Radiation Protection Dosimetry
Vol. 80, Nos 1–3, pp. 95–97 (1998)
Nuclear Technology Publishing
GUIDELINES FOR QUALITY CONTROL OF EQUIPMENT USED
IN DIAGNOSTIC RADIOLOGY IN THE NETHERLANDS
Abstract — The Dutch working group on ‘Quality Criteria for Equipment Used in Diagnostic Radiology’ has formulated guidelines providing technical criteria for equipment used in conventional diagnostic radiology. These guidelines are applicable to the
technical parameters having a major impact on image quality and patient dose and include methods for testing. The following
parameters are included: tube voltage, automatic exposure control, film processing, film–screen combination, light tightness and
illumination of the dark room, half-value layer and filtration, light field, grid, focal spot size, viewing boxes and geometrical
indicators. Each guideline consists of the following chapters: (1) Scope and field of application, (2) Background information,
(3) Test procedure, (4) Test frequency, (5) Registration of observations, (6) Evaluation and interpretation, (7) Test report. Chapter
3 includes both the principles of the test method and a step by step description of the procedures. The principles of the test
procedure provide a basis for adaptation to local circumstances. The step by step test procedure allows a quality control measurement to be performed with limited physical knowledge of the equipment. Chapter 6 includes limiting values. Draft guidelines
were evaluated in practice in 20 hospitals. The final document has been accepted by the professional societies in the Netherlands
and the Dutch Minister of Health as a reference set of tools to perform Quality Control of equipment used for conventional
diagnostic radiology.
INTRODUCTION
the aim of formulating guidelines for quality control
(QC). Each guideline should include criteria for
technical parameters and accompanying measurement
methods. The activities and achievements of the working group are here presented.
The Council Directive 84/466/Euratom (1) regarding
the radiation protection of persons undergoing medical
examination or treatment (Patient Directive) has been
transposed into Dutch law. This was achieved by an
amendment (2), dated 25 May 1993, to the Dutch Decree
on Radiation Protection of 10 September 1986 (3). In an
annex to this amendment, technical criteria are included
for equipment used in diagnostic radiology. In addition
to the formal introduction of the ‘Patient Directive’, the
Dutch Ministry of Health, Welfare and Sports (VWS)
is promoting various activities to help implementation
of the legal provisions. One of these activities, concerning diagnostic radiology, was to extend the technical criteria for equipment since, (i) criteria for only five technical parameters are included in the annex; and (ii) no
measurement methods are indicated or referred to.
Therefore, the Ministry of VWS invited (professional)
societies to participate in a working group on ‘Quality
criteria for equipment used in diagnostic radiology’ with
WORKING GROUP ACTIVITIES
Four (professional) societies which are active in the
field of diagnostic radiology (Table 1) participated in
the working group. Scientific and secretarial support to
Table 1. Professional societies in the field of diagnostic
radiology.
The Netherlands Society for Radiology
The Netherlands Society of Radiographers and
Radiological Technologists
The Netherlands Society for Radiological Protection
The Netherlands Society for Clinical Physics
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L. van den Berg(1), J. C. N. M. Aarts(2), L. B. Beentjes(3), A. van Dalen(4), P. Elsakkers(5), H. W. Julius(1),
P. J. H. Kicken(6), F. van der Meer(7), W. Teeuwisse(5), M. A. O. Thijssen(8) and J. Zoetelief(1)
(1)
TNO Centre for Radiological Protection and Dosimetry
PO Box 9034, 6800 ES Arnhem, The Netherlands
(2)
Stg. Deventer Ziekenhuis, Lokatie St. Geertruiden Gasthuis
PO Box 5001, 7400 GC Deventer, The Netherlands
(3)
Schelstraeteweg 13, 6525 SZ Nijmegen, The Netherlands
(4)
Centraal Militair Hospitaal, Afdeling Radiodiagnostiek, PO Box 90000, 3509 AA Utrecht, The Netherlands
(5)
Acad. Ziekenhuis Leiden, Afdeling Radiodiagnostiek
geb 1, C2-S
PO Box 9060, 2300 RC Leiden, The Netherlands
(6)
AZR, Daniel den Hoed Kliniek, Stralingsbeschermingsdienst
PO Box 5201, 3008 AE Rotterdam, The Netherlands
(7)
Acad. Ziekenhuis Rotterdam Dijkzigt, Afd. Radiodiagnostiek – CID
Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
(8)
Academisch Ziekenhuis Nijmegen, Afdeling Radiodiagnostiek
PO Box 9101, 6500 HB Nijmegen, The Netherlands
L. VAN DEN BERG et al
STRUCTURE AND CONTENTS OF THE
GUIDELINES
The guidelines can be used in different ways, dependent on the experience of the reader. By following the
successive chapters (Table 3) a rather inexperienced
user obtains information on:
(i) technical and physical aspects of the parameter(s),
(ii) the impact of the parameter(s) on image quality and
patient dose,
(iii) the principles of the measurement method and a
step by step procedure for performing the test,
(iv) registration of the results of measurements and calculations,
(v) evaluation of the results and corrective actions
where necessary.
A more experienced user can easily apply the guidelines
by using the measurement equipment, the step by step
method and the registration forms. The most experienced users, e.g. persons responsible for QC, can adapt
the step by step method to the local situation. If the
adaptation is in accordance with the principles of the
measurement method, the accompanying limiting values
are still applicable. The most essential aspects of the
guidelines are the limiting values and the measurement
methods for the eleven parameters (Table 2). When the
measurement results are in compliance with the limiting
values no noticeable deviation in image quality or in
patient dose is to be expected. The guidelines also
Table 2. Technical parameters influencing the performance of X ray equipment with the accompanying limiting values
and measurement methods.
Parameter
Limiting values
Tube voltage
Automatic exposure control
5% accuracy; 2.5% precision.
Optical density of the film between 1.10
OD and 1.50 OD.
Maximal deviation fog ± 0.05 OD; speed
and contrast ± 0.15 OD.
Maximal deviation of the same speed class
± 0.10 OD; no artefacts.
Film processing
Film–screen combination
Light tightness and illumination
of the darkroom
Half-value layer and filtration
Light beam alignment
Grid
Focal spot size
Viewing boxes
Geometrical indicators of the
X ray unit
Measurement method or equipment
Electronic kVp meter.
Exposing film at selected tube voltages and
thickness of the PMMA phantom.
Constancy test using film exposed with a
sensitometer.
Exposure of 4 films simultaneously to a given
radiation quality, e.g. 80 kV and 25 mm Al
filter.
Maximal increment 0.10 OD after 4 min
Film, pre-exposed with a sensitometer, kept to
exposure of a pre-exposed film.
various darkroom conditions.
Inherent filtration ⬎2.5 mm Alequivalent. It is Measurement of the HVL at 80 kV and use of
recommended to add Cu filter for
look-up diagrams for filtration.
⬎100 kV.
Edges light and X ray beam within 1%
Use of a specific alignment phantom.
focus–film distance.
Transmission factor ⬎64%; ratio 6:1, grid Dose measurements of primary and scattered
factor ⬍3; no artefacts.
radiation in the presence and the absence of
the grid.
In compliance with the specification of the Star pattern phantom according to the IECmanufacturer.
336.
cd.m−2 meter for brightness of the viewing
⬎ 3000 cd.m−2 and 25% homogeneity;
ambient light sources ⬍25 lux.
box; lux meter for ambient light.
Readouts ⬍1 cm; ⬍1°; orthogonality
Centimetre, angle meter and orthogonality
X ray beam to table ⬍1°.
phantom.
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the working group was given by the TNO Centre for
Radiological Protection and Dosimetry. The working
group aimed at the establishment of guidelines including
limiting values and measurement methods for conventional installations in the Dutch language. Based on the
literature and the experience of the members of the
working group, eleven technical parameters having a
major impact on image quality and patient dose were
selected (Table 2). The limiting values for these parameters are based on values recommended in internationally accepted standards, for instance those from
the International Electrotechnical Commission (IEC) (4).
The measurement methods were selected on the basis
of simplicity, time and cost effectiveness.
Most measurement methods, as described in international guidelines, are appropriated in a technical setting but were not considered to be easily applicable in
a clinical situation.
Drafts of the guidelines were tested by radiographers,
instrumental engineers and medical physicists in 20
departments of radiology of university and peripheral
hospitals. These tests resulted in all types of comment
which were implemented in the guidelines where appropriate.
In September 1997 about 400 copies of the final version of the guidelines were distributed among the boards
of directors of health institutes having a diagnostic
X ray installation, and among all diagnostic radiology
departments in the Netherlands.
GUIDELINES FOR QUALITY CONTROL IN THE NETHERLANDS
include annexes on definition on terms, measurement
equipment, phantoms and registration forms.
an acceptance test is carried out and appropriate QC
programmes are implemented by the holder of the radiological installation. The professional societies and the
Minister of Health in the Netherlands consider these
guidelines to be a valuable instrument for QC of equipment used in diagnostic radiology. The Minister of
Health recommends that holders of radiological installations gain experience with these guidelines to be able
to meet future requirements. (5) As mentioned before, the
guidelines are restricted to conventional X ray installations. For other types of radiological equipment, such
as computed tomography systems, fluoroscopy and digital imaging systems additional guidelines should also
be formulated.
CONCLUSIONS AND FUTURE DEVELOPMENTS
The working group has formulated 11 guidelines for
Quality Control of conventional diagnostic radiology
installations and accessories (film–screen combination,
dark room, film processor and viewing boxes). The
guidelines include limiting values and measurement
methods.
The new European patient directive (97/43/
Euratom) (5) states that Member States shall ensure that
Chapter
Contents
1. Scope and field of application
2. Background information
Aims and types of apparatus
Information on physical and technical aspects and impact on image
quality and patient dose
Principles of the test method; a step by step description of the
method, including a list of instrumentation
Time interval between tests
Registration of measurement results
Calculations; comparison of results with limiting values; corrective
actions; trend analysis
Test report with a completed registration form
3. Test procedures
4. Test frequency
5. Registration of observations
6. Evaluation and interpretation
7. Test report
REFERENCES
1. European Commission. Council Directive of 3 September 1984 (84/466/Euratom) laying down the Basic Measures for the
Radiation Protection of Persons undergoing Medical Examination or Treatment. Official Journal of the European Communities
No L 265 (1984).
2. Decree of 25 May 1993. Amendment of Decree on Radiation Protection. Official Journal of the Netherlands 317 (1993).
3. Decree of 10 September 1986. Enforcement of the Articles 28 up to and including 32 and the Application of Article 34 of
the Atomic Energy Act (Decree on Radiation Protection Atomic Energy Act). Official Journal of the Netherlands 465 (1986).
4. Technical Committee No 62B of the International Electrotechnical Commission. X-ray equipment operating up to 400 kV and
accessories. Quality Assurance in Diagnostic X-ray Departments, Evaluation and Routine Testing in Medical Imaging Departments; Part 2–11: Constancy Tests — Equipment for General Direct Radiography. IEC Publications 1223-1-11 (1995).
5. European Commission. Council Directive 97/43/Euratom of 30 June 1997 on Health Protection of Individuals against the
Dangers of Ionizing Radiation in Relation to Medical Exposure, and Repealing Directive 84/466/Euratom. Official Journal
of the European Communities No L 180/22 (1997).
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Table 3. Structure of the guidelines.