolidated inorder to remove any redundant entries.
In this way, the total number of conventional
radiology departments or practices was estimatedat around 3000 at the time of extraction. The total
number of departments and practices therefore
appears to have decreased by around 40% over 13
years, and was therefore probably over-estimatedin previous reports.
This new estimate impacts the participation resultsin the previous report by a factor of around 1.7

24

Please note that the 2011 dip in participation was
linked to the implementation of internet datasubmission that year. Furthermore, the clear dropin participation between 2014 and 2015 canprobably be attributed to stricter data collection
conditions for 2015 (data could be submitted up to
31 January 2015, as opposed to 31 March in 2014).
In conventional radiology, 73% of data come fromthe private commercial sector (Figure 13).
According to IRSN estimates, three quarters offacilities are private institutions, and a third are
public or non-profit institutions. Data source
distribution therefore seems consistent with
distribution of facilities and activity between the
public and private sector.
Dental practices
For dental practices, the increase of new accounts
on the DRL application, and therefore of practices
able to submit data, is presented in Figure 12. Overthe years, the number of new accounts isincreasing. It should be noted that by the end of
2019, around 35% of practices signed up between
2014 and 2018 had never submitted data.
Nevertheless, the very large increase (+75%) in thenumberofassessments
submitted
fororthopantomography examinations compared withthe 2013-2015 reports is noteworthy.

RADIOLOGY

Figure 11: Change in annual participation of institutions performing conventional radiology procedures since 2004.

Figure 12: Increase of new DRL application accounts for dental practices. Represents the number of new accounts fordental practices every year, and the proportion of those who had submitted data at least once by the end of 2019. At
end 2019, 336 dental practices had accounts and were able to send data to IRSN.

Figure 13: Source of data collected for conventional radiology DRLs, by examination type.

25

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTDATA DISTRIBUTION BY EXAMINATION TYPE
ADULT EXAMINATIONS
Figure 14 presents the distribution of dose
assessments results by examination type submitted
to IRSN from 2016 to 2018.
Procedure types are taken from the list in the 2011
Order, which goes unchanged in ASN resolution
2019-DC-0667. The percentage of data submitted
for each examination type is shown, together withthe proportion of data that IRSN has been able touse.
Paediatric procedures are covered in the next
section, and are represented in Figure 14 bycombining all examination types in order tomeasure the volume of paediatric data comparedto all conventional radiology data submitted.
Forallexamination
types,
exceptorthopantomography and mammography, the use
rate for submitted data is over 80%, and sometimes
around 90% (Figure 14). These rates are lower thanfor the previous report, primarily because entrance
surface dose (ESD) data have not been used. This
represented 7 to 9% of data received, depending on
the examination. Moreover, applying the new bodymass index (BMI) criterion (see data analysis
section) according to ASN resolution 2019-DC-0667
meant that a larger number of assessments were
rejected than for the previous report, which usedweight criteria for filtering data.
The use rate for orthopantomography is around70%, and 60% for mammography. These lower rates
are primarily due to the fact that identical datasubmitted several times over the collection period26

was not taken into account, as explained in the“data selection” section.
For screen-film mammography only 7 dose
assessments results from 4 different devices wereapproved (compared with 780 assessments
approved for mammography of all types). The
removal of this examination in the new resolution
is therefore fully justified, particularly given that
this examination has no longer been authorised fororganised breast cancer screening since February
2019.
As with the previous report, for adults, three
examination types represent around 50% of data:
chest PA, pelvis AP and lumbar spine AP. This
distribution seems consistent with the frequency ofradiography examinations performed in France(30).
Submission rates are virtually identical to theprevious report, apart from the abdomen AP whichdrops from 6 to 4.7%, thoracic spine AP which drops
from 4.1 to 3.5%, and orthopantomography whichrises from 2 to 5.1% due to the significant increasein the number of assessments submitted as
mentioned above.
The proportion of data for paediatrics is very low,with less than 2% of data submitted (184assessments out of a total of 10,343 assessments
submitted for the period), while around 10% ofprocedures in France are performed on children(30).

RADIOLOGY

Figure 14: Percentage distribution by examination type of radiography dose assessments for which results were
submitted to IRSN from 2016 to 2018 (total number of assessments submitted: 10,342).

PAEDIATRIC EXAMINATIONS
Figure 15 presents the distribution by examination
type according to the Order of 2011, for children,of dose assessments results submitted to IRSN by
professionals.

targeted paediatric studies in collaboration withprofessionals (24; 25). The results of these studies
were taken into account in ASN resolution 2019-DC0667.

The same 3 procedure types are still assessed mostfrequently: frontal chest for children of 10 (AP) and
20 kg (PA), and pelvis for children of 10 kg (AP),but the amount of data remains very low.

This ASN resolution makes dose assessments
mandatory if 5% or more of procedures are
performed on children (under 18s). These newprovisions should improve the amount of datasubmitted and enable more reliable analysis in thenext report. It is important to monitor this closely
and check the effectiveness of these newmeasures.

As for previous reports, the lack of paediatric data
presents a major difficulty for regularly setting andupdating DRLs. The recurrent nature of thisobservation led to the implementation of specificFigure 15: Distribution by examination type of the number of child radiography dose assessments for which results
were submitted to IRSN from 2016 to 2018 (total number of assessments submitted: 184).

27

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTSUMMARY OF CONVENTIONAL RADIOLOGY RESULTS
ADULT EXAMINATIONS

The results of the dose assessments submitted byconventional radiology professionals in terms of
DAP are presented in Table 2.

It shows:








the number of assessments used for 2018and 2016-2018 (N),patient median weight and BMI values,
the DRLs and ADs in force since 1 July 2019
(DRL and AD),the 75th percentile (75th) and 50th
percentile (50th) values for data collected
in 2018,
the 75th to 25th percentile ratio for 2018
the position of the 75th percentile for 2018with regard to the DRL in force since 1 July
2019 (% DRL),

the percentage of dose assessments data
received in 2018 over the DRL in force
since 1 July 2019 (> DRL)
and the 2018 75th percentile variation withregard to the 2015 value published in theprevious report.

All the data presented in Table 2 are for 2018. Only
the number of assessments used is given for 2018
and the 2016-2018 period (N).
Table 3 shows the results for orthopantomography
specifically (2016-2018 period).
Table 4 shows the results for mammography. These
results are discussed in a focus section.

Table 2: Summary of results of conventional radiology data analysis (excluding orthopantomography andmammography) by adult examination type, for 2018, expressed in terms of dose area product (DAP).

(2016-2018)

Medianweight(kg)

MedianBMI(kg/m²)

DRL

AD

P75

P50

Chest PA565 (1719)

70.0

24.6

200

150

185

Chest LAT

234 (684)

70.0

24.5

550

400

Abdomen AP

128 (410)

70.0

25.0

3400

2300

Pelvis AP

497 (1521)

70.0

25.0

3800

2750

Hip AP/LAT

217 (593)

70.0

25.2

1350

950

Cervical spine AP/LAT

224 (695)

70.0

24.7

400

250

Thoracic spine AP

82 (315)

70.0

24.7

1000

750

Thoracic spine LAT

30 (129)

68.3

24.5

1150

900

Lumbar spine AP

353 (979)

70.0

24.8

2700

1950

Lumbar spine AP

201 (580)

70.0

24.8

3900

2650

Examination typeN
2018

DAP (mGy.cm²)

P75/P25
ratio

% DRL

> DRL

Variation

118

2.40

-8%

20%

-1%

489

369

2.18

-11%

19%

-7%

3104

2118

2.02

-9%

18%

-8%

3437

2340

2.22

-10%

20%

-9%

1186

760

2.28

-12%

23%

-10%

325

219

2.71

-19%

16%

-9%

897

625

1.96

-10%

18%

-6%

1625

1021

2.46

+41%

47%

+43%

2405

1630

2.33

-11%

18%

-10%

3540

2200

2.34

-9%

19%

-9%

Table 3: Summary of results of orthopantomography data analysis for 2016-2018, expressed in terms of dose area
product (DAP).
Examination type

N

Orthopantomography

371

28

DAP (mGy.cm²)
DRL

AD

P75

P50

150

100

129

97

P75/P25
ratio

% DRL

> DRL

Variation

1.96

-14%

13%

-5%

RADIOLOGY
Table 4: Summary of results of mammography data analysis for 2016-2018, expressed in terms of average glandular
dose (AGD).
AGD (mGy)
Detector typeN

All digital detectors

P75/P25
ratio

% DRL

> DRL

Variation

1.26

1.45

-3.8%

19%

-2.5%

1.84

1.74

1.18

+15.0%

65%

+3.4%

DRL

AD

P75

P50

484

1.6

1.3

1.54

CR systems (photostimulable plate)

71

1.6

1.3

DR systems

413

1.6

1.3

1.40

1.21

1.35

-12.5%

12%+0.0%

Flat panel detectors

383

1.6

1.3

1.43

1.22

1.34

-10.6%

13%-

Photon-counting detectors

30

1.6

1.3

0.7

0.58

1.29

-56.3%

0%-

Detailed analyses by examination type arepresented in the Annex in sheets. For eachexamination type for which the data collected canbe analysed, these sheets show:● DAP distribution graphs for 2016-2018;● a table with associated statistical data;● changes in results since 2011.
Results show a drop of 1 to 10% in 75th percentile
values compared with 2015, except for the lateralthoracic spine (+43%). This is the examination forwhich the lowest number of dose assessments wereanalysed in 2018 (30 assessments), which casts
doubt on the representativeness of this result. The
value of the 75th percentile over the 3-year period
is 1275 mGy.cm², which is closer to the DRL inforce at 1 July 2019 (+10%) and is probably more
representative(129
assessments).
IRSN
recommends monitoring changes in the 75th
percentile for the lateral thoracic spine in coming
years, in order to determine whether a revision of
the DRL for this examination is required, orconsider whether it is still worth including it in thelist of examinations, given the low amount of datareported.
Apart from the lateral thoracic spine, the 75th
percentiles for 2018 are 8% to 19% under the DRLs
in force according to ASN resolution 2019-DC-0667,
which is based on 2015 values which had beenrounded up too much. Another revision of these
DRL values does not seem necessary in the short
term.
There is a high level of data dispersion, with a75th/25th percentile ratio of around 2 to 2.70. This
result raises questions about dose optimisation andassociated image quality. However, it is notpossible to discuss this result from the point ofview of image quality. As stated in the previous
report, the concept of image quality is complex,
and subjectivity makes it difficult to assess. It is anunderlying criterion that is not measured or taken
into account in the current DRL framework. As
stated above, an assessment of the diagnostic
performance of equipment needs to be associatedwith the system for optimising doses delivered topatients in order to ensure that it does notnegatively impact examination quality. In
particular, if local median values are below theachievable doses recently introduced in theregulations, image quality, rather than dose,should be considered as a priority in the
optimisation process.
The results of mammography data analysis (Table4) are discussed and detailed in a dedicated focus
section. This analysis leads IRSN to suggest
considering a change to the DRL concept for
mammography, in order to better analyse sites’
clinical practice and take into account the rapidly
growing technique of breast tomosynthesis.
Althoughnumbersoforthopantomography
assessments submitted are increasing, there arestill very few of them. In addition, external quality
controls, the results of which are used for dose
assessments, are performed every 5 years. It istherefore irrelevant to analyse 2018 alone. For thisreason, analysis was performed over 3 years (20162018), including for the 75th and 50th percentiles(Table 3).
In line with recommendations for breast
tomosynthesis, it could be useful to take into
account cone-beam computed tomography (CBCT)
for dental radiology, given the growing use of thistechnique and the sometimes high doses delivered,especially in paediatrics (31).

29

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTPAEDIATRIC EXAMINATIONS
The results of the dose assessment analyses for
paediatric radiology are presented in Table 5.

Order. They results show a 5 to 15% downward
trend compared with results for the 2013-2015
period.

For each weight category, this table shows thenumber of assessments used (N) for 2016-2018, theminimum, median and maximum weight ofchildren, the 75th percentile value (75th), the 50th
percentile value (50th) and the 75th to 25th
percentile ratio.

For chest examinations, results are over the DRL in
the 2019 resolution. This can be explained by adifference between the institutions included in the
study performed (24) for updating DRLs in the 2019resolution, and institutions represented in thenational DRLs. In the DRL update study, the vast
majority of institutions included were university
hospitals specialised in or used to paediatricradiology, while the institutions involved in thenational DRLs were more varied, including somemore general institutions. IRSN recommends
monitoring results on this examination in the next
few years. The change in regulations means that
more paediatric data is expected. They shouldmake it possible to check whether or not the 75th
percentile stays above the DRL. Depending on the
results for this examination with more data, it may
be appropriate to consider actions that willencourage centres to optimise practices and/or theneed to readjust DRLs.

As mentioned above, only frontal chest
examinations for children of 10 (AP) or 20 kg (PA)and frontal pelvis for children of 10 kg (AP) haveenough DAP data – over 20 assessments – and canbe analysed in detail (see Annex).
Comparison with the DRLs defined in ASN resolution
2019-DC-0667 is complicated by the fact that thechildweightcategories
forthevariousexaminations have changed from the Order of
2011. To aid comparison, Figure 16 shows the 75th
percentile value in terms of DAP for the 2016-2018
period, for abdomen, pelvis and chest examinations
by child weight and in comparison with the DRLs inthe 2011 Order and the 2019 ASN resolution.
With chest and pelvis examinations for children of
10 kg, results are slightly below the DRL in the 2011

Table 5: Summary of results of conventional radiology data analysis by paediatric examination type, in terms of dosearea product (DAP). (NB = newborns)
Examination type

AP
Chest
PA

Pelvis AP

Abdomen AP

30

Weight category(indicative age)N

3.5 kg (NB)
10 kg (1 y)

DAP (mGy.cm²)

Weight (kg)median

min

13

3.8

43

10.3

20 kg (5 y)22

30 kg (10 y)

P75/P25
ratio

Variation

max

P75

P50

3.0

4.7

9.7

7.0

3.23

-5%

6.9

14.5

19

13

2.66

-17%

18.3

16.0

20.0

43

28

2.15

-10%

8

28.3

25.5

30.9

35

29

2.55

+20%

10 kg (1 y)

24

7.2

5.7

10.5

29

19

2.63

-6%

20 kg (5 y)

6

18.9

16.5

20.5

85

76

1.86

-48%

30 kg (10 y)

6

29.2

28.0

30.0

171

154

1.24

-41%

20 kg (5 y)

8

20.0

17.5

21.9

196

87

2.93

-15%

30 kg (10 y)

4

29.8

29.0

30.0

272

200

2.15

-10%

RADIOLOGY

Figure 16: Comparison between the DAP 75th percentiles calculated for the 2016-2018 period and the regulatory DRL
values set in 2011 and 2019 for chest, pelvis and abdomen radiographs. For the 2019 DRLs, the points are placed in
the centre of the weight category intervals. Some 75th percentile values are calculated from very little data (chest
30kg, pelvis 20 and 30 kg, AXR 20 and 30 kg) and should therefore be used with care.

31

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

FOCUS
Influence of detector type on patient exposure in digital mammography
For mammography, the data submission rate has stabilised at 7.5% of conventional radiology assessments
submitted since 2015. Around 85% of data submitted are from digital radiography (DR) systems (including
flat panel detectors and photon-counting systems) and 15% are from computed radiography (CR) systems.
This distribution is consistent with the distribution of mammography units monitored under regulatory
quality controls by the French National Agency for Medicines and Health Products Safety (ANSM) (32).
Figure 17 shows the distribution of the average glandular dose (AGD) as a function of digital
mammography detector type, and Table 4 specifies the 75th percentile values associated with eachdetector type. For DR, photon-counting systems have been separated out from flat panel detector systems
in order to assess the impact of this difference on AGD.

Figure 17: Distribution of the average glandular dose (mGy) as a function of digital mammography detector type.

This analysis by detector type shows that the 75th percentile for assessments on CR systems is above the
DRL in force. More specifically, 65% of CR system assessments are over the DRL, as opposed to 13% for flat
panel DR systems. No assessment for photon-counting DR systems is over the DRL in force. Digitalradiography, and particularly photon-counting systems, remains the detection method involving the lowest
level of patient exposure.

32

RADIOLOGY

Optimisation of doses delivered to patients is even more important for mammography because this type of
examination is part of organised breast cancer screening. These dose data must not be decorrelated fromimage quality and breast cancer detection performance. French National Cancer Institute (INCa) surveys
from 2014 and 2017 on mammography performance as part of organised breast cancer screening show thatthe cancer detection rate was significantly higher with DR systems than with CR systems (33 ; 34). This is
despite the fact that CR mammography systems have moved from powder imaging plate technology toneedle imaging plates offering higher performance levels. CR detector systems therefore deliver higher
doses and offer lower performance in terms of cancer detection rates in organised screening programmes.
These results indirectly raise the question of technological obsolescence. It should, however, be specified
that cancer detection rates are not solely linked to the technology used, but also the clinical practice ofsites and the quantity of examinations performed for a specific method.
It should be noted that the AGDs submitted by centres are determined for an equivalent breast thicknessof 45 mm. This dose is measured by external control bodies during the annual external quality check for
40 mm Poly(methyl methacrylate) (PMMA) systems as defined by ANSM. The values submitted are
therefore not representative of the clinical practice of sites, but of system performance in given
conditions. For performance checks, the AGD delivered for 40 mm PMMA under the conditions defined by
ANSM must not exceed 2 mGy, or the unit is required to cease operations. This is why Figure 17 shows novalue over 2 mGy, and the 75th/25th percentile is fairly low in mammography. ANSM AGD measurement
methods have recently changed, and now require the use of polyethylene (PE) plates with the PMMA
plates, so the 45 mm equivalent breast thickness no longer applies. They will enter into force from 22
January 2021 (35). The current DRL for digital mammography will no longer be able to be used after thisdate. The DRL for digital mammography therefore needs to be revised before 22 January 2021. This
revision could offer an opportunity to consider changing the DRL concept for mammography, in order tobetter analyse sites’ clinical practice. Moreover, breast tomosynthesis is not covered by current DRL
regulations. The use of this technique is rapidly growing, and IRSN recommends that it be taken into
account in future mammography DRL updates.

33

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTSUMMARY
Analysis of conventional radiology dose assessments shows:
●
●
●

●
●
●

●

a stable radiology participation rate of around 50%;a distribution of examinations selected by professionals for dose assessments comparable to thefrequency of radiography procedures in France;
an overall decrease in the DAP 75th percentiles for all adult examinations except the lateral thoracic
spine (average 7% decrease since the previous report, excluding lateral thoracic spine examination
results);overall positioning of DAP 75th percentiles below the DRLs in force on July 2019 (8 to 19%) for all adultexaminations except the lateral thoracic spine;
significant data dispersion, with a 75th/25th percentile ratio of around 2 to 2.70;
in mammography: lower exposures for patients in units fitted with digital radiography detectors,
especially photon-counting systems; the current digital mammography DRL will no longer be able to be
used from 22 January 2021;
in paediatrics: a major lack of data; positioning of the DAP 75th percentile over the DRL in force on
July 2019 with regard to the frontal chest examination.

RECOMMENDATIONS
Analysis of conventional
recommendations:
●
●

●

●
●

34

radiology

dose

assessments

leads

IRSN

to

make

the

following

DRL updates are not necessary in the short term, except in mammography;
lateral thoracic spine: monitor change in the 75th percentile in coming years to prepare for a DRL
revision for this examination, or consider whether it is still worth including it in the list of
examinations;for mammography: the DRL needs to be revised before 22 January 2021. Plan to change the concept
for this DRL in order to better take into account clinical practice, and to add breast tomosynthesis tothe list of examinations;for dental radiology: add CBCT to the list of examinations, especially so as to be able to perform
paediatric monitoring;for paediatrics: add orthopantomography to paediatric examinations; monitor and assess theeffectiveness of measures taken to remedy the current lack of data; monitor the change in frontal
chest examination results in order to check whether the trend of the 75th percentile over the DRL
continues with more data, and understand why. Depending on results, implement actions that willencourage centres to optimise practices and/or readjust DRLs.

COMPUTEDTOMOGRAPHYCONTENTSCONTRIBUTION OF DEPARTMENTSDATA DISTRIBUTION BY EXAMINATION TYPE
SUMMARY OF RESULTS
FOCUS
SUMMARY
RECOMMENDATIONSANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTCONTRIBUTION OF DEPARTMENTS
The estimated total number of CT units covered by
ASN resolution 2019-DC-0667 (i.e. used for
diagnostic radiology) is 1,175 according to an IRSN
study in September 2017 (36). There are now 750
more scanners than in 2004. This development has
been taken into account by the various reports.
Some units are used for specific scanningtechniques (simulation in radiotherapy, hybrid
imaging in nuclear medicine), and do not fall within
the scope of application of DRLs for 2016-2018.
Scanning acquisitions performed in positronemission tomography (PET) examinations haverecently been included in the field of application of
DRLs under ASN resolution 2019-DC-0667. This
resolution came into force on 1 July 2019, and thedata for these examinations are not covered by this2016-2018 report.

36

Dose assessments were submitted for around 85% ofunits in 2018. Participation seems to have beenstable at around 80-85% for the last six years(Figure 18).
In computed tomography, distribution of data
sources is balanced between the public sector andthe private commercial sector (Figure 19), except
for the special case of paediatrics. This data source
distribution is consistent with the distribution of
scanners between the public and private sectors,
which is fairly well known. From the 2015 DGOS
data contained in the report by the Cour desComptes published in 2016 (37), the proportion of
public sector CT scanners can be estimated ataround 47%.

COMPUTED TOMOGRAPHY

scanographie

Figure 18: Change in annual participation of institutions performing computed tomography procedures since 2004.

Figure 19: Source of data collected for computed tomography DRLs, by examination type.

37

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTDATA DISTRIBUTION BY EXAMINATION TYPE
ADULT EXAMINATIONS
Figure 20 shows the distribution of dose
assessments submitted by professionals per
examination type, in line with the list defined by
the 2011 Order. It gives the percentage of dose
assessments submitted for each examination,
together with the proportion of data that IRSN has
been able to use.

number of dose assessments are the brain, followedby the abdomen-pelvis region and the chest. The
lumbar spine examination is also well represented.
The chest-abdomen-pelvis examination is the least
represented.
This distribution is consistent withcomputed tomography activity (30).

national

As with the observations of the previous IRSN
report in 2016, the examinations with the greatest

Figure 20: Distribution by examination type of computed tomography dose assessments for which results were
submitted to IRSN from 2016 to 2018 (total number of assessments submitted: 5,860).

In total, around 80% of computed tomography datasubmitted to IRSN have been used for national
analysis, while the two previous reports have had astable rate of around 90%. The rejection rate is 5
to 10 points higher depending on the anatomicalzones considered in this report than in the reportpublished in 2016. This increase is due to theapplication of the new body mass index (BMI)
criterion.
The brain examination remains the clinicalindication with the lowest rejection rate38

(around 9%) because the BMI criterion does not
apply. The chest-abdomen-pelvis region has thehighest rejection rate (around 30%). This rejection
rate can be explained by the application of theacquisition length validation criterion, as stated in
the section on data validation criteria. It is not
unusual for dose assessments submitted to containdata from abdomen-pelvis or chest-abdomen
acquisitions in a chest-abdomen-pelvis procedure.

COMPUTED TOMOGRAPHY

scanographie

PAEDIATRIC EXAMINATIONSThe number of paediatric CT assessments is still
very low, accounting for less than 2% of all CT
examinations (Figure 20), and only seventeen dose
assessments per examination type and weightcategory (Figure 21). As in the previous assessment,
brain and chest examinations are most frequently
subject to dose assessments. There is not always
sufficient data to assess practices on a national

level. As stated above, ASN resolution 2019-DC0667 now makes dose assessments mandatory if 5%
or more of procedures are performed on children(under 18s). These new provisions should improve
the amount of data submitted and enable morereliable analysis in the next report. It is important
to monitor this closely and check the effectivenessof these new measures.

Figure 21: Distribution by examination type and weight of the number of child CT dose assessments for which results
were submitted to IRSN from 2016 to 2018 (total number of assessments submitted: 91).

39

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTSUMMARY OF COMPUTED TOMOGRAPHY RESULTS
ADULT EXAMINATIONS
Tables 6 and 7 show the results of analyses of adultcomputed tomography data collected between
2016 and 2018, by examination, in terms of CTDIvoland then DLP.
They show:•
the number of assessments used for 2018and 2016-2018 (N),•median weight and BMI values for patientsassociated with the collected data,•
the DRLs and ADs in force since 1 July 2019
(DRL and AD),•the 75th and 50th percentile values for thedata collected in 2018,•

the 75th to 25th percentile ratio for 2018,•
the position of the 75th percentile for 2018with regard to the DRL in force since 1 July 2019(% DRL),•the percentage of dose assessments
received in 2018 over the DRL in force since 1 July
2019 (> DRL)•
and the 2018 75th percentile variation withregard to the 2015 value published in the previous
report.
All the data presented in Tables 6 and 7 are for2018. Only the number of assessments used is given
for 2018 and the 2016-2018 period (N).

Table 6: Summary of adult computed tomography analyses, by examination, for 2018 data, in terms of CTDIvol.

(2016-2018)

Medianweight(kg)

MedianBMI(kg/m²)

DRL

AD

P75

P50

Brain

422 (1284)

70.0

24.7

46

40

41.0

Chest

337 (1007)

71.0

24.9

9.5

7.5

Chest-abdomen-pelvis

207 (591)

70.0

24.7

11

9.5

Abdomen-pelvis

354 (963)

72.0

25.1

13

11

Lumbar spine

298 (858)

72.0

25.4

28

23

Examination type

N
2018

CTDIvol (mGy)

P75/P25
ratio

% DRL

> DRL

Variation

37.0

1.21

-11%

11%

-10%

7.5

6.3

1.56

-21%

6%

-18%

10.1

8.5

1.34

-8%

15%

-7%

10.1

8.9

1.35

-22%

3%

-18%

24.1

20.7

1.35

-14%

9%

-11%

Table 7: Summary of adult computed tomography analyses, by examination, for 2018 data, in terms of DLP.

(2016-2018)

Medianweight(kg)

MedianBMI(kg/m²)

DRL

AD

P75

P50

Brain

422 (1288)

70.0

24.7

850

725

742

Chest

337 (1010)

71.0

24.9

350

275

Chest-abdomen-pelvis

207 (592)

70.0

24.7

750

650

Abdomen-pelvis

354 (966)

72.0

25.1

625

Lumbar spine

298 (860)

72.0

25.4

725

Examination type

40

N
2018

DLP (mGy.cm)

P75/P25
ratio

% DRL

> DRL

Variation

675

1.21

-13%

10%

-11%

286

240

1.58

-18%

7%

-16%

689

598

1.34

-8%

14%

-7%

525

492

430

1.36

-21%

4%

-19%

625

654

564

1.38

-10%

13%

-9%

COMPUTED TOMOGRAPHY
The 75th percentiles for 2018 in terms of CTDIvol and
DLP are below the DRLs in force since 1 July 2019by 8 to 22% for all examinations considered. They
are closer to the AD than the DRL.
The CTDIvol and DLP have also dropped by 7% to 19%
for all examinations compared with the previous
report.
The quantity of data collected for the 2016-2018
period is satisfactory, because hundreds ofassessments were submitted for each examination
type.
Detailed results for each examination type for the
2016-2018 period are shown in the report Annex.
The figures presenting the change in CTDIvol and
DLP since 2011 show a continuous reduction of the75th percentiles, for all examination types. DRL
quantities are continuously dropping.
Lumbar spine:
For the lumbar spine, in the 2016 report (7), the75th percentile in terms of DLP was 9% over the DRL
set by the Order of 24 October 2011. Since this DRL
was reviewed upwards in ASN resolution 2019-DC0667, the 75th percentile in terms of DLP for the
lumbar spine is now under the DRL in force andclose to the AD as with other anatomical regions.
Abdomen-pelvis:
For the abdomen-pelvis, the 2018 75th percentiles
for CTDIvol and DLP are even below the AD.
Moreover, the downward evolution of DRL
quantities for this region seems more marked thanscanographie
for the brain, for instance. This downward trend
could be explained by technological developments,
and particularly the widespread use andimprovement of iterative image reconstruction
algorithms. This type of algorithm is more effectiveon the abdomen-pelvis region than on the brain, so
this seems a plausible explanation for the resultspresented in the Annex.
As with conventional radiology, the computed
tomography DRLs were recently revised with ASN
resolution 2019-DC-0667 that came into force on 1
July 2019. The differences between the 75th
percentiles and the DRLs in force are therefore lessmarked than in the 2016 report (8). They do notappear to need revising again in the near future.
However, it should be recalled that new DRLs havebeen established on the basis of data from 2015.
Given the downward trend observed in dose
assessments for the short period of 2016-2018, they
will need to be monitored closely.
Moreover, as shown in the focus section, defining
DRLs by anatomical region leads to combining datathat is very heterogeneous because they present
significantly varying clinical objectives. Computed
tomography DRLs could be updated for clinicalindications. To this end, device diagnostic
performance assessment should be taken into
account in the DRL framework in order to be able
toensurethattheexamination
qualityrequirements associated with delivered doses arecomplied with.

41

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTPAEDIATRIC EXAMINATIONS
Table 8 shows the results of analyses of datasubmitted in terms of CTDIvol and DLP for thepaediatric computed tomography examinations
defined in the 2011 Order. The table shows thenumber of assessments used (N), the median,minimum and maximum weights of patientsassociated with the data collected, the value of the75th percentile, the value of the 50th percentile andthe 75th and 25th percentile ratio. All data is for the
2016-2018 period. Only the 75th and 50th percentile
values and the 75th/25th ratio are for 2018.
Apart from the brain (10 and 20 kg) and chest (20kg), there are too few assessments (< 10) to beable to discuss results.
Comparison with the DRLs defined in ASN resolution
2019-DC-0667 is complicated by the fact that thechildweightcategories
forthevariousexaminations have changed from the Order of

2011. To aid comparison, Figure 22 shows the 75th
percentile value in terms of DLP and CTDIvol, forthe 2016-2018 period, for brain and chest
examinations by child weight and in comparison
with the DRLs in the 2011 Order and the 2019 ASN
resolution.
For brain (10 and 20 kg) and chest (20 kg), none ofthe dose assessments submitted are over the DRL
set in the 2011 order in terms of CTDIvol. Figure 22
shows that the results for the 2016-2018 period areslightly over the DRLs set in the 2019 resolution, inparticular in terms of DLP for the brain
examination. These values have been recently
adapted with the introduction of ASN resolution
2019-DC-0667 on the basis of a study (25)presented in a special focus section, and it is too
early to suggest DRL adjustments.

Table 8: Summary of child computed tomography analyses, by examination, for 2018 data, in terms of CTDIvol and
DLP.
Examination type

Brain

Facial bones

Petrous bone

Chest

Abdomen-pelvis

42

Weight category(indicative age)

Weight (kg)N

CTDI vol (mGy)median

min

max

P75

P50

P75/P25

ratio

DLP (mGy.cm)
P75

P50

P75/P25

ratio

10 kg (1 y)

11

10.0

8.0

12.0

21.3

19.8

1.18

390

325

1.26

20 kg (5 y)

12

18.8

16.0

20.5

26.7

24.1

1.25

479

448

1.12

30 kg (10 y)

5

29.0

28.0

30.0

29.4

25.5

1.28

558

520

1.17

10 kg (1 y)

0

20 kg (5 y)

1

20.0

20.0

20.0

7.9

7.9

1.00

142

142

1.00

30 kg (10 y)

1

35.0

35.0

35.0

10.5

10.5

1.00

193

193

1.00

10 kg (1 y)

2

10.4

10.0

10.8

30.7

30.70

1.00

146

142

1.05

20 kg (5 y)

5

19.0

19.0

21.0

43.9

43.9

1.04

290

231

1.34

30 kg (10 y)

2

29.5

29.0

30.0

61.5

56.7

1.19

260

259

1.01

10 kg (1 y)

9

10.3

9.0

12.5

1.10

0.94

1.25

31.2

19.5

1.84

20 kg (5 y)

10

20.0

16.6

22.5

1.30

1.21

1.27

33.3

31.2

1.30

30 kg (10 y)

4

29.3

28.5

30.0

1.93

1.72

1.29

57.1

51.8

1.22

10 kg (1 y)

0

20 kg (5 y)

2

19.0

18.0

20.0

1.79

1.63

1.23

59

56

1.12

30 kg (10 y)

2

29.3

28.5

30.0

3.14

2.93

1.16

145

133

1.19

COMPUTED TOMOGRAPHY

scanographie

Figure 22: Comparison between the CTDIvol and DLP 75th percentiles calculated for the 2016-2018 period and theregulatory DRL values set in 2011 and 2019 for child brain and chest CT scans. For the 2019 DRLs, the points areplaced in the centre of the weight category intervals. Some 75th percentile values are calculated from very little
data (chest 10 and 30 kg, brain 30 kg) and should therefore be used with care.

43

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

FOCUS
Using clinical indications in computed tomography:
case of chest examination
An SFPM working group that IRSN was part of recently studied doses delivered in computed tomography byclinical indication, and established significant differences for some anatomical regions depending on theindication, in particular the chest, in an article entitled “Patient dose evaluation in computed
tomography: A French national study based on clinical indications” published in 2019 (22).
The working group analysed four groups of clinical indications for the chest: a) pulmonary embolism; b)chronic obstructive pulmonary disease (COPD), emphysema, and pneumothorax; c) infectious diseases andpneumonia and finally d) examinations to find pulmonary metastases. Figure 23 shows the distribution of
volume computed tomography dose indices (CTDIvol) for each group of indications for single acquisition
examinations and BMI patients between 18.5 and 25 kg/m². There were significant differences, especiallybetween the pulmonary embolism (a) and COPD (b) groups.
It is interesting to compare the results of the SFPM working group study with the results obtained byanalysis of the data submitted to IRSN. For the chest, for example, data submitted to IRSN and presented
in this report produce a median DLP of 240 mGy.cm, while in the SFPM study, median DLPs for patientswith BMIs of between 18.5 and 25 kg/m² varied from 112 mGy.cm for COPD or pneumothorax
examinations, to 203 mGy.cm for pulmonary examinations (Table 9).
This difference in results can be explained by a number of factors: the way in which the clinical indication
is taken into account in the SFPM study, and the composition of the sample of institutions that took part inthis study. Private institutions account for only 4% of institutions included in the SFPM study, whereas theyaccount for 51% of institutions that submitted data to IRSN. This could explain the lower DLP values
obtained in the SFPM study. A medical physicist was involved in most institutions included in the SFPM
study, which leads us to assume that procedures are better optimised there.
This difference in results by clinical indication and the difference in the type of institution concerned are
an excellent illustration of the advantages and disadvantages of implementing DRLs on a national scale.
The organisation implemented for data collection has the advantage of offering good representation of
institutions at national level. However, DRLs by anatomical zone cannot be used to distinguish between
results on the basis of clinical indications. For example, as the SFPM study shows, pulmonary embolism is avery common indication, and it accounts for the chest examination that delivers the highest dose.
However, COPD, emphysema and pneumothorax indications have lower image quality requirements andtherefore involve lower doses. Setting DRLs for these clinical indications, for example, would make itpossible to encourage institutions to establish specific protocols, if that is not already the case, andimprove optimisation of doses delivered to patients.
The SFPM study results suggest that it could be possible to establish DRLs per clinical indication.
Expectations for different indications are genuinely different, so implementing DRLs for indications could
have a significantly positive impact on dose optimisation.
As mentioned in the previous report, the assessment and optimisation process for the dose delivered topatients within the DRL framework must not impair examination quality. This is an underlying criterion
that needs to be taken into account in the DRL framework, particularly with a view to changing over toclinical indication DRLs in order to be able to check whether the image quality requirements associatedwith doses delivered are complied with.

44

scanographie

CTDIvol (mGy)

COMPUTED TOMOGRAPHY

Figure 23: Distribution of CTDIvol values for 4 chest examinations (single acquisition) and patients with BMIs between
18.5 and 25 kg/m²: pulmonary embolism (Chest/PE), chronic obstruction or pneumothorax (Chest/COPD), infectious
diseases or pneumonia (Chest/Infectious) and examinations to find pulmonary metastases (Chest/Metastases) (credit
SFPM)

Examination typeN

Chest/COPD
Chest/PE
Chest/Infectious
Chest/Metastases

61
229
60
93

DLP (mGy.cm)
P50
P75
112
185
203
291
145
227
137
196

P75/P25
ratio
2.4
2.1
2.1
1.9

Table 9: results of SFPM study in terms of DLP (mGy.cm) for 4 chest examinations: pulmonary embolism (Chest/PE),chronic obstruction or pneumothorax (Chest/COPD), infectious diseases or pneumonia (Chest/Infectious) andexaminations to find pulmonary metastases (Chest/Metastases) (credit: SFPM)
Figure and table reproduced with the permission of SFPM

45

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTSUMMARY
Analysis of computed tomography dose assessments shows:
●
●
●
●
●

a stable computed tomography institution participation rate of around 80% of facilities since 2013,reaching 85% in 2017 and 2018;a distribution of examinations selected by professionals for dose assessments comparable to thefrequency of CT procedures in France;a regular decrease in the 75th CTDIvol and DLP percentiles for all examinations (average around 12%
since the last report);
overall positioning of CTDIvol and DLP 75th percentiles closer to the AD than the DRLs in force since 1
July 2019 for adult examinations;a major and ongoing lack of data in paediatrics;

RECOMMENDATIONS
Analysis of computed tomography dose assessments leads IRSN to make the following
recommendations:
●
●
●
●

46

DRL updates are not necessary in the short term, but they should continue to be monitored;
plan for computed tomography DRL updates to take into account clinical indications;associate diagnostic performance assessment of equipment with the patient dose optimisation system;
for paediatrics: monitor and assess the effectiveness of measures taken to remedy the current lack ofdata.

NUCLEAR MEDICINECONTENTSCONTRIBUTION OF DEPARTMENTSDATA DISTRIBUTION BY EXAMINATION TYPE
SUMMARY OF RESULTS
FOCUS
SUMMARY
RECOMMENDATIONSANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTCONTRIBUTION OF DEPARTMENTS
Nuclear medicine departments were surveyedbased on the French Society of Nuclear Medicine
and Molecular Imaging (SFMN) directory of nuclear
medicine departments and the information
published by ASN. There were 231 nuclear medicine
departments listed in late 2015, and 236 in late2017, fitted with 162 positron emission tomography(PET) scanners and around 475 gamma cameras(38).
Figure 24 presents the change in the number ofnuclear medicine departments that submitted dose
assessment results for 2004 to 2018.

In nuclear medicine, the distribution of data
sources is balanced between the public sector andthe private commercial sector (Figure 25), except
for the special case of paediatrics and brain
perfusion. This data source distribution isconsistent with the distribution of facilities
between the public and private sector (38). For
paediatrics and brain perfusion, data comesprimarily from the public sector. This could be
explained by the specific nature of this type of
examination and a low data submission rate
(Figure 25).

Participation has stabilised since 2014, with around
90% of departments having submitted data.

Figure 24: Change in annual participation of institutions performing nuclear medicine procedures since 2004.

48

NUCLEAR MEDICINE

Figure 25: Source of data collected for computed DRLs, by examination type, in nuclear medicine.

DATA DISTRIBUTION BY EXAMINATION TYPE
ADULT EXAMINATIONS
Figure 26 shows the distribution of dose
assessments submitted by nuclear medicine
professionals to IRSN by examination type, in linewith the list in the Order of 24 October 2011. It
gives the percentage of dose assessments
submitted for each examination, together with theproportion of data that IRSN has been able to use.
Paediatrics is shown for all examinations in order toshow the volume of paediatric data by comparison
with all data submitted for nuclear medicine. It isdetailed in the next section.
Since 2004, the examination which regularly has
the biggest number of dose assessments has beenbone scanning. The number of assessments for 18FFDG PET has increased 3 points since the previous
report, which is consistent with the increase in thenumber of these devices. Myocardial perfusion
SPECT (99mTc), lung perfusion and thyroid (99mTc)
scans have been assessed in similar proportions to
2013-2015. The distribution of data by examinationis consistent with the frequency of examinations
performed in France in 2012 (30).

By examination, the data use rate for the 20162018 period varies between 75% and 87%, except
for bone and 18F-FDG PET scans (66%). The unused
data submitted are almost exclusively redundantdata (identical examination type and unit type).
For statistical reasons and in order to avoid overrepresentation of some institutions, only the mostrecent dose assessment was taken into account forcalculating the national indicators. This isparticularly the case for bone scans and 18F-FDG
PET, the examinations for which the most data isreceived. Moreover, for the PET scan, somemachines are managed by legal entities dedicatedto this activity who submit data for thisexamination every year. Repeating assessments forthe same examination over a 3-year period can still
be useful for centres for monitoring dosesdelivered.
It should be noted that for the 2016-2018 period, alittle over 90% of nuclear medicine departmentsthat do not exclusively perform PET examinations
performed a bone scan dose assessment.

49

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

Figure 26: Distribution by examination type of nuclear medicine dose assessments for which results were submitted
to IRSN from 2016 to 2018 (total number of assessments submitted: 1373).

PAEDIATRIC EXAMINATIONS
The volume of assessments submitted for
paediatric nuclear medicine is very low, accounting
for less than 3% of all data (Figure 27). This number
has dropped by around 30% compared to the 20132015 report. A detailed breakdown of the datasubmitted is shown in Figure 27.
There is not enough data to properly assess
practices at a national level. As stated above, ASN
resolution
2019-DC-0667
now
makes
dose
assessments mandatory if 5% or more of proceduresare performed on children (under 18s). These newprovisions should improve the amount of datasubmitted and enable more reliable analysis in thenext report. It is important to monitor this closely
and check the effectiveness of these newmeasures.

Out of the 10 examinations (without taking weightcategory into account) listed in the 2011 Order,
dose assessments were not performed for 6 of
them:







lung perfusion scan
thyroid scan with 99mTc
radionuclide ventriculography
dynamic renal scan with DTPA
brain perfusion SPECT with ECD
brain perfusion SPECT with HMPAO

Moreover, just one institution submitted data
for thyroid scans with iodine 123.
The recent removal of these 7 examinations in
the new resolution is therefore fully justified.

Figure 27: Distribution by examination of the number of child nuclear medicine dose assessments for which results
were submitted to IRSN from 2016 to 2018 (total number of assessments submitted: 31).

50

NUCLEAR MEDICINESUMMARY OF NUCLEAR MEDICINE RESULTS
ADULT EXAMINATIONS
Tables 10 and 11 present the summary of analysisof data submitted for all nuclear medicine
examinations subject to DRL regulations.
They show, for the 2016-2018 period:











the number of assessments used,
the median weight for patients associatedwith the collected data,
the DRLs in force since 1 July 2019 (DRL),
the 50th percentile values for the datacollected,
the 75th to 25th percentile ratio,
the position of the 50th percentile withregard to the DRL in force since 1 July 2019(% DRL),the percentage of dose assessments
received for the period over the DRL inforce since 1 July 2019 (> DRL)
and the 50th percentile variation for theperiod with regard to the 2015 value
published in the previous report.

Detailed results for each examination type for
2016-2018 are shown in the report Annex.
It should be noted that for dynamic renal scanswith DTPA and brain perfusion SPECT scans with
ECD, the position of the median with regard to the
DRL in force since 2019 cannot be used because
there is insufficient data.
For other examinations, except for the thyroid scanwith 99mTc and the tumour FDG PET scan, analysis
for the 2016-2018 period shows that median valuesof the administered activities and administeredactivities per body weight are comparable to the
DRL in force (differences of between -7 and +2%)
and are relatively stable compared with theprevious report.
For the FDG-PET scan, administered activities andactivities per body weight are below the DRLs inforce by 13 and 14% respectively. This could be due
to technological developments such as increasinguse of the time of flight (TOF) technique identified
in the previous report (8), and departments'
commitment to optimising doses delivered topatients.
For thyroid scans with 99mTc, the median value ofadministered activities is 17% below the DRL inforce. This is primarily due to the fact that the DRL
in force was increased in ASN resolution 2019-DC0667 compared with the value in force for the
2016-2018 period. The median value is 16% down on
the 2015 value. This shows that although the DRLs
set in 2004 and 2011 were lower than actual values
used in practice, there was room for optimisation.
For this examination, Figure 85 (see Annex)
presents the results of the median values ofadministered activities by assessment and shows
two very clear peaks at 80 and 110 MBq. Thisillustrates the fact that some departments use themaximum values recommended by the marketing
authorisation (80 MBq maximum), while others use
SFMN recommendations (39) (maximum value 110
MBq).
For lung perfusion, the distribution of medianadministered activities by assessment (Figure 81 in
the Annex) presents peaks that correspond toactivities that are multiples of 37 MBq: 111, 148,
185 and 222 MBq. It therefore seems that many
professionals choose whole multiples of millicuries(mCi) for administered activities. Lung scans may
include two phases: a ventilation scan using either
technetium aerosols or krypton 81m and the lungperfusion scan. They can include either or boththese two phases, and the ventilation scan
generally precedes lung perfusion. If 99mTc(aerosols) is used for the ventilation examination,
the activity of 99mTc (albumin macroaggregate)
administered for the perfusion scan needs to besignificantly higher in order to mask the ventilation
signal (count rate 4 times higher than for
ventilation, according to SFMN recommendations(40)). This is not the case when the ventilation
examination takes place in advance, or when it isperformed using krypton 81m. It would beinteresting to carry out a specific study to separateout protocols with and without a prior 99mTc
ventilation examination, which are currently
combined in the data received.
Similarly for PET scans, there are peaks in 0.5
MBq/kg steps at 2.5, 3 and 3.5 MBq/kg (Figure112). And for bone scans (Figure 78), results show 2
clear peaks at 9 and 10 MBq/kg. This illustrates thediffering practices of departments, which can be
explainedbythedifferenceindevices
performance.

51

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT
Table 10: Summary of results of analysis of nuclear medicine data by adult examination type, for 2016-2018 data, interms of administered activity.

Examination typeRadiopharmaceutical / protocol

N

Medianweight(kg)

Administered activity
(MBq)
DRL

P50

P75/P25
ratio

% DRL

> DRL

Variation

Bone scan

99m

Tc HDP/DPD

203

72.0

670

662

1.13

-1%

42%

-1%

Lung perfusion scan

99m

Tc MAA

130

73.0

225

209

1.36

-7%

45%

-6%

123

Thyroid scan

I (sodium iodide)99m

Tc (sodium pertechnetate)
1 day/1st inj.

1.41

-3%

47%

+1%

91

1.45

-17%

37%

-16%

121

78.0

285

279

1.20

-2%

43%

-2%

78.0

785

769

1.21

-2%

41%

-2%

19

81.5

615

625

1.56

+2%

53%

+2%

2 days/2nd inj.

18

81.8

615

597

1.66

-3%

50%

-2%

1 injection

26

78.8

110

107

1.51

-3%

38%

-2%

Reinjection

21

79.0

37

37

1.59

+0%

43%

+1%

Tc human serum albumin/red
blood cells

57

71.0

740

737

1.25

-0%

47%

-0%

99m

Tc MAG3

80

68.0

180

181

1.64

+0%

53%

+2%

99m

Tl
(thallium chloride)

Tumour FDG PET

7.8

118

201

Brain perfusion SPECT

8
110

inj.

Tc
Myocardial perfusion
MIBI/tetrofosmin
SPECT with stress test
(dynamical or
pharmacological)

Dynamic renal scan

70.0
69.0

2 days/1st inj.

99m

Equilibrium
radionuclide
ventriculography

nd

49
112

1 day/2

st99m

Tc DTPA

8

68.5

255

248

1.68

-3%

25%

-2%

99m

Tc ECD

3

70.0

800

712

1.07

-11%

0%

-12%

99m

Tc HMPAO

25

70.0

695

662

1.48

-5%

44%

-4%

F FDG

150

70.0

245

212

1.33

-13%

26%

-12%

18

Table 11: Summary of results of analysis of nuclear medicine data by adult examination type, for 2016-2018 data, interms of administered activity per body weight.

Examination type

Bone scanRadiopharmaceutical / protocol

99m

Tc HDP/DPD
stMyocardial perfusion
SPECT with stress test
(dynamical or
pharmacological)

Tc
MIBI/tetrofosminTl(thallium chloride)
Tumour FDG PET

52

18

F FDG

DRL

P50

203

72.0

9.5

P75/P25
ratio

% DRL

> DRL

Variation

9.2

1.17

-3%

38%

-0%

121

78.0

3.7

3.6

1.23

-2%

38%

-1%

118

78.0

10.3

10.0

1.20

-3%

40%

-3%

2 days/1 inj.

19

81.5

7.7

7.4

1.47

-4%

42%

-4%

1 day/2

nd
st

nd

18

81.8

7.7

7.5

1.39

-3%

44%

-2%

1 injection

26

78.8

1.4

1.36

1.50

-3%

35%

-1%

Reinjection

21

79.0

0.5

0.48

1.52

-4%

14%

+2%

150

70.0

3.5

3.0

1.35

-14%

25%

-14%

2 days/2
201

Activity per BW(MBq/kg)inj.

1 day/1 inj.
99m

Medianweight
(kg)

N

inj.

st

NUCLEAR MEDICINEPAEDIATRIC EXAMINATIONSThere were dose assessments for 10 examination
types (taking into account weight categories). Noneof them represent more than 10 assessments
submitted. It is therefore not possible to performstatistical analyses. The results are shown in Table
12, but are not discussed.
The quantity of data received remains too low toprovide a clear overview of practices and update
current DRLs, which are based on European
AssociationofNuclear
Medicine(EANM)
recommendations from 2007.
In order to remedy this situation revealed in theprevious report, a survey (26), presented in thepaediatrics focus section, of all nuclear medicine
departments was carried out by the SFMN, theSFPM and IRSN targeting the most common
paediatric examinations (bone, renal and PET
scans) in late 2016 and early 2017. Around 80 sites
replied. The results showed that medianadministered activities in France were roughly at
the DRL level in force. FDG administered activities
were, like the DRLs, over 40% lower than the EANM

recommendations for oncology PET scans.
However, for DMSA renal scans, not covered by the
DRLs until now, the administered activities inFranceweresignificantly
overEuropeanrecommendations.
Given the low differences, the DRLs in force foradministered activities did not need to be updated
in ASN resolution 2019-DC-0667. However, thesurvey confirmed the need for a DRL for renal
cortical scans, and this was added to the list of
paediatric examinations in the ASN resolution
published in 2019. The DRL value for thisexamination corresponds to the European
recommendations
in
order
to
encourage
departments to optimise.
Finally, the survey showed a general homogeneity
in practices at national level. However, theactivities administered by some centres presented
significant differences from the majority ofcentres. Implementing DRLs should make it possible
to limit these unusual practices.

Table 12: Summary of results of analysis of child nuclear medicine data, by examination type.

Examination type

Rein dynamique MAG3

Squelette

TEP FDG

Thyroïde 123IClasse depoids (kg)

N

10 kg

6

20 kg

Medianweight (kg)

Administered activity (MBq)e

P75/P25
ratio

> DRL

NRD

50

9.5

25

22

1.15

0%

1

19.5

35

30

1.00

0%

10 kg

4

11.0

95

119

1.29

100%

20 kg

3

19.0

170

162

1.12

33%

30 kg

2

29.0

240

231

1.01

0%

40 kg

1

40.0

310

290

1.00

0%

20 kg

3

19.0

70

77

1.26

67%

30 kg

2

29.8

100

101

1.03

100%

40 kg

3

39.0

125

129

1.02

100%

3.5 kg

1

3.7

-

1.2

1.00

0%

53

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

FOCUS
Influence of CZT technology on administered activities
for myocardial perfusion SPECT
Detector technology with CZT (cadmium-zinc-telluride) semi-conductors started to be used in nuclear
medicine around fifteen years ago, and improves the detection performance and resolution of imaging
devices. Cardiac-centered cameras were the first CZT nuclear medicine imaging devices. Their specificgeometry made it possible to improve detection performance by hugging the shape of the patient’s chest,
and limit the size of CZT detectors, which are much more expensive than conventional detectors. Largefield CZT cameras then came in fitted with planar CZT detectors, and more recently multiple mobile CZT
detectors (radial and swivel motion). According to the ASN data published following a survey of nuclear
medicine professionals, around 10% of cameras were fitted with CZT detectors in 2017 (38).
Figure 28 and Table 13 show the impact of camera type on administered activities during myocardial
perfusion scans with 99mTc. Figure 28 shows the distributions, by camera type, of the median values of thetotal activities per body weight administered to patients (combination of both injections under stress andat rest) for the 2016-2018 period as a function of camera type, showing cardiac-centered CZT cameras andconventional scintillation cameras (Anger type). No dose assessment was received for a large-field CZTcamera. The camera model used was identified for 92% of data received via an email survey ofprofessionals, since this information is rarely included in data received.

Figure 28: Distribution by camera type of median total activities per body weight administered for myocardial
perfusion SPECT scans with 99mTc (protocol with 2 injections on 1 day). Only data for cameras whose type could be
identified and that include the activities for both injections were included.

54

NUCLEAR MEDICINE

Table 13 shows a difference between the two types of camera: the 50th percentile of the total
administered activity per body weight for caradiac-centered CZT cameras is about 2.5 MBq/kg lower thanthose of conventional cameras. However, there are disparities between users of the same type of camera.
For conventional cameras, the total administered activity per body weight is close to SFMN
recommendations (14.7 MBq/kg for the 2 injections combined) and the DRLs (14 MBq/kg for the 2
injections combined) in a large majority of units (around 80% are between 12 and 15 MBq/kg); however,lower, and especially higher, values are observed. For around 70% of CZT cameras, the administeredactivity per body weight is within the range of the EANM recommendations (10 to 14 MBq/kg) published in2019 (38), with a peak around 10 MBq/kg. Practices seem a little less homogeneous with these more
recent devices than with conventional cameras. This can be explained by the lack of official
recommendations when the data was collected, and the unit’s recent arrival in some institutions, which
probably means that it had not yet been used to its full potential. Finally, whatever system is used, as forall scintigraphy scans, the administered activity and examination duration are linked, and the balance
between these two parameters differs between institutions.

Table 13: Statistical data, by camera type, associated with the distribution of median total activities per bodyweight administered for myocardial perfusion SPECT scans with 99mTc (protocol with 2 injections on 1 jour). Only
data for cameras whose type could be identified and that include the activities for both injections were included.

Examination type

Myocarde avecépreuve d’effort et/ou
stimulation
pharmacologiqueRadiopharmaceutical
protocol99m

Tc
MIBI/tetrofosmin
1 day - 2 injections

Camera type

Total activity per BW (MBq/kg)(sum of the 2 injections)

N
Min

P50

Max

P75/P25

conventionnal
scintillation camera

81

9.3

13.9

20.2

1.14

cardiac-centered CZTcamera

27

6.0

11.3

18.7

1.27

55

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTSUMMARY
Analysis of nuclear medicine dose assessments shows:
●
●
●

●

●
●

a participation rate for nuclear medicine departments that has been stable at around 90% since 2014;a distribution of examinations selected by professionals for dose assessments that is consistent withthe frequency of nuclear medicine procedures in France;
general stability of administered median activities, except for downward trends for thyroid scanningwith 99mTc and tumour FDG PET (average of all examinations, decrease of around 3% since theprevious report);
administered median activities generally close to the DRLs in force since 1 July 2019 except forthyroid scanning with 99mTc and tumour FDG PET, for which median activities are significantly below
the DRLs in force;
results illustrating disparities in practice of the various nuclear medicine departments;
a major lack of data in paediatrics;

RECOMMENDATIONS
Analysis of nuclear medicine dose assessments leads IRSN to make the following recommendations:●●56

perform a specific lung perfusion scan study to distinguish between examinations performed with orwithout 99mTc ventilation;
for paediatrics: monitor and assess the effectiveness of measures taken to remedy the current lack ofdata.

DRLs: PERSPECTIVES,SUMMARY AND
RECOMMENDATIONSCONTENTSPERSPECTIVESSUMMARY AND RECOMMENDATIONSANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTThe first goal in analysing DRL data is to provide information to the authorities with a view toperiodically updating the DRLs and, more broadly, understand implementation of the optimisation
approach and the state of practice, from a dosimetry perspective, on a national level.
Since 2004, the implementation of DRLs in France
has been contributing to significantly improving
understanding of patient exposure in medical
imaging.
In general, DRLs help professionals consider theirpractice from a dosimetry perspective. Nationallevel data collection and analysis makes it possible
to assess:
implementationofprofessional
recommendations;● the impact on doses of replacing imaging
equipment with new technologies on a national
level.
With regard to national assessment of practices,from a dosimetry perspective, the current datacollection and analysis system seems to be
operating well. There is a significant volume ofdata. The conventional radiology participation rateis, however, disappointingly low (only 50% of
institutions). Apart from the special case of
paediatrics, the report could be considered
representative of the situation in France withsatisfactory representation of the various types of
medical imaging institutions (public, privatecommercial or non-profit).

and the consistency of protocols from a dosimetry
perspective.
The main sources of dose optimisation weaknesses
that the collection and analysis of DRL data made it
possible to identify in departments are:●●●With regard to the assessment of practice atinstitution level, IRSN’s exchanges with its contacts
in imaging institutions have regularly given it theopportunity to understand the value of DRLs as an
information and alert tool on imaging performance,

58●

protocols that are unsuitable for the type of
patient examined (adult/child);abnormaltechnical
parameter
values:automatic exposure, high voltage (kV), current(mAs), etc.;
equipment malfunctions: automatic exposure
control, detector.

Some institutions repeat dose assessments for thesame examination type within a short period oftime (weeks/months). This may be due to theidentification of a sub-optimal practice during thefirst assessment. The second assessment a shortwhile afterwards can be used to measure theeffectiveness of actions implemented.
It should be noted that a study on the change in
exposures for institutions performing two dose
assessments for the same type of examination forthe same unit, at a two-year interval, in 2013 and2015, was carried out in the previous report (8).
This study showed that doses were almost always
lower on the second assessment. This demonstrates
the effectiveness of the DRL system for
optimisation when it is implemented in institutions.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTPERSPECTIVESDRLs have now been implemented in France formore than fifteen years. Some problems have been
dealt with and others should be in the near future
thanks to application of ASN resolution 2019-DC0667. There is, however, room for some additional
improvements.
Analysis of data collected over the 2016-2018
period shows a decrease in DRL quantities in allareas, which could offer justification for changing
regulations. The vast majority of results are below
the new DRLs in force since 1 July 2019. This canbe explained by two reasons whose influences
cannot be separated: technological developmentson the one hand, and the optimisation of protocols
and awareness of good practices among users on
the other. However, deviations from these DRLs arequite small, and there is no need to revise the DRL
values in the near future. Moreover, more time isneeded for experience feedback on the applicationof DRLs introduced on 1 July 2019 for new
examinations,especiallyininterventional
radiology.
IRSN proposals therefore focus primarily on adding
new examination types or improving collection
methods.

Changes to list of examinations
Mammography and breast tomosynthesis
For mammography, the dose assessments submitted
are determined for an equivalent breast thicknessof 45 mm during annual external quality control of
medical devices as defined by ANSM. The values
submitted are therefore not representative of theclinical practice of sites. Moreover, ANSM average
glandular dose (AGD) measurement methods haverecently changed, and now require the use of
Polyethylene (PE) plates with the PMMA plates, so
the 45 mm equivalent breast thickness no longer
applies. They will enter into force from 22 January
2021 (35). It therefore seems necessary to revise

the DRL for mammography. Furthermore, IRSN
recommends adding breast tomosynthesis to thelist of examinations covered by the DRL system. A
survey could be performed to determine whether it
would be possible to implement DRLs for
mammography and breast tomosynthesis that are
representative of clinical practice on sites.
Cone-beam computed tomography (CBCT)
Similarly, a survey on CBCT in dental radiology
could be useful, especially for paediatrics, given
the increasing use of this technique and the highdoses sometimes delivered.

Using clinical indications in computed tomography
As illustrated with the chest CT scan in this report,
defining DRLs by anatomical region for computed
tomography leads to combining data that is very
heterogeneous, because they present significantly
varying clinical objectives. An SFPM working group
recently studied doses delivered for different
clinical indications in computed tomography anddiscovered significant differences depending on
indications for some anatomical regions (skull,chest,
abdomen-pelvis)(22).
Computed
tomography DRLs could be updated to take this into
account. This is also being worked on at a European
level with the EUCLID (23) project that IRSN is
associated with.

Introduction of diagnostic performance assessment into the DRL process
Finally, as mentioned in the previous report,
diagnostic performance assessment should be
associated with the patient dose optimisation
system in order to ensure that it does not impair
examination quality. In particular, if local median59

values are lower than the regulatory achievable
doses values recently introduced in the regulations,image quality, rather than dose, should beconsidered as a priority in the optimisation process.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTSUMMARY and RECOMMENDATIONS
Analysis of the data collected for the 2016-2018 period, and more generally of DRL implementation
since 2004, leads to the following observations:
●
●
●
●
●
●

the DRL data collection and analysis system works well from the perspective of understanding
practices and updating existing DRLs, except in paediatrics;
there is a major lack of data in paediatrics;
downward trends for DRL quantities justifies regularly reviewing regulations;for mammography, the DRL is not representative of clinical practice on sites. Regardless, it will nolonger be able to be used from 22 January 2021 due to the updated quality control decision;
defining computed tomography DRLs by anatomical region limits their applicability;
the current DRL system does not prevent patient dose optimisation from impairing examination image
quality.

Consequently, IRSN makes the following recommendations:
●
●
●
●
●

60

the system for reviewing technical aspects of the regulations needs to be made more flexible so thatit can respond better to changes in practices and technologies;
some areas need to be reviewed: modification of DRL for mammography, addition of breast
tomosynthesis and CBCT for dental radiology;plans need to be made for computed tomography DRLs to be defined by clinical indication;
diagnostic performance of equipment needs to be associated with the dose optimisation approach;the effectiveness of measures taken recently to remedy the current lack of paediatric data needs tobe assessed.

DRLS:PERSPECTIVES, SUMMARY AND
RECOMMENDATIONSCONCLUSIONSThis sixth analysis report on French diagnostic
reference level data comes against the backdrop of
new regulations that came into force on 1 July
2019. Among other things, they take into account
IRSN’s recommendations in previous reports. Theyalign with the recent changes in international
recommendations, in accordance with thereinforced DRL requirements set out in Council
Directive 2013/59/Euratom (16). This is therefore atransitionary report.
The results of this report confirm that theseregulatory updates covering both organisational
and technical aspects were justified. The nextreport should show how effective these adaptations
have been, especially regarding the collection of
paediatric data.
Analysis of data collected over the 2016-2018
period also shows a decrease in DRL quantities inall areas, which could offer justification forchanging regulations. The vast majority of results

are below the new DRLs in force since 1 July 2019.
However, deviations from these new DRLs are quite
small.
These results suggest that it would not beworthwhile recommending updates in the DRLs
defined in ASN resolution2019-DC-0667 in the near
future.
Moreover, IRSN recommends reviewing the digital
mammography DRL in order to make it more
relevant to clinical practice. IRSN also recommends
adding breast tomosynthesis and CBCT in dental
radiology to the list of examinations.
Furthermore, plans need to be made for computed
tomography DRLs to be defined by clinicalindication in the light of recent studies on thesubject (22; 23).
Finally, work needs to be done on associating
device diagnostic performance assessment withdose optimisation.

61

GLOSSARY
Abbreviations
AD

Achievable dose

AGD

Average glandular dose

ANSM

Agence nationale de sécurité du médicament et des produits de santé(French National Agency for Medicines and Health Products Safety (ANSM))

AP

Anterior posterior

ASN

Autorité de sûreté nucléaire
(French Nuclear Safety Authority)

BMI

Body mass index

BW

Body weight

CBCT

Cone-beam computed tomography

CPD

Continuing professional development

CTDIvol

Volume computed tomography dose index

DAP

Dose area product

DGOS

Direction générale de l’offre de soins (Directorate General for Healthcare
Services)

DLP

Dose length product

DRL

Diagnostic reference level

DTPA

Diethylene triamine pentaacetic acid

EANM

European Association of Nuclear Medicine

EC

European Commission

ECD

Ethyl cysteine dimer

ESD

Entrance surface dose

FDD

Focus-to-detector distance

FDG

Fluorodeoxyglucose

FNMR

Fédération Nationale des Médecins Radiologues (French National Federation ofRadiologists)

FSD

Focus-to-skin distance

GPMED

Groupe permanent d'experts pour le domaine des expositions médicales etmédico-légales des rayonnements ionisants (Advisory committee for medical
exposure)

HAS

Haute autorité de santé(French national health authority)

HMPAO

Hexa-methyl propylene amine oxime

IAEA

International Atomic Energy Agency

ICRP

International Commission on Radiological Protection

IRSN

Institut de radioprotection et de sûreté nucléaire
(French institute for radiation protection and nuclear safety)

LVEF

Left ventricular ejection fraction

OPT

Orthopantomography

62

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTPA

Posterior anterior

PET

Positron emission tomography

SFIPP

Société Francophone d'Imagerie Pédiatrique et Prenatale(French-speaking Society for Paediatric and Prenatal Imaging)

SFMN

Société française de médecine nucléaire et imagerie moléculaire(French Society of Nuclear Medicine)

SFPM

Société Française de Physique Médicale(French Society of Medical Physics)

SFR

Société Française de Radiologie(French Society of Radiology)

63

ANNEXESTYPE OF DATA TO BE REPORTED TO IRSNDETAILED ANALYSES BY FIELD AND TYPE OF EXAMINATION

64

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTTYPE OF DATA TO BE REPORTED TO IRSN

The type of data to be reported to IRSN varies depending on the field. In general, records must be kept forpatient groups. For mammography and orthopantomography, the data to be submitted are taken fromexternal quality control reports.

Table 14: List of data to be reported, according to field (excluding mammography and orthopantomography).
Field

General data

Data to be recorded for each patient

Conventional radiology

Year
Unit
Examination
Added filter
Focus-to-detector distance (cm)Detector size (cm x cm)

Patient age (year) [optional]
Patient weight (kg)Patient height (cm)High voltage (kV)Current-time product (mAs) [optional]
Focus-to-skin distance (cm) [optional]
DAP (mGy.cm² ; cGy.cm² ; dGy.cm² ; Gy.cm²
or µGy.m²)

Computed tomography

Year
Unit
Examination
Iterative reconstruction
algorithm use (Y/N)

Patient age (year) [optional]
Patient weight (kg)Patient height (cm)High voltage (kV)
Pitch [or increment + collimation]
CTDIvol (mGy)
DLP (mGy.cm)

Nuclear medicine

Year
Unit
Examination (cardiology
protocol)Radiopharamceutical

Patient weight (kg)Patient height (cm)Administered activity(ies) (MBq)

Table 15: List of data to be reported for mammographies and orthopantomographies.
Field
Digital mammography

Orthopantomography

General data
Year
Unit
Quality control date
Quality control report

Data to be collected from the external
quality control reportHigh voltage (kV)Current-time product (mAs)
Anode/filter combination
Half-value layer (mm AI)
Focus-to-phantom distance (cm)
Air KERMA (mGy)
Average glandular dose (mGy)High voltage (kV)DAP (mGy.cm2)

65

DETAILED ANALYSES BY FIELD AND TYPE OF EXAMINATIONThe statistical analyses of the results of dose assessments performed for 2016-2018 are given below foreach type of examination, in the form of datasheets.

Content
The datasheets include:●●

an initial section on the analysis of 2016-2018 data consisting of:- graphs showing the national distribution of reference doses (DAP in conventional radiology andin orthopantomography, AGD in mammography, CTDIvol and DLP in computed tomography,
administered activity and activity per body weight in nuclear medicine);- tables summarising the statistical measures on these values;
a second section on the change since 2011 of statistical measures in the 75th and 50th percentiles,
which serve as the basis for updating DRLs and ADs.

Analysis of 2016-2018 data
The data analysed are the median values per dose assessment (i.e. per unit) of the various reference dosevalues.
For example, the 75th percentile of the DAP is rigorously the “75th percentile of the distribution of dose
assessment median DAPs”. Similarly, the minimum and maximum DAP values are the minimum andmaximum values of the assessment median DAPs, and not the minimum or maximum DAP values for anindividual patient.

Graph key
●
●
●
●
●

N: number of dose assessments used for the analysis;
P75 (period): 75th percentile of the distribution of median values;
P50 (period): 50th percentile of the distribution of median values;
DRL (2019): diagnostic reference level (in force, as per ASN resolution 2019-DC-667);
AD (2019): achievable dose (in force, as per ASN resolution 2019-DC-667).

The period selected was either 2016-2018, or 2018 alone when the volume of data received allowed foryearly analysis (DAP in conventional radiology, CTDIvol and DLP in computed tomography).

Clarifications regarding the tables
Number of units above the DRL:●●

66

2011 DRL (in force when data was collected): mean value of the dose above the 2011 DRL;
2019 DRL (in force since 1 July 2019) median value of the dose above the 2019 DRL;ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

Change since 2011
Graphs show the change in statistical measures (75th and 50th percentiles) calculated based on the medianvalues of doses per unit since 2011. Since all the values published in the two previous reports (2011-2012
and 2013-2015) were based on means per unit, new values, based on medians per unit were calculatedusing patient doses. This calculation was not performed for data from 2004 to 2010, as only the means perunit were available in digital format.
To enable comparison between examinations despite higher diverging DRL orders of magnitude, a scale (tothe nearest rounded figure for easier reading) common to each field was defined for the coordinate axis
(dose value):●●●radiography: range of 0.8 DRL (for example, for chest PA radiographs, the DRL of the DAP is
200 mGy.cm² and the ordinates axis therefore covers a range of 160 mGy.cm², from 100 to 260
mGy.cm²), except for thoracic spine lateral radiographs, with a range of 1 DRL.
computed tomography: range of 0.8 DRL;
nuclear medicine: range of 0.6 DRL.

67

ADULT CONVENTIONAL RADIOLOGYFRONTAL CHEST
CHEST
(PA)
PA

Analysis of 2016-2018 data

Figure 29: Distribution of unit median DAP from dose assessments performed for adult posterior anterior chest
radiographs.

Table 16: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult posterior anterior chest radiographs.

Chest posterior anterior (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

250 (i.e. 25 cGy.cm²)

DRL in force (2019 DRL)

200

AD in force (2019 AD)

150

PeriodNumber of units

2016 - 2018

2018

1719

565
DAP (mGy.cm 2)

DRL quantity
75th percentile

187

50th percentile

130

118

Minimum – maximum values

16 - 673

16 - 544

Number of units above the 2011 DRL

176 (10%)57 (10%)

Number of units above the 2019 DRL

337 (20%)112 (20%)68

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ADULT CONVENTIONAL RADIOLOGYCHEST PA

Change since 2011

Figure 30: Change in the 75th and 50th percentiles of DAP for adult posterior anterior chest radiographs.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT69

ADULT CONVENTIONAL RADIOLOGYCHEST LAT

Analysis of 2016-2018 data

Figure 31: Distribution of unit median DAP from dose assessments performed for adult lateral chest radiographs.

Table 17: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult lateral chest radiographs.

Chest lateral (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

1000 (i.e. 100 cGy.cm²)

DRL in force (2019 DRL)

550

AD in force (2019 AD)

400

PeriodNumber of units

2016 - 2018

2018

684

234
DAP (mGy.cm 2)

DRL quantityth

75 percentile

525

489

50th percentile

387

369

Minimum – maximum values

54 – 1600

54 – 1115

Number of units above the 2011 DRL

14 (2%)

3 (1%)

Number of units above the 2019 DRL

155 (23%)44 (19%)70

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGYCHEST LAT

Change since 2011

Figure 32: Change in the 75th and 50th percentiles of DAP for adult lateral chest radiographs.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT71

ADULT CONVENTIONAL RADIOLOGYABDOMEN AP

Analysis of 2016-2018 data

Figure 33: Distribution of unit median DAP from dose assessments performed for adult anterior posterior abdomen
radiographs.

Tableau 18: Statistical data associated with the distribution of unit median DAP from dose assessments performed
for adult anterior posterior abdomen radiographs.

Abdomen anterior posterior (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

7000 (i.e. 700 cGy.cm²)

DRL in force (2019 DRL)

3400

AD in force (2019 AD)

2300

PeriodNumber of units

2016 - 2018

2018

410

128
DAP (mGy.cm 2)

DRL quantity
75th percentile3244

50th percentile

2233

2118

285 – 9030

285 – 6740

Minimum – maximum values

3104

Number of units above the 2011 DRL

4 (1%)

1 (1%)

Number of units above the 2019 DRL

91 (22%)23 (18%)72

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGYABDOMEN AP

Change since 2011

Figure 34: Change in the 75th and 50th percentiles of DAP for adult anterior posterior abdomen radiographs.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT73

ADULT CONVENTIONAL RADIOLOGYPELVIS AP

Analysis of 2016-2018 data

Figure 35: Distribution of unit median DAP from dose assessments performed for adult anterior posterior pelvis
radiographs.

Table 19: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult anterior posterior pelvis radiographs.

Pelvis anterior posterior (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

7000 (i.e. 700 cGy.cm²)

DRL in force (2019 DRL)

3800

AD in force (2019 AD)

2750

PeriodNumber of units

2016 - 2018

2018

1521

497
DAP (mGy.cm 2)

DRL quantity
75th percentile

3530

50th percentile

2470

2340

322 – 12184

421 – 10070

Minimum – maximum values

3437

Number of units above the 2011 DRL

30 (2%)

10 (2%)

Number of units above the 2019 DRL

311 (20%)97 (20%)74

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGYPELVIS AP

Change since 2011

Figure 36: Change in the 75th and 50th percentiles of DAP for adult anterior posterior pelvis radiographs.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

75

ADULT CONVENTIONAL RADIOLOGYHIP AP/LAT

Analysis of 2016-2018 data

Figure 37: Distribution of unit median DAP from dose assessments performed for adult anterior posterior or lateral
hip radiographs.

Table 20: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult anterior posterior or lateral hip radiographs.

Hip anterior posterior or lateral (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

3000 (i.e. 300 cGy.cm²)

DRL in force (2019 DRL)

1350

AD in force (2019 AD)

950

PeriodNumber of units

2016 - 2018

2018

593

217
DAP (mGy.cm 2)

DRL quantity
75th percentile1360

50th percentile

862

760

140 – 4432

156 – 4100

Minimum – maximum values

1186

Number of units above the 2011 DRL

16 (3%)

7 (3%)

Number of units above the 2019 DRL

152 (26%)

49 (23%)76

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGYHIP AP/LAT

Change since 2011

Figure 38: Change in the 75th and 50th percentiles of DAP for adult anterior posterior or lateral hip radiographs.
Anterior posterior or lateral hip radiographs were added to the list of examinations subject to DRLs by the Order of
24 October 2011. Therefore, data for this type of examination only started being collected in 2012.

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77

ADULT CONVENTIONAL RADIOLOGYCERVICAL SPINE AP/LAT

Analysis of 2016-2018 data

Figure 39: Distribution of unit median DAP from dose assessments performed for adult anterior posterior or lateralcervical spine radiographs.

Table 21: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult anterior posterior or lateral cervical spine radiographs.

Cervical spine anterior posterior or lateral (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

750 (i.e. 75 cGy.cm²)

DRL in force (2019 DRL)

400

AD in force (2019 AD)

250

PeriodNumber of units

2016 - 2018

2018

695

224
DAP (mGy.cm 2)

DRL quantity
75th percentile328

50th percentile

224

219

30 - 1220

30 - 763

Minimum – maximum values

325

Number of units above the 2011 DRL

8 (1%)

1 (0%)

Number of units above the 2019 DRL

118 (17%)35 (16%)78

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGYCERVICAL SPINE AP/LAT

Change since 2011

Figure 40: Change in the 75th and 50th percentiles of DAP for adult anterior posterior or lateral cervical spine
radiographs.
Anterior posterior or lateral cervical spine radiographs were added to the list of examinations subject to DRLs by theOrder of 24 October 2011. Therefore, data for this type of examination only started being collected in 2012.

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ADULT CONVENTIONAL RADIOLOGY

THORACIC SPINE AP

Analysis of 2016-2018 data

Figure 41: Distribution of unit median DAP from dose assessments performed for adult anterior posterior thoracic
spine radiographs.

Table 22: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult anterior posterior thoracic spine radiographs.

Thoracic spine anterior posterior (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

1750 (i.e. 175 cGy.cm²)

DRL in force (2019 DRL)

1000

AD in force (2019 AD)

750

PeriodNumber of units

2016 - 2018

2018

315

82
DAP (mGy.cm 2)

DRL quantity
75th percentile

97850th percentile

670

625

128 – 3505

280 – 2360

Minimum – maximum values

897

Number of units above the 2011 DRL

12 (4%)

2 (2%)

Number of units above the 2019 DRL

75 (24%)15 (18%)80

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGY

THORACIC SPINE AP

Change since 2011

Figure 42: Change in the 75th and 50th percentiles of DAP for adult anterior posterior thoracic spine radiographs.
Anterior posterior thoracic spine radiographs were added to the list of examinations subject to DRLs by the Order of
24 October 2011. Therefore, data for this type of examination only started being collected in 2012.

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ADULT CONVENTIONAL RADIOLOGY

THORACIC SPINE LAT

Analysis of 2016-2018 data

Figure 43: Distribution of unit median DAP from dose assessments performed for adult lateral thoracic spine
radiographs.

Table 23: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult lateral thoracic spine radiographs.

Thoracic spine lateral (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

2750 (i.e. 275 cGy.cm²)

DRL in force (2019 DRL)

1150

AD in force (2019 AD)

900

PeriodNumber of units

2016 - 2018

2018

129

30
DAP (mGy.cm 2)

DRL quantity
75th percentile1275

50th percentile

811

1021

104 – 3190

180 – 3190

Minimum – maximum values

1625

Number of units above the 2011 DRL

4 (3%)

1 (3%)

Number of units above the 2019 DRL

40 (31%)14 (47%)82

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THORACIC SPINE LAT

Change since 2011

Figure 44: Change in the 75th and 50th percentiles of DAP for adult lateral thoracic spine radiographs.
Lateral thoracic spine radiographs were added to the list of examinations subject to DRLs by the Order of 24 October
2011. Therefore, data for this type of examination only started being collected in 2012.

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ADULT CONVENTIONAL RADIOLOGYLUMBAR SPINE AP

Analysis of 2016-2018 data

Figure 45: Distribution of unit median DAP from dose assessments performed for adult anterior posterior lumbar
spine radiographs.

Table 24: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult anterior posterior lumbar spine radiographs.

Lumbar spine anterior posterior (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

4500 (i.e. 450 cGy.cm²)

DRL in force (2019 DRL)

2700

AD in force (2019 AD)

1950

PeriodNumber of units

2016 - 2018

2018

979

353
DAP (mGy.cm 2)

DRL quantity
75th percentile

2580

50th percentile

1770

1630

223 – 6597

223 – 5590

Minimum – maximum values

2405

Number of units above the 2011 DRL

18 (2%)

5 (1%)

Number of units above the 2019 DRL

209 (21%)64 (18%)84

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGYLUMBAR SPINE AP

Change since 2011

Figure 46: Change in the 75th and 50th percentiles of DAP for adult anterior posterior lumbar spine radiographs.

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85

ADULT CONVENTIONAL RADIOLOGYLUMBAR SPINE LAT

Analysis of 2016-2018 data

Figure 47: Distribution of unit median DAP from dose assessments performed for adult lateral lumbar spine
radiographs.

Table 25: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
adult lateral lumbar spine radiographs.

Lumbar spine lateral (adults)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

8000 (i.e. 800 cGy.cm²)

DRL in force (2019 DRL)

3900

AD in force (2019 AD)

2650

PeriodNumber of units

2016 - 2018

2018

580

201
DAP (mGy.cm 2)

DRL quantity
75th percentile3876

50th percentile

2699

2200

549 – 11820

702 – 11820

Minimum – maximum values

3540

Number of units above the 2011 DRL

6 (1.0%)3 (1.5%)

Number of units above the 2019 DRL

141 (24%)

38 (19%)86

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGYLUMBAR SPINE LAT

Change since 2011

Figure 48: Change in the 75th and 50th percentiles of DAP for adult lateral lumbar spine radiographs.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT87

ADULT CONVENTIONAL RADIOLOGYORTHOPANTOMOGRAPHY

Analysis of 2016-2018 data

Figure 49: Distribution of DAP from dose assessments performed for orthopantomography.

Table 26: Statistical data associated with the distribution of DAP from dose assessments performed fororthopantomography.

Orthopantomography
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

200 (i.e. 20 cGy.cm²)

DRL in force (2019 DRL)

150

AD in force (2019 AD)

100

Period2016 - 2018

Type of institution

All institutions

Dental practices

Other institutions

Number of units

371

114

257

DAP (mGy.cm 2)

DRL quantityth

75 percentile

129

th

50 percentile
Minimum – maximum values

117

134

97

87

102

7 - 239

28 - 188

7 - 239

Number of units above the 2011 DRL

3 (0.8%)03 (1.2%)

Number of units above the 2019 DRL

49 (13%)

11 (10%)38 (15%)88

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT CONVENTIONAL RADIOLOGYORTHOPANTOMOGRAPHY

Change since 2011

Figure 50: Change in the 75th and 50th percentiles of DAP for orthopantomography.

Orthopantomography was added to the list of examinations subject to DRLs by the Order of 24 October 2011.
Therefore, data for this type of examination only started being collected in 2012. The number of dose assessments
received in 2012 was considered insufficient for use.

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89

ADULT CONVENTIONAL RADIOLOGYMAMMOGRAPHY

Analysis of 2016-2018 data

Figure 51: Total distribution of AGD from dose assessments performed for digital mammography.

Figure 52: Distribution by type of detector of AGD from dose assessments performed for digital mammography.

90

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Table 27: Statistical data associated with total distributions of AGD from dose assessments performed for digital
mammography, by type of detector.

Digital mammography
DRL quantity
DRL in force during data collection(2011 DRL)DRL in force (2019 DRL)AGD (mGy)
1.8
1.6

AD in force (2019 AD)

1.3

Period2016 - 2018

Type of detector

All systems

Number of units

484

CR systems
Photostimulable
phosphor plate71

75th percentile

1.54

1.84

1.43

50th percentile

1.26

1.74

1.22

0.58

Minimum – maximum values

0.39 - 2.00

0.84 - 2.00

0.61 - 2.00

0.39 - 0.98

Number of units above the 2011 DRL

46 (10%)22 (31%)24 (6%)

0

Number of units above the 2019 DRL

94 (19%)46 (65%)48 (13%)0

DRL quantity

DR systems
Flat panel
Photon-counting
detectordetector
383
30

AGD (mGy)
0.70

Change since 2011

Figure 53: Change in the 75th and 50th percentiles of AGD for digital mammography.

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PAEDIATRIC CONVENTIONAL RADIOLOGYCHEST AP 10 kg

Analysis of 2016-2018 data

Figure 54: Distribution of unit median DAP from dose assessments performed for paediatric (10 kg) anterior posterior
chest radiographs.

Table 28: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
paediatric (10 kg) anterior posterior chest radiographs.

Chest anterior posterior (children 10 kg)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

20 (i.e. 2 cGy.cm²)

DRL in force (2019 DRL)-

AD in force (2019 AD)-

Period2016 - 2018

Number of units

43

DRL quantity

DAP (mGy.cm 2)75th percentile

19

50th percentile

13

Minimum – maximum values

2 - 51

Number of units above the 2011 DRL

10 (23%)

Number of units above the 2019 DRL-

Change since 2011
Due to the very low number of dose assessments received each year, it does not seem relevant to present a curve
where variations are more related to the statistical inconsistency of data than the change in delivered doses over
time.

92

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Analysis of 2016-2018 data

Figure 55: Distribution of unit median DAP from dose assessments performed for paediatric (20 kg) posterior anterior
chest radiographs.

Table 29: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
paediatric (20 kg) posterior anterior chest radiographs.

Chest posterior anterior (children 20 kg)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

50 (i.e. 5 cGy.cm²)

DRL in force (2019 DRL)-

AD in force (2019 AD)-

Period2016 - 2018

Number of units

22

DRL quantity

DAP (mGy.cm 2)75th percentile

43

50th percentile

28

Minimum – maximum values

11 - 115

Number of units above the 2011 DRL

3 (14%)

Number of units above the 2019 DRL-

Change since 2011
Due to the very low number of dose assessments received each year, it does not seem relevant to present a curve
where variations are more related to the statistical inconsistency of data than the change in delivered doses overtime.

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PAEDIATRIC CONVENTIONAL RADIOLOGYPELVIS AP 10 kg

Analysis of 2016-2018 data

Figure 56: Distribution of unit median DAP from dose assessments performed for paediatric (10 kg) anterior posterior
pelvis radiographs.

Table 30: Statistical data associated with the distribution of unit median DAP from dose assessments performed for
paediatric (10kg) anterior posterior pelvis radiographs.

Pelvis anterior posterior (children 10 kg)
DAP (mGy.cm 2)

DRL quantity
DRL in force during data collection (2011 DRL)

30 (i.e. 3 cGy.cm²)

DRL in force (2019 DRL)-

AD in force (2019 AD)-

Period2016 - 2018

Number of units

24

DRL quantity

DAP (mGy.cm 2)75th percentile

29

50th percentile

19

Minimum – maximum values

2 - 70

Number of units above the 2011 DRL

5 (21%)

Number of units above the 2019 DRL-

Change since 2011
Due to the very low number of dose assessments received each year, it does not seem relevant to present a curve
where variations are more related to the statistical inconsistency of data than the change in delivered doses over
time.

94

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BRAIN

Analysis of 2016-2018 data

Figure 57: Distribution of unit median CTDIvol from dose assessments performed for adult brain CTacquisitions.

Figure 58: Distribution of unit median DLP from dose assessments performed for adult brain CT acquisitions.

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95

ADULT COMPUTED TOMOGRAPHY

BRAIN

Table 31: Statistical data associated with the distribution of unit median CTDIvol and DLP from dose assessments
performed for adult brain CT acquisitions.

Brain CT (adults)
DRL quantity

CTDI vol (mGy)

DLP (mGy.cm)

DRL in force during data collection (2011 DRL)

65

1050

DRL in force (2019 DRL)

46

850

AD in force (2019 AD)

40

725

PeriodNumber of units

2016 - 201820182016 - 2018

2018

1284

422

1288

422

41.0

771

DRL quantity

CTDI vol (mGy)75th percentile

42.2

th

50 percentile

DLP (mGy.cm)
742

37.9

37.0

689

675

Minimum – maximum values

20.4 - 69.8

23.3 - 61.1

362 – 1261

413 – 1071

Number of units above the 2011 DRL

1 (0.1%)0

3 (0.2%)1 (0.2%)

Number of units above the 2019 DRL

185 (14%)48 (11%)154 (12%)44 (10%)Change since 2011

Figure 59: Change in the 75th and 50th percentiles of CTDIvol for adult brain CT acquisitions.

Figure 60: Change in the 75th and 50th percentiles of DLP for adult brain CT acquisitions.

96

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CHEST

Analysis of 2016-2018 data

Figure 61: Distribution of unit median CTDIvol from dose assessments performed for adult chest CT acquisitions.

Figure 62: Distribution of unit median DLP from dose assessments performed for adult chest CT acquisitions.

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ADULT COMPUTED TOMOGRAPHY

CHEST

Table 32: Statistical data associated with the distribution of unit median CTDIvol and DLP from dose assessments
performed for adult chest CT acquisitions.

Chest CT (adults)
DRL quantity

CTDI vol (mGy)

DLP (mGy.cm)

DRL in force during data collection (2011 DRL)

15

475

DRL in force (2019 DRL)

9.5

350

AD in force (2019 AD)

7.5

275

PeriodNumber of units

2016 - 201820182016 - 2018

2018

1007

337

1010

337

7.5

299

DRL quantity

CTDI vol (mGy)75th percentile

7.9

th

50 percentile

DLP (mGy.cm)
286

6.6

6.3

252

240

Minimum – maximum values

1.7 - 17.0

1.8 - 17.0

62 - 589

71 - 589

Number of units above the 2011 DRL

3 (0.3%)1 (0.3%)

11 (1.1%)

4 (1.2%)

Number of units above the 2019 DRL

99 (10%)19 (6%)

105 (10%)24 (7%)

Change since 2011

Figure 63: Change in the 75th and 50th percentiles of CTDIvol for adult chest CT acquisitions.

Figure 64: Change in the 75th and 50th percentiles of DLP for adult chest CT acquisitions.

98

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CHEST-ABDOMEN-PELVIS

Analysis of 2016-2018 data

Figure 65: Distribution of unit median CTDIvol from dose assessments performed for adult chest-abdomen-pelvis (CAP)CT acquisitions.

Figure 66: Distribution of unit median DLP from dose assessments performed for adult chest-abdomen-pelvis (CAP)CT acquisitions.

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99

ADULT COMPUTED TOMOGRAPHY

CHEST-ABDOMEN-PELVIS

Table 33: Statistical data associated with the distribution of unit median CTDIvol and DLP from dose assessments
performed for adult chest-abdomen-pelvis CT acquisitions.

Chest-abdomen-pelvis CT (adults)
DRL quantity

CTDI vol (mGy)

DLP (mGy.cm)

20

1000

DRL in force (2019 DRL)

11

750

AD in force (2019 AD)

9.5

650

DRL in force during data collection (2011 DRL)

PeriodNumber of units

2016 - 201820182016 - 2018

2018

591

207

592

207

10.1

711

DRL quantity

CTDI vol (mGy)75th percentile

10.3

th

50 percentile

DLP (mGy.cm)
689

8.9

8.5

613

598

Minimum – maximum values

3.4 - 21.0

3.5 - 20.7

223 – 1438

238 – 1416

Number of units above the 2011 DRL

1 (0.2%)1 (0.5%)22 (3.7%)

5 (2.4%)

Number of units above the 2019 DRL

108 (18%)32 (15%)109 (18%)30 (14%)

Change since 2011

Figure 67: Change in the 75th and 50th percentiles of CTDIvol for adult chest-abdomen-pelvis CT acquisitions.

Figure 68: Change in the 75th and 50th percentiles of DLP for adult chest-abdomen-pelvis CT acquisitions.

100

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT COMPUTED TOMOGRAPHYABDOMEN-PELVIS

Analysis of 2016-2018 data

Figure 69: Distribution of unit median CTDIvol from dose assessments performed for adult abdomen-pelvis CT
acquisitions.

Figure 70: Distribution of unit median DLP from dose assessments performed for adult abdomen-pelvis CT
acquisitions.

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ADULT COMPUTED TOMOGRAPHYABDOMEN-PELVIS

Table 34: Statistical data associated with the distribution of unit median CTDIvol and DLP from dose assessments
performed for adult abdomen-pelvis CT acquisitions.

Abdomen-pelvis CT (adults)
DRL quantity

CTDI vol (mGy)

DLP (mGy.cm)

DRL in force during data collection (2011 DRL)

17

800

DRL in force (2019 DRL)

13

625

AD in force (2019 AD)

11

525

PeriodNumber of units

2016 - 201820182016 - 2018

2018

963

354

966

354

10.1

524

DRL quantity

CTDI vol (mGy)75th percentile

10.5

th

50 percentile

DLP (mGy.cm)
492

9.2

8.9

450

430

Minimum – maximum values

3.2 - 18.5

3.2 - 18.3

157 - 967

157 - 845

Number of units above the 2011 DRL

5 (0.5%)1 (0.3%)8 (0.8%)1 (0.3%)

Number of units above the 2019 DRL

59 (6%)

11 (3%)

73 (8%)

13 (4%)

Change since 2011

Figure 71: Change in the 75th and 50th percentiles of CTDIvol for adult abdomen-pelvis CT acquisitions.

Figure 72: Change in the 75th and 50th percentiles of DLP for adult abdomen-pelvis CT acquisitions.

102

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LUMBAR SPINE

Analysis of 2016-2018 data

Figure 73: Distribution of unit median CTDIvol from dose assessments performed for adult lumbar spine CT
acquisitions.

Figure 74: Distribution of unit median DLP from dose assessments performed for adult lumbar spine CT acquisitions.

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ADULT COMPUTED TOMOGRAPHY

LUMBAR SPINE

Table 35: Statistical data associated with the distribution of unit median CTDIvol and DLP from dose assessments
performed for adult lumbar spine CT acquisitions.

Lumbar spine CT (adults)
DRL quantity

CTDI vol (mGy)

DLP (mGy.cm)

DRL in force during data collection (2011 DRL)

45

700

DRL in force (2019 DRL)

28

725

AD in force (2019 AD)

23

625

PeriodNumber of units

2016 - 201820182016 - 2018

2018

858

298

860

298

24.1

671

DRL quantity

CTDI vol (mGy)75th percentile

24.9

th

50 percentile

DLP (mGy.cm)
654

21.1

20.7

573

564

9.8 - 48.1

10.9 - 48.1

256 – 1236

256 – 1202

Number of units above the 2011 DRL

00

226 (26%)

64 (22%)

Number of units above the 2019 DRL

103 (12%)27 (9%)

141 (16%)40 (13%)

Minimum – maximum values

Change since 2011

Figure 75: Change in the 75th and 50th percentiles of CTDIvol for adult lumbar spine CT acquisitions.

Figure 76: Change in the 75th and 50th percentiles of DLP for adult lumbar spine CT acquisitions.
Lumbar spine CT scans were added to the list of examinations subject to DRLs by the Order of 24 October 2011.
Therefore, data for this type of examination only started being collected in 2012.

104

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ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 77: Distribution of unit median administered activities from dose assessments performed for adult bone scans.

Figure 78: Distribution of unit median administered activities per body weight from dose assessments performed for
adult bone scans.

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BONE SCAN (99mTc)

ADULT NUCLEAR MEDICINE

Table 36: Statistical data associated with the distribution of unit median administered activities from dose
assessments performed for adult bone scans.

Bone scan (adults)
99m

Radiopharmaceutical(s)DRL quantity
DRL in force during data collection (2011 DRL)DRL in force (2019 DRL)

Administered activity
(MBq)
700

Tc-HDP, 99mTc-DPD
Administered activity per body weight(MBq/kg)-

670

Period9.5
2016 – 2018

Number of units

203

203

Administered activity
(MBq)
662

Administered activity per body weight(MBq/kg)
9.2

Minimum – maximum values

469 - 808

6.3 – 11.2

Number of units above the 2011 DRL

49 (24%)-

Number of units above the 2019 DRL

85 (42%)78 (38%)

DRL quantity
50th percentile

Change since 2011

Figure 79: Change in the 50th percentile of administered activity for adult bone scans.

Figure 80: Change in the 50th percentile of administered activity per body weight for adult bone scans.

106

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ADULT NUCLEAR MEDICINEADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 81: Distribution of unit median administered activities from dose assessments performed for adult perfusion
lung scans.

Table 37: Statistical data associated with the distribution of unit median administered activities from dose
assessments performed for adult perfusion lung scans.

Lung perfusion scan (adults)
99m

Radiopharmaceutical(s)DRL quantity

Tc-macroaggregated human albumin, 99mTc-microspheres
Administered activity (MBq)

DRL in force during data collection (2011 DRL)240

DRL in force (2019 DRL)

225

Period2016 - 2018
130

Number of units
DRL quantity

Administered activity (MBq)50th percentile

209

Minimum – maximum values

107 - 404

Number of units above the 2011 DRL

38 (29%)Number of units above the 2019 DRL

59 (45%)ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT107

ADULT NUCLEAR MEDICINEPERFUSION LUNG SCAN (99mTc)

Change since 2011

Figure 82: Change in the 50th percentile of administered activity for adult perfusion lung scans.

108

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ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 83: Distribution of unit median administered activities from dose assessments performed for adult thyroid
scans with iodine-123.

Table 38: Statistical data associated with the distribution of unit median administered activities from dose
assessments performed for adult thyroid scans with iodine-123.

Thyroid scan (adults)
123

Radiopharmaceutical(s)DRL quantity

I (sodium iodide)

Administered activity (MBq)

DRL in force during data collection (2011 DRL)

10

DRL in force (2019 DRL)

8

Period2016 - 201849

Number of units
DRL quantity

Administered activity (MBq)th

50 percentile

7.8

Minimum – maximum values

4.7 – 13.3

Number of units above the 2011 DRL

12 (24%)

Number of units above the 2019 DRL

23 (47%)ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT109

ADULT NUCLEAR MEDICINETHYROID SCAN (123I)

Change since 2011

Figure 84: Change in the 50th percentile of administered activity for adult thyroid scans with iodine-123.

110

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ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 85: Distribution of unit median administered activities from dose assessments performed for adult thyroid
scans with technetium-99m.

Table 39: Statistical data associated with the distribution of unit median administered activities from dose
assessments performed for adult thyroid scans with technetium-99m.

Thyroid scan (adults)
Radiopharmaceutical(s)99m

DRL quantity

Administered activity (MBq)Tc (sodium pertechnetate)

DRL in force during data collection (2011 DRL)80

DRL in force (2019 DRL)

110

Period2016 - 2018112

Number of units
DRL quantity

Administered activity (MBq)50th percentile

91

Minimum – maximum values

54 - 202

Number of units above the 2011 DRL

81 (72%)

Number of units above the 2019 DRL

41 (37%)ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT111

ADULT NUCLEAR MEDICINETHYROID SCAN (99mTc)

Change since 2011

Figure 86: Change in the 50th percentile of administered activity for adult thyroid scans with technetium-99.

112

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MYOCARDIAL PERFUSION SPECT SCAN (99mTc): 1 DAY

ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 87: Distribution of unit median administered activities for the first injection from dose assessments
performed for 1-day protocol myocardial perfusion SPECT scans with technetium-99m.

Figure 88: Distribution of unit median administered activities per body weight for the first injection from dose
assessments performed for 1-day protocol myocardial perfusion SPECT scans with technetium-99m.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT113

ADULT NUCLEAR MEDICINEMYOCARDIAL PERFUSION SPECT SCAN (99mTc): 1 DAY

Figure 89: Distribution of unit median administered activities for the second injection from dose assessments
performed for 1-day protocol myocardial perfusion SPECT scans with technetium-99m.

Figure 90: Distribution of unit median administered activities per body weight for the second injection from dose
assessments performed for 1-day protocol myocardial perfusion SPECT scans with technetium-99m.

114

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MYOCARDIAL PERFUSION SPECT SCAN (99mTc): 1 DAY

ADULT NUCLEAR MEDICINE

Table 40: Statistical data associated with the distribution of unit median administered activities for the first
injection from dose assessments performed for 1-day protocol myocardial perfusion SPECT scans with technetium99m.

Myocardial perfusion SPECT scan with stress test (dynamic or pharmacological)
99m

Radiopharmaceutical(s)Protocol and injection
DRL quantity
DRL in force during data collection (2011 DRL)DRL in force (2019 DRL)

Tc-MIBI, 99mTc-tetrofosmin

1-day protocol: first injection
Administered activity
Administered activity per body weight(MBq)(MBq/kg)
300
285

3.7

Period2016 - 2018

Number of units

121

121

Administered activity
(MBq)
279

Administered activity per body weight(MBq/kg)
3.6

Minimum – maximum values

126 - 509

1.5 – 6.2

Number of units above the 2011 DRL

32 (26%)-

Number of units above the 2019 DRL

52 (43%)46 (38%)

DRL quantity
50th percentile

Table 41: Statistical data associated with the distribution of unit median administered activities for the second
injection from dose assessments performed for 1-day protocol myocardial perfusion SPECT scans with technetium99m.

Myocardial perfusion SPECT scan with stress test (dynamic or pharmacological)
99m

Radiopharmaceutical(s)Protocol and injection
DRL quantity
DRL in force during data collection (2011 DRL)DRL in force (2019 DRL)

Tc-MIBI, 99mTc-tetrofosmin

1-day protocol: second injection
Administered activity
Administered activity per body weight(MBq)(MBq/kg)
800
785

Period10.3
2016 - 2018

Number of units

118

118

Administered activity
(MBq)
769

Administered activity per body weight(MBq/kg)
10.0

Minimum – maximum values

368 – 1223

4.4 – 15.4

Number of units above the 2011 DRL

42 (36%)-

Number of units above the 2019 DRL

48 (41%)47 (40%)

DRL quantity
50th percentile

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

115

ADULT NUCLEAR MEDICINEMYOCARDIAL PERFUSION SPECT SCAN (99mTc): 1 DAY

Change since 2011

Figure 91: Change in the 50th percentile of the activity administered for the first injection for 1-day protocol
myocardial perfusion SPECT scans with technetium-99m.

Figure 92: Change in the 50th percentile of the activity per body weight administered for the first injection for 1day protocol myocardial perfusion SPECT scans with technetium-99m.

116

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT NUCLEAR MEDICINEMYOCARDIAL PERFUSION SPECT SCAN (99mTc): 1 DAY

Figure 93: Change in the 50th percentile of the activity administered for the second injection for 1-day protocol
myocardial perfusion SPECT scans with technetium-99m.

Figure 94: Change in the 50th percentile of the activity per body weight administered for the second injection for 1day protocol myocardial perfusion SPECT scans with technetium-99m.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT117

ADULT NUCLEAR MEDICINEMYOCARDIAL PERFUSION SPECT SCAN (99mTc): 2 DAYS

Analysis of 2016-2018 data

Figure 95: Distribution of unit median administered activities for the first injection from dose assessments
performed for 2-day protocol myocardial perfusion SPECT scans with technetium-99m.

Figure 96: Distribution of unit median administered activities per body weight for the first injection from dose
assessments performed for 2-day protocol myocardial perfusion SPECT scans with technetium-99m.

118

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTADULT NUCLEAR MEDICINEMYOCARDIAL PERFUSION SPECT SCAN (99mTc): 2 DAYS

Figure 97: Distribution of unit median administered activities for the second injection from dose assessments
performed for 2-day protocol myocardial perfusion SPECT scans with technetium-99m.

Figure 98: Distribution of unit median administered activities per body weight for the second injection from dose
assessments performed for 2-day protocol myocardial perfusion SPECT scans with technetium-99m.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

119

ADULT NUCLEAR MEDICINEMYOCARDIAL PERFUSION SPECT SCAN (99mTc): 2 DAYS

Table 42: Statistical data associated with the distribution of unit median administered activities for the first
injection from dose assessments performed for 2-day protocol myocardial perfusion SPECT scans with technetium99m.

Myocardial perfusion SPECT scan with stress test (dynamic or pharmacological)
99m

Radiopharmaceutical(s)Protocol and injection
DRL quantity
DRL in force during data collection (2011 DRL)DRL in force (2019 DRL)

Tc-MIBI, 99mTc-tetrofosmin

2-day protocol: first injection
Administered activity
Administered activity per body weight(MBq)(MBq/kg)
850
615

7.7

Period2016 - 2018

Number of units
DRL quantity
50th percentile
Minimum – maximum values

19

19

Administered activity
(MBq)
625

Administered activity per body weight(MBq/kg)
7.4

290 - 802

3.9 – 9.9

Number of units above the 2011 DRL

0-Number of units above the 2019 DRL

10 (53%)8 (42%)

Table 43: Statistical data associated with the distribution of unit median administered activities for the second
injection from dose assessments performed for 2-day protocol myocardial perfusion SPECT scans with technetium99m.

Myocardial perfusion SPECT scan with stress test (dynamic or pharmacological)
99m

Radiopharmaceutical(s)Protocol and injection
DRL quantity
DRL in force during data collection (2011 DRL)DRL in force (2019 DRL)

Tc-MIBI, 99mTc-tetrofosmin

2-day protocol: second injection
Administered activity
Administered activity per body weight(MBq)(MBq/kg)
850
615

Period7.7
2016 - 2018

Number of units
DRL quantity
50th percentile
Minimum – maximum values

18

18

Administered activity
(MBq)
597

Administered activity per body weight(MBq/kg)
7.5

289 - 811

3.9 – 10.2

Number of units above the 2011 DRL

0-Number of units above the 2019 DRL

9 (50%)

8 (44%)

Change since 2011
Due to the very low number of dose assessments received each year for 2-day protocol myocardial perfusion SPECT
scans with technetium-99m, it does not seem relevant to present curves where variations are more related to thestatistical inconsistency of data than the change in administered activity over time.

120

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MYOCARDIAL PERFUSION SPECT SCAN (201Tl)

ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 99: Distribution of unit median administered activities for the first injection from dose assessments
performed for myocardial perfusion SPECT scans with thallium-201.

Figure 100: Distribution of unit median administered activities per body weight for the first injection from dose
assessments performed for myocardial perfusion SPECT scans with thallium-201.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

121

ADULT NUCLEAR MEDICINEMYOCARDIAL PERFUSION SPECT SCAN (201Tl)

Figure 101: Distribution of unit median administered activities for the second injection from dose assessments
performed for myocardial perfusion SPECT scans with thallium-201.

Figure 102: Distribution of unit median administered activities per body weight for the second injection from dose
assessments performed for myocardial perfusion SPECT scans with thallium-201.

122

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

201
MYOCARDIAL
MYOCARDIALPERFUSIONPERFUSIONSPECT
SPECTSCAN
SCAN( (201Tl)
Tl)

ADULT
ADULTNUCLEAR
NUCLEARMEDICINEMEDICINE

Table 44: Statistical data associated with the distribution of unit median administered activities for the first
injection from dose assessments performed for myocardial perfusion SPECT scans with thallium-201.

Myocardial perfusion SPECT scan with stress test (dynamic or pharmacological)
201

Radiopharmaceutical(s)Protocol and injection
DRL quantity
DRL in force during data collection (2011 DRL)DRL in force (2019 DRL)

Tl (chloride)

All protocols: first injection
Administered activity
Administered activity per body weight(MBq)(MBq/kg)
110
110

Period

1.4
2016 - 2018

Number of units

26

26

Administered activity
(MBq)
107

Administered activity per body weight(MBq/kg)
1.36

Minimum – maximum values

52 - 143

0.7 – 1.8

Number of units above the 2011 DRL

11 (42%)-

Number of units above the 2019 DRL

10 (38%)9 (35%)DRL quantity
50th percentile

Table 45: Statistical data associated with the distribution of unit median administered activities for the second
injection from dose assessments performed for myocardial perfusion SPECT scans with thallium-201.

Myocardial perfusion SPECT scan with stress test (dynamic or pharmacological)
201

Radiopharmaceutical(s)Protocol and injection
DRL quantity
DRL in force during data collection (2011 DRL)DRL in force (2019 DRL)

Tl (chloride)

All protocols: second injection
Administered activity
Administered activity per body weight(MBq)(MBq/kg)
40
37

Period0.5
2016 - 2018

Number of units

21

21

Administered activity
(MBq)
37

Administered activity per body weight(MBq/kg)
0.48

Minimum – maximum values

16 - 61

0.2 – 0.8

Number of units above the 2011 DRL

5 (24%)-

Number of units above the 2019 DRL

9 (43%)

3 (14%)DRL quantity
50th percentile

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT123

ADULT NUCLEAR MEDICINEMYOCARDIAL PERFUSION SPECT SCAN (201Tl)

Change since 2011

Figure 103: Change in the 50th percentile of the administered activity for the first injection for myocardial perfusion
SPECT scans with thallium-201.

Figure 104: Change in the 50th percentile of the administered activity per body weight for the first injection for
myocardial perfusion SPECT scans with thallium-201.

Due to the very low number of dose assessments received each year for the second injection for myocardial perfusion
SPECT scans with thallium-201, it does not seem relevant to present curves where variations are more related to thestatistical inconsistency of data than the change in administered activity over time.

124

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTRADIONUCLIDE VENTRICULOGRAPHY (LVEF) 99mTc

ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 105: Distribution of unit median administered activities from dose assessments performed for equilibrium
radionuclide ventriculographies (left ventricular ejection fraction measurement) in adults.

Table 46: Statistical data associated with the distribution of unit median administered activities from dose
assessments performed for equilibrium radionuclide ventriculographies (left ventricular ejection fraction
measurement) in adults.

Equilibrium radionuclide ventriculography
for left ventricular ejection fraction measurement (adults)
99m

Radiopharmaceutical(s)DRL quantity

Tc-human serum albumin, 99mTc-red blood cells
Administered activity (MBq)

DRL in force during data collection (2011 DRL)

850

DRL in force (2019 DRL)

740

Period2016 - 201857

Number of units
DRL quantity

Administered activity (MBq)50th percentile

737

Minimum – maximum values

299 - 992

Number of units above the 2011 DRL

9 (16%)

Number of units above the 2019 DRL

27 (47%)ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT

125

ADULT NUCLEAR MEDICINERADIONUCLIDE VENTRICULOGRAPHY (LVEF) 99mTc

Change since 2011

Figure 106: Change in the 50th percentile of the administered activity for equilibrium radionuclide ventriculographies(left ventricular ejection fraction measurement) in adults.

126

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTDYNAMIC RENAL SCAN (99mTc)

ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 107: Distribution of unit median administered activities from dose assessments performed for adult dynamic
renal scans with 99mTc-MAG3 (MAG3 renography).
The distribution of dose assessments for adult dynamic renal scans with 99mTc-DTPA is not shown due to the lack ofdata received (N = 8).

Table 47: Statistical data associated with the distribution of unit median administered activities from dose
assessments performed for adult dynamic renal scans with 99mTc-MAG3 (MAG3 renography).

Renal dynamic scans (adults)
99m

Radiopharmaceutical(s)DRL quantity

Tc-MAG3

Administered activity (MBq)

DRL in force during data collection (2011 DRL)200

DRL in force (2019 DRL)

180

Period2016 - 2018
80

Number of units
DRL quantity

Administered activity (MBq)50th percentile

181

Minimum – maximum values

68 - 410

Number of units above the 2011 DRL

16 (20%)

Number of units above the 2019 DRL

42 (53%)ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT127

ADULT NUCLEAR MEDICINEDYNAMIC RENAL SCAN (99mTc)

Change since 2011

Figure 108: Change in the 50th percentile of administered activity for adult dynamic renal scans with 99mTc-MAG3.
The change in the 50th percentile of the administered activity for adult dynamic renal scans with 99mTc-DTPA is notshown due to the lack of data received.

128

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTBRAIN PERFUSION SPECT SCAN (99mTc)

ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 109: Distribution of unit median administered activities from dose assessments performed for adult brain
perfusion SPECT scans with 99mTc-HMPAO.
The distribution of dose assessments for adult brain perfusion SPECT scans with 99mTc-ECD is not shown due to the lackof data received (N = 3).

Table 48: Statistical data associated with the distribution of unit median administered activities from dose
assessments performed for adult brain perfusion SPECT scans with 99mTc-HMPAO.

Brain perfusion SPECT scans (adults)
99m

Radiopharmaceutical(s)DRL quantity

Tc-HMPAO

Administered activity (MBq)

DRL in force during data collection (2011 DRL)

500

DRL in force (2019 DRL)

695

Period2016 - 201825

Number of units
DRL quantity

Administered activity (MBq)50th percentile662

Minimum – maximum values

442 - 980

Number of units above the 2011 DRL

20 (80%)

Number of units above the 2019 DRL

11 (44%)ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT129

ADULT NUCLEAR MEDICINEBRAIN PERFUSION SPECT SCAN (99mTc)

Change since 2011

Figure 110: Change in the 50th percentile of administered activity for adult brain perfusion SPECT scans with 99mTcHMPAO.
The change in the 50th percentile of the administered activity for adult brain perfusion SPECT scans with 99mTc-ECD is
not shown due to the lack of data received.

130

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTTUMOUR PET (18F-FDG)

ADULT NUCLEAR MEDICINE

Analysis of 2016-2018 data

Figure 111: Distribution of unit median administered activities from dose assessments performed for adult positronemission tomography scans with 18F-fluorodeoxyglucose.

Figure 112: Distribution of unit median administered activities per body weight from dose assessments performed for
adult positron emission tomography scans with 18F-fluorodeoxyglucose.

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORT131

TUMOUR PET (18F-FDG)

ADULT NUCLEAR MEDICINE

Table 49: Statistical data associated with the distribution of unit median administered activities from dose
assessments performed for adult positron emission tomography scans with 18F-fluorodeoxyglucose.

Tumour PET scans (adults)
18

Radiopharmaceutical(s)DRL quantity
DRL in force during data collection (2011 DRL)DRL in force (2019 DRL)

Administered activity
(MBq)
350

F-FDG
Administered activity per body weight(MBq/kg)
-

245

3.5

Period2016 - 2018

Number of units
DRL quantity
50th percentile
Minimum – maximum values

150

150

Administered activity
(MBq)
212

Administered activity per body weight(MBq/kg)
3.0

129 - 401

2.0 – 5.6

Number of units above the 2011 DRL

2 (1%)-

Number of units above the 2019 DRL

39 (26%)37 (25%)

Change since 2011

Figure 113: Change in the 50th percentile of administered activity for adult positron emission tomography scans with
18
F-fluorodeoxyglucose.

Figure 114: Change in the 50th percentile of administered activity per body weight for adult positron emission
tomography scans with 18F-fluorodeoxyglucose.

132

ANALYSIS OF DATA FOR UPDATING DIAGNOSTIC REFERENCE LEVELSIN RADIOLOGY AND NUCLEAR MEDICINE: 2016-2018 REPORTREFERENCE DOCUMENTS(1)Arrêté du 12 février 2004 relatif aux niveaux de référence diagnostiques en radiologie et enmédecine nucléaire. Journal officiel de la République Française du 16 mars 2004.

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