IEC 62220-1-1:2015

IEC 62220-1-1 ®
Edition 1.0 2015-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment – Characteristics of digital X-ray imaging devices –
Part 1-1: Determination of the detective quantum efficiency – Detectors used in
radiographic imaging
Appareils électromédicaux – Caractéristiques des dispositifs d’imagerie à
rayonnement X –
Partie 1-1: Détermination de l'efficacité quantique de détection – Détecteurs
utilisés en imagerie radiographique

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 15
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 60 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,

77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient plus de 30 000 termes et définitions en
Spécifications techniques, Rapports techniques et autres
anglais et en français, ainsi que les termes équivalents dans
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
15 langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
Plus de 60 000 entrées terminologiques électrotechniques, en
La recherche avancée permet de trouver des publications IEC
en utilisant différents critères (numéro de référence, texte, anglais et en français, extraites des articles Termes et
comité d’études,…). Elle donne aussi des informations sur les Définitions des publications IEC parues depuis 2002. Plus
projets et les publications remplacées ou retirées. certaines entrées antérieures extraites des publications des

CE 37, 77, 86 et CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
csc@iec.ch.
IEC 62220-1-1 ®
Edition 1.0 2015-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment – Characteristics of digital X-ray imaging devices –

Part 1-1: Determination of the detective quantum efficiency – Detectors used in

radiographic imaging
Appareils électromédicaux – Caractéristiques des dispositifs d’imagerie à

rayonnement X –
Partie 1-1: Détermination de l'efficacité quantique de détection – Détecteurs

utilisés en imagerie radiographique

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 11.040.50 ISBN 978-2-8322-2389-5

– 2 – IEC 62220-1-1:2015 © IEC 2015
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Requirements . 10
4.1 Operating conditions . 10
4.2 X-RAY EQUIPMENT . 10
4.3 RADIATION QUALITY . 10
4.4 TEST DEVICE . 11
4.5 Geometry . 12
4.6 IRRADIATION conditions . 14
4.6.1 General conditions . 14
4.6.2 AIR KERMA measurement . 15
4.6.3 Avoidance of LAG EFFECTS . 16
4.6.4 IRRADIATION to obtain the CONVERSION FUNCTION. 16
4.6.5 IRRADIATION for determination of the NOISE POWER SPECTRUM . 16
4.6.6 IRRADIATION for determination of the MODULATION TRANSFER FUNCTION . 17
4.6.7 Overview of all necessary IRRADIATIONS . 18
5 Corrections of RAW DATA . 18
6 Determination of the DETECTIVE QUANTUM EFFICIENCY. 19
6.1 Definition and formula of DQE(u,v) . 19
6.2 Parameters to be used for evaluation . 19
6.3 Determination of different parameters from the images . 20
6.3.1 Linearization of data . 20
6.3.2 The NOISE POWER SPECTRUM (NPS) . 20
6.3.3 Determination of the MODULATION TRANSFER FUNCTION (MTF) . 22
7 Format of conformance statement . 24
8 Accuracy . 25
Annex A (normative) Determination of LAG EFFECTS . 26
A.1 Overview. 26
A.2 Estimation of LAG EFFECTS (default method) . 26
A.3 Estimation of LAG EFFECTS, alternative method (only if no LAG EFFECT or
ghosting compensation is applied) . 26
A.3.1 General . 26
A.3.2 Test of additive LAG EFFECTS . 27
A.3.3 Test of multiplicative LAG EFFECTS . 29
A.3.4 Determination of the minimum time between consecutive images . 31
Annex B (informative) Calculation of the input NOISE POWER SPECTRUM. 32
Bibliography . 33
Index of defined terms used in this particular standard . 36

Figure 1 – TEST DEVICE for the determination of the MODULATION TRANSFER FUNCTION
and the magnitude of LAG EFFECTS . 12

Figure 2 – Geometry for exposing the DIGITAL X-RAY IMAGING DEVICE behind the TEST
DEVICE in order to determine LAG EFFECTS and the MODULATION TRANSFER FUNCTION . 14
Figure 3 – Position of the TEST DEVICE for the determination of the MODULATION
TRANSFER FUNCTION . 17
Figure 4 – Geometric arrangement of the ROIs for NPS calculation . 21
Figure 5 – Representation of the image acquired for the determination of the MTF . 23
Figure A.1 – Definition of the ROIs for the test of additive LAG EFFECTS . 28
Figure A.2 – Procedure flow diagram for the test of additive LAG EFFECTS . 28
Figure A.3 – Definition of the ROIs for the test of the multiplicative LAG EFFECTS . 30
Figure A.4 – Procedure flow diagram for the test of multiplicative LAG EFFECTS . 30

Table 1 – RADIATION QUALITY (IEC 61267:2005) for the determination of DETECTIVE
QUANTUM EFFICIENCY and corresponding parameters . 11
Table 2 – Necessary IRRADIATIONS . 18
Table 3 – Parameters mandatory for the application of this standard . 20

– 4 – IEC 62220-1-1:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –
CHARACTERISTICS OF DIGITAL X-RAY IMAGING DEVICES –

Part 1-1: Determination of the detective quantum efficiency –
Detectors used in radiographic imaging

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62220-1-1 has been prepared by subcommittee 62B: Diagnostic
imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice.
This first edition of IEC 62220-1-1 cancels and replaces IEC 62220-1:2003. It constitutes a
technical revision of IEC 62220-1:2003 and assures a better alignment with the other parts of
the IEC 62220 series. The main changes are as follows:
– necessary modifications have been applied as a consequence of taking into account

IEC 61267:2005. This influences HVL values and SNR ;
in
– the method for the determination of LAG EFFECTS now considers lag and ghosting
compensation;
– as part of the MTF determination, the method of obtaining the final averaged MTF has
been restricted (only averaging of the ESF is allowed);

– a description of (optionally) obtaining the diagonal (45°) MTF and NPS has been added.
The text of this standard is based on the following documents:
FDIS Report on voting
62B/968/FDIS 62B/974/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 62220 series, published under the general title Medical electrical
equipment – Characteristics of digital X-ray imaging devices, can be found on the IEC
website.
In this standard, terms printed in SMALL CAPITALS are used as defined in IEC 60788, in Clause
3 of this standard or in other IEC publications referenced in the Index of defined terms. Where
a defined term is used as a qualifier in another defined or undefined term, it is not printed in
SMALL CAPITALS, unless the concept thus qualified is defined or recognized as a “derived term
without definition”.
NOTE Attention is drawn to the fact that, in cases where the concept addressed is not strongly confined to the
definition given in one of the publications listed above, a corresponding term is printed in lower-case letters.
In this standard, certain terms that are not printed in SMALL CAPITALS have particular
meanings, as follows:
– "shall" indicates a requirement that is mandatory for compliance;
– "should" indicates a strong recommendation that is not mandatory for compliance;
– "may" indicates a permitted manner of complying with a requirement or of avoiding the
need to comply;
– "specific" is used to indicate definitive information stated in this standard or referenced in
other standards, usually concerning particular operating conditions, test arrangements or
values connected with compliance;
– "specified" is used to indicate definitive information stated by the manufacturer in
accompanying documents or in other documentation relating to the equipment under
consideration, usually concerning its intended purposes, or the parameters or conditions
associated with its use or with testing to determine compliance.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 62220-1-1:2015 © IEC 2015
INTRODUCTION
DIGITAL X-RAY IMAGING DEVICES are increasingly used in medical diagnosis and are widely
replacing conventional (analogue) imaging devices such as screen-film systems or analogue
X-RAY IMAGE INTENSIFIER television systems. It is necessary, therefore, to define parameters
that describe the specific imaging properties of these DIGITAL X-RAY IMAGING DEVICES and to
standardize the measurement procedures employed.
There is general consensus in the scientific world that the DETECTIVE QUANTUM EFFICIENCY
(DQE) is the most suitable parameter for describing the imaging performance of a DIGITAL X-
RAY IMAGING DEVICE. The DQE describes the ability of the imaging device to preserve the
signal-to-noise ratio from the RADIATION FIELD to the resulting digital image data. Since in X-
ray imaging, the NOISE in the RADIATION FIELD is intimately coupled to the AIR KERMA level, DQE
values can also be considered to describe the dose efficiency of a given DIGITAL X-RAY
IMAGING DEVICE.
NOTE 1 In spite of the fact that the DQE is widely used to describe the performance of imaging devices, the
connection between this physical parameter and the decision performance of a human observer is not yet
completely understood [1], [3].
NOTE 2 IEC 61262-5 specifies a method to determine the DQE of X-RAY IMAGE INTENSIFIERS at nearly zero
SPATIAL FREQUENCY. It focuses only on the electro-optical components of X-RAY IMAGE INTENSIFIERS, not on the
imaging properties as this standard does. As a consequence, the output is measured as an optical quantity
(luminance), and not as digital data. Moreover, IEC 61262-5 prescribes the use of a RADIATION SOURCE ASSEMBLY,
whereas this standard prescribes the use of an X-RAY TUBE. The scope of IEC 61262-5 is limited to X-RAY IMAGE
INTENSIFIERS and does not interfere with the scope of this standard.
The DQE is already widely used by manufacturers to describe the performance of their DIGITAL
X-RAY IMAGING DEVICE. The specification of the DQE is also required by regulatory agencies
(such as the Food and Drug Administration (FDA)) for admission procedures. However, before
the publication of the first edition of this standard there was no standard governing either the
measurement conditions or the measurement procedure, with the consequence that values
from different sources may not be comparable.
This standard has therefore been developed in order to specify the measurement procedure
together with the format of the conformance statement for the DETECTIVE QUANTUM EFFICIENCY
of DIGITAL X-RAY IMAGING DEVICES.
In the DQE calculations proposed in this standard, it is assumed that system response is
measured for objects that attenuate all energies equally (task-independent) [5].
This standard will be beneficial for manufacturers, users, distributors and regulatory agencies.
This first edition of IEC 62220-1-1 forms part of a series of three related standards:
• Part 1-1, which is intended to be used for detectors used in radiographic imaging,
excluding MAMMOGRAPHY and RADIOSCOPY;
• Part 1-2, which is intended to be used for detectors used in MAMMOGRAPHY;
• Part 1-3, which is intended to be used for detectors used in dynamic imaging.
———————
Figures in square brackets refer to the bibliography.

MEDICAL ELECTRICAL EQUIPMENT –
CHARACTERISTICS OF DIGITAL X-RAY IMAGING DEVICES –

Part 1-1: Determination of the detective quantum efficiency –
Detectors used in radiographic imaging

1 Scope
This part of IEC 62220 specifies the method for the determination of the DETECTIVE QUANTUM
EFFICIENCY (DQE) of DIGITAL X-RAY IMAGING DEVICES as a function of AIR KERMA and of SPATIAL
FREQUENCY for the working conditions in the range of the medical application as specified by
the MANUFACTURER. The intended users of this part of IEC 62220 are manufacturers and well
equipped test laboratories.
NOTE 1 While not recommended, applying this standard to determine the DQE of digital X-ray imaging devices
integrated in a clinical system is not excluded as long as the requirements as set in this standard are respected.
Points of additional attention could be (for example but not exclusively) the establishment of the required RADIATION
QUALITIES, minimizing influences of scattered and back-scattered radiation, accurate AIR KERMA measurements,
positioning of the TEST DEVICE, presence of protective covers, removal of ANTI-SCATTER GRID.
This Part 1-1 is restricted to DIGITAL X-RAY IMAGING DEVICES that are used for radiographic
imaging such as, but not exclusively, CR systems, direct and indirect flat panel-detector
based systems.
It is not recommended to use this part of IEC 62220 for digital X-RAY IMAGE INTENSIFIER-based
systems.
NOTE 2 The use of this standard for X-RAY IMAGE INTENSIFER-based systems is discouraged based on the low
frequency drop, vignetting and geometrical distortion present in these devices which may put severe limitations on
the applicability of the measurement methods described in this standard.
This part of IEC 62220 is not applicable to:
– DIGITAL X-RAY IMAGING DEVICES intended to be used in mammography or in dental
radiography;
– slot scanning DIGITAL X-RAY IMAGING DEVICES;
– COMPUTED TOMOGRAPHY;
– devices for dynamic imaging (where series of images are acquired, as in fluoroscopy or cardiac
imaging).
NOTE 3 The devices noted above are excluded because they contain many parameters (for instance, beam
qualities, geometry, time dependence, etc.) which differ from those important for RADIOGRAPHY. Some of these
techniques are treated in other parts of the IEC 62220 standards (IEC 62220-1-2 and IEC 62220-1-3).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60336, Medical electrical equipment – X-ray tube assemblies for medical diagnosis –
Characteristics of focal spots
IEC TR 60788:2004, Medical electrical equipment – Glossary of defined terms

– 8 – IEC 62220-1-1:2015 © IEC 2015
IEC 61267:2005, Medical diagnostic X-ray equipment – Radiation conditions for use in the
determination of characteristics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60788:2004 and the
following apply.
3.1
CALIBRATION CONDITIONS
set of conditions under which calibration is done
3.2
CENTRAL AXIS
line perpendicular to the ENTRANCE PLANE passing through the centre of the ENTRANCE FIELD
3.3
CONVERSION FUNCTION
plot of the large area output level (ORIGINAL DATA) of a DIGITAL X-RAY IMAGING DEVICE versus
the number of exposure quanta per unit area (Q) in the DETECTOR SURFACE plane
Note 1 to entry: Q is to be calculated by multiplying the measured AIR KERMA excluding back scatter by the value
given in column 2 of Table 3.
3.4
DETECTIVE QUANTUM EFFICIENCY
DQE
DQE(u,v)
ratio of two NOISE POWER SPECTRUM (NPS) functions with the numerator being the NPS of the
DETECTOR SURFACE of a digital X-ray detector after having gone through the
input signal at the
deterministic filter given by the system transfer function, and the denominator being the
measured NPS of the output signal (ORIGINAL DATA)
Note 1 to entry: Instead of the two-dimensional DETECTIVE QUANTUM EFFICIENCY, often a cut through the two-
dimensional DETECTIVE QUANTUM EFFICIENCY along a specified SPATIAL FREQUENCY axis is published.
Note 2 to entry: The note to entry concerning the origin of the abbreviation "DQE" concerns the French text only.
3.5
DETECTOR SURFACE
accessible area which is closest to the IMAGE RECEPTOR PLANE
Note 1 to entry: After removal of all parts (including the ANTI-SCATTER GRID and components for AUTOMATIC
EXPOSURE CONTROL, if applicable) that can be safely removed from the RADIATION BEAM without damaging the digital
X-ray detector.
3.6
DIGITAL X-RAY IMAGING DEVICE
device consisting of a digital X-ray detector including the protective layers installed for use in
practice, the amplifying and digitizing electronics, and a computer providing the ORIGINAL DATA
(DN) of the image
Note 1 to entry: This may include protecting parts, such as ANTI-SCATTER GRIDS and components for AUTOMATIC
.
EXPOSURE CONTROL
3.7
IMAGE MATRIX
arrangement of matrix elements preferentially in a Cartesian coordinate system

3.8
LAG EFFECT
influence from a previous image on the current one
3.9
LINEARIZED DATA
ORIGINAL DATA to which an inverse CONVERSION FUNCTION has been applied
Note 1 to entry: LINEARIZED DATA are directly proportional to the AIR KERMA under the specific CALIBRATION
CONDITIONS used.
Note 2 to entry: This is the data type that best indicates the fundamental performance of the detector and should
be the data type used for “physics” testing of systems.
3.10
MODULATION TRANSFER FUNCTION
MTF(u,v)
modulus of the generally complex optical transfer function, expressed as a function of SPATIAL
u and v
FREQUENCIES
Note 1 to entry: The note to entry concerning the origin of the abbreviation «MTF» concerns the French text only.
3.11
NOISE
fluctuations from the expected value of a stochastic process
3.12
NOISE POWER SPECTRUM
NPS
W(u,v)
modulus of the Fourier transform of the NOISE auto-covariance function; the power of NOISE,
contained in a two-dimensional SPATIAL FREQUENCY interval, as a function of the two-
dimensional frequency
Note 1 to entry: In the literature, the NOISE POWER SPECTRUM is often named “Wiener spectrum” in honour of the
mathematician Norbert Wiener.
Note 2 to entry: The note to entry concerning the origin of the abbreviation «NPS» concerns the French text only.
3.13
ORIGINAL DATA
DN
RAW DATA that has been processed to account for detector and x-ray system limitations as
allowed in this standard
Note 1 to entry: The relation of the ORIGINAL DATA to the IMAGE RECEPTOR AIR KERMA may include a non-linear,
e.g., logarithmic or square-root characteristic. If so, an inverse CONVERSION FUNCTION should be supplied to
produce LINEARIZED DATA.
3.14
PHOTON FLUENCE
Q
mean number of photons per unit area
3.15
PRECISION
closeness of agreement between independent test results obtained under stipulated
conditions
[SOURCE: ISO 5725-1:1994, 3.12, modified – the three notes in the original definition have
been deleted.]
– 10 – IEC 62220-1-1:2015 © IEC 2015
3.16
RAW DATA
PIXEL values read directly after the analogue-digital-conversion from the DIGITAL X-RAY IMAGING
DEVICE or counts from photon counting systems that have not undergone any modification
whose intent is to account for detector or x-ray system limitations
Note 1 to entry: Depending on system design, this data may not be accessible.
3.17
SPATIAL FREQUENCY
u or v
inverse of the period of a repetitive spatial phenomenon
Note 1 to entry: The dimension of the SPATIAL FREQUENCY is inverse length.
4 Requirements
4.1 Operating conditions
The DIGITAL X-RAY IMAGING DEVICE shall be stored and operated according to the
MANUFACTURER’S recommendations. The warm-up time shall be chosen according to the
recommendation of the MANUFACTURER. The operating conditions shall be the same as those
intended for clinical use and shall be maintained during evaluation as required for the specific
tests described herein.
Ambient climatic conditions in the room where the DIGITAL X-RAY IMAGING DEVICE is operated
shall be stated together with the results.
4.2 X-RAY EQUIPMENT
For all tests described in the following subclauses, a CONSTANT POTENTIAL HIGH-VOLTAGE
GENERATOR is recommended (IEC 60601-2-54 [36]). The PERCENTAGE RIPPLE shall be equal to,
or less than, 4.
The NOMINAL FOCAL SPOT VALUE (IEC 60336) shall be not larger than 1,2.
For the measuring of AIR KERMA, calibrated RADIATION METERS shall be used. The uncertainty
(coverage factor 2) [2] of the measurements shall be less than 5 %.
NOTE “Uncertainty” and “coverage factor” are terms defined in the ISO/IEC Guide to the expression of uncertainty
in measurement [2].
4.3 RADIATION QUALITY
The RADIATION QUALITIES shall be one or more of four selected RADIATION QUALITIES specified in
IEC 61267:2005 (see Table 1). If only a single RADIATION QUALITY is used, RADIATION QUALITY
RQA5 should be preferred.
NOTE 1 This first edition of IEC 62220-1-1 (which replaces the first edition of IEC 62220-1:2003) has changed its
reference to the second edition of IEC 61267:2005 to establish the RADIATION QUALITIES. As a consequence of
these changes in the RADIATION QUALITIES, the values of the input NOISE POWER SPECTRUM have been changed. New
values are given in Table 1 and Table 3.
For this standard the RADIATION QUALITIES shall be established by setting a fixed X-RAY TUBE
VOLTAGE as defined in Table 1 and adapting the ADDITIONAL FILTRATION (starting with the
values as given in Table 1) until the correct HVL is reached with an uncertainty of ±2 %. This
procedure is in line with 6.5 of IEC 62167:2005.
While IEC 61267:2005 requires the measurement of X-RAY TUBE VOLTAGE invasively in terms
of the practical peak voltage (PPV), this standard allows for non-invasive measurement of

PPV and in cases when the X-RAY GENERATOR is a CONSTANT POTENTIAL HIGH-VOLTAGE
GENERATOR, the use of traditional kVp measurement. These X-RAY TUBE VOLTAGE
measurements shall be performed using the RADIATION BEAM without the ADDITIONAL
FILTRATION. As given in IEC 61267:2005 the X-RAY TUBE VOLTAGE shall be within an
uncertainty of 1,5 kV or 1,5 %, whichever is larger.
NOTE 2 Commercial non-invasive X-RAY TUBE VOLTAGE measuring devices are available that support PPV
measurements as well as traditional kVp measurements.
Table 1 – RADIATION QUALITY (IEC 61267:2005) for the determination
of DETECTIVE QUANTUM EFFICIENCY and corresponding parameters
X-RAY TUBE VOLTAGE HALF-VALUE LAYER (HVL) Approximate ADDITIONAL
RADIATION QUALITY No.
FILTRATION
kV mm Al mm Al
RQA 3 50 3,8 10,0
RQA 5 70 6,8 21,0
RQA 7 90 9,2 30,0
RQA 9 120 11,6 40,0
NOTE 3 The ADDITIONAL FILTRATION is the filtration added to the inherent filtration of the X-RAY TUBE.
The capability of X-RAY GENERATORS to produce low AIR KERMA levels may not be sufficient,
especially for RQA9. In this case, it is recommended that the FOCAL SPOT to DETECTOR
SURFACE distance be increased.
IEC 61267:2005 requires the purity of the aluminium used for the additional filtration to be at
least 99,9 %. It has been shown [15] that these kinds of high purity aluminium metals are
prone to kinds of non-uniformities which can significantly impact the NPS and hence the DQE
determination. It is therefore recommended, contrary to the requirements given in
IEC 61267:2005, to use lower purity aluminium filtration (99 % purity, also designated as type-
1100).
4.4 TEST DEVICE
The TEST DEVICE for the determination of the MODULATION TRANSFER FUNCTION and the
magnitude of LAG EFFECTS shall consist of a 1,0 mm thick tungsten plate (purity higher than
90 %) at least 100 mm long and at least 75 mm wide (see Figure 1). Inadequate purity of
tungsten shall be compensated by increased thickness.
The tungsten plate is used as an edge TEST DEVICE. Therefore, the edge which is used for the
test IRRADIATION shall be carefully polished straight and at 90° to the plate. If the edge is
irradiated by X-rays in contact with a screenless film, the image on the film shall show no
ripples on the edge larger than 5 µm.
The tungsten plate shall be fixed on a 3 mm thick lead plate (see Figure 1). This arrangement
is suitable to measure the MODULATION TRANSFER FUNCTION of the DIGITAL X-RAY IMAGING
DEVICE in one direction.
– 12 – IEC 62220-1-1:2015 © IEC 2015
b
X-ray
d
DETECTOR SURFACE
f
(1) W
(1) W
(2) Pb
IEC
The TEST DEVICE consists of a tungsten plate (1) fixed on a lead plate (2). Dimension of the lead plate: a: 200 mm,
b: 100 mm, c: 90 mm, d: 70 mm, g: 3 mm. Dimension of the tungsten plate: e: 100 mm, f: 75 mm, h: 1 mm.
Figure 1 – TEST DEVICE for the determination of the MODULATION
TRANSFER FUNCTION and the magnitude of LAG EFFECTS
4.5 Geometry
The geometrical set-up of the measuring arrangement shall comply with Figure 2. The X-RAY
EQUIPMENT is used in that geometric configuration in the same way as it is used for normal
diagnostic applications. The distance between the FOCAL SPOT of the X-RAY TUBE and the
DETECTOR SURFACE should be not less than 1,50 m. If, for technical reasons, the distance
cannot be 1,50 m or more, a smaller distance can be chosen but has to be explicitly declared
REFERENCE AXIS shall be aligned with the CENTRAL AXIS.
when reporting results. The
This means that the line perpendicular to the ENTRANCE PLANE passing through the centre of
the ENTRANCE FIELD shall be aligned with the line in the reference direction through the centre
of the RADIATION SOURCE. The TEST DEVICE is placed immediately in front of the DETECTOR
SURFACE. The centre of the edge of the TEST DEVICE should be aligned to the REFERENCE AXIS
of the X-ray beam. Displacement from the REFERENCE AXIS will lower the measured MTF. The
REFERENCE AXIS can be located by maximizing the MTF as a function of TEST DEVICE
displacement.
The recommended procedure is that the TEST DEVICE and the X-ray field be centred on the
detector. If this is not done, the position of the centre of the X-ray field and of the TEST DEVICE
shall be stated.
In the set-up of Figure 2, the DIAPHRAGM B1 and the ADDED FILTER shall be positioned near the
FOCAL SPOT of the X-RAY TUBE.
IEC 61267:2005 requires that the ADDED FILTER be placed between 200 mm and 300 mm from
the FOCAL SPOT of the X-RAY TUBE. Due to SCATTERED RADIATION from the ADDED FILTER, this is
however not the optimal distance for the intended use as given in this standard, as it will
lower the measured MTF. Therefore, contrary to the requirement as given in IEC 61267:2005,
it is recommended to keep the distance between the ADDED FILTER and the FOCAL SPOT of the
X-RAY TUBE as small as possible. The DIAPHRAGMS B2 and B3 may be used to reduce the
a
c
g
e
h
effect from SCATTERED RADIATION generated in the ADDED FILTER that will adversely affect the
MTF determination. The DIAPHRAGMS B1 and - if applicable - B2 and the ADDED FILTER shall be
in a fixed relation to the position of the FOCAL SPOT. The DIAPHRAGM B3 − if applicable − and
the DETECTOR SURFACE shall be in a fixed relation at each distance from the FOCAL SPOT.
DIAPHRAGM B3 – if applicable – shall be 120 mm in front of the DETECTOR SURFACE and shall
be of a size to allow an irradiated field at the DETECTOR SURFACE of at least
160 mm × 160 mm. The RADIATION APERTURE of DIAPHRAGM B2 may be made variable so that
the beam remains tightly collimated as the distance is changed. The irradiated field at the
DETECTOR SURFACE shall be at least 160 mm × 160 mm. All DIAPHRAGMS shall be square in
shape.
The attenuating properties of the DIAPHRAGMS shall be such that their transmission into
shielded areas does not contribute to the results of the measurements. The RADIATION
APERTURE of the DIAPHRAGM B1 shall be large enough so that the PENUMBRA of the RADIATION
BEAM will be outside the sensitive volume of the monitor detector R1 and the RADIATION
APERTURE of DIAPHRAGM B2 – if applicable.
A monitor detector should be used to assure the PRECISION of the X-RAY GENERATOR. The
monitor detector R1 may be inside the beam that irradiates the DETECTOR SURFACE if it is
suitably transparent and free of structure; otherwise, it shall be placed outside of that portion of
the beam that passes DIAPHRAGM B3. The PRECISION (standard deviation 1σ) of the monitor
detector shall be better than 2 %. The relationship between the monitor reading and the AIR
KERMA at the DETECTOR SURFACE shall be calibrated for each RADIATION QUALITY used (see also
4.6.2). In addition, the calibration of the monitor detector may be sensitive to the positioning
of the ADDED FILTER and to the adjustment of the shutters built into the X-ray source.
Therefore, these items should not be altered without re-calibrating the relationship between
the monitor reading and the AIR KERMA at the DETECTOR SURFACE.
This geometry is used without TEST DEVICE to irradiate the DETECTOR SURFACE for the
determination of the CONVERSION FUNCTION and the NOISE POWER SPECTRUM (see 4.6.4 and
4.6.5) or to irradiate the DETECTOR SURFACE behind the TEST DEVICE for the determination of
the MTF and LAG EFFECTS (see 4.6.3 and 4.6.6).
For all measurements, the same area of the DETECTOR SURFACE shall be irradiated (exception
see 4.6.6). The centre of this area, with respect to either the centre or the border of the
DIGITAL X-RAY DEVICE, shall be recorded.
All measurements related to one RADIATION QUALITY shall be made using the same geometry.
As stated in 4.3, the capability of X-RAY GENERATORS to produce low AIR KERMA levels may not
be sufficient, especially for RQA9, and it is recommended that the FOCAL SPOT to DETECTOR
SURFACE distance be increased in this case. To comply with the requirement as given above, it
is therefore recommended to first determine the correct FOCAL SPOT to DETECTOR SURFACE
distance before starting the measurements.

– 14 – IEC 62220-1-1:2015 © IEC 2015
FOCAL
SPOT
DIAPHRAGM B1
ADDED FILTER
Monitor detector R1
(optional)
DIAPHRAGM B2
(optional)
DIAPHRAGM B3
(optional)
TEST DEVICE
DETECTOR SURFACE c
IEC
To determine the CONVERSION FUNCTION and the NOISE POWER SPECTRUM the same geometry is used but the TEST
DEVICE shall be moved out of the beam. The minimal distance between the FOCAL SPOT and the DETECTOR SURFACE,
a = 1,5 m. The distance between DIAPHRAGM B3 and the DETECTOR SURFACE, b = 120 mm. The minimal irradiated
field at the DETECTOR SURFACE, c = 160 × 160 mm .
Figure 2 – Geometry for exposing the DIGITAL X-RAY IMAGING DEVICE behind the TEST
DEVICE in order to determine LAG EFFECTS and the MODULATION TRANSFER FUNCTION
4.6 IRRADIATION conditions
4.6.1 General conditions
The calibration of the digital X-ray detector shall be carried out prior to any testing, i.e., all
operations necessary for corrections according to Clause 5 shall be effected. The whole
series of measurements shall be done without re-calibration. Offset calibrations are excluded
from this requirement. They can be performed as in normal clinical use.
a
b
The AIR KERMA level shall be chosen as that used when the DIGITAL X-RAY IMAGING DEVICE is
operated for the intended use in clinical practice. This is called the “normal“ level. At least two
additional AIR KERMA levels shall be chosen, one approximately 3,2 times the normal level and
one at approximately 1/3,2 of the normal level. No change of settings of the DIGITAL X-RAY
IMAGING DEVICE (such as gain etc.) shall be allowed when changing AIR KERMA levels.
Mentioned factor 3,2 (corresponding to 5 steps on the R10 scale – ISO 3) shall be reached as
close as possible taking the capabilities of the used X-RAY GENERATOR into account. The factor
shall be not less than 3.
NOTE A factor of three in the AIR KERMA above and below the “normal” level approximately corresponds to the
br
...