EN 62494-1:2008

SLOVENSKI STANDARD
01-januar-2009
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Medical electrical equipment - Exposure index of digital X-ray imaging systems - Part 1:
Definitions and requirements for general radiography (IEC 62494-1:2008 )
Medizinische elektrische Geräte - Dosisindikator digitaler Röntgenbildsysteme - Teil 1:
Definitionen und Anforderungen für die allgemeine Radiographie (IEC 62494-1:2008 )
Appareils électro-médicaux - Indice d'exposition des systèmes d’imagerie numérique à
rayonnement X - Partie 1: Définitions et exigences pour la radiographie générale (CEI
62494-1:2008 )
Ta slovenski standard je istoveten z: EN 62494-1:2008
ICS:
11.040.50 Radiografska oprema Radiographic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62494-1
NORME EUROPÉENNE
November 2008
EUROPÄISCHE NORM
ICS 11.040.50
English version
Medical electrical equipment -
Exposure index of digital X-ray imaging systems -
Part 1: Definitions and requirements for general radiography
(IEC 62494-1:2008)
Appareils électromédicaux -  Medizinische elektrische Geräte -
Indice d'exposition des systèmes Dosisindikator digitaler
d’imagerie numérique à rayonnement X - Röntgenbildsysteme -
Partie 1: Définitions et exigences Teil 1: Definitionen und Anforderungen
pour la radiographie générale für die allgemeine Radiographie
(CEI 62494-1:2008) (IEC 62494-1:2008)

This European Standard was approved by CENELEC on 2008-10-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62494-1:2008 E
Foreword
The text of document 62B/680/CDV, future edition 1 of IEC 62494-1, prepared by SC 62B, Diagnostic
imaging equipment, of IEC TC 62, Electrical equipment in medical practice, was submitted to the
IEC-CENELEC parallel vote and was approved by CENELEC as EN 62494-1 on 2008-10-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-10-01
In this standard, the following print types are used:
– requirements, compliance with which can be tested, and definitions: in roman type;
– explanations, advice, notes, general statements, exceptions and references: in smaller type;
– TERMS DEFINED IN CLAUSE 3 OF THIS STANDARD, IN EN 60601-1 OR IN IEC/TR 60788, AS REFERENCED IN
THE INDEX OF DEFINED TERMS: SMALL CAPITALS.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62494-1:2008 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60601-1 NOTE  Harmonized as EN 60601-1:2006 (not modified).
IEC 60601-2-43 NOTE  Harmonized as EN 60601-2-43:2000 (not modified).
IEC 62220-1 NOTE  Harmonized as EN 62220-1:2004 (not modified).
IEC 62220-1-2 NOTE  Harmonized as EN 62220-1-2:2007 (not modified).
__________
– 3 – EN 62494-1:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC/TR 60788 2004 Medical electrical equipment - Glossary of - -
defined terms
IEC 62494-1
Edition 1.0 2008-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment – Exposure index of digital X-ray imaging
systems –
Part 1: Definitions and requirements for general radiography

Appareils électromédicaux – Indice d'exposition des systèmes d’imagerie
numérique à rayonnement X –
Partie 1: Définitions et exigences pour la radiographie générale

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
R
CODE PRIX
ICS 11.040.50 ISBN 2-8318-9944-3
– 2 – 62494-1 © IEC:2008
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.7
2 Normative references .7
3 Terms and definitions .7
4 Requirements .9
4.1 Creation of ORIGINAL DATA.9
4.2 Determination of the RELEVANT IMAGE REGION and the VALUE OF INTEREST .9
4.3 Requirements for the EXPOSURE INDEX .10
4.4 Calibration of the EXPOSURE INDEX .10
4.5 Determination of the CALIBRATION FUNCTION .11
4.6 Determination of the INVERSE CALIBRATION FUNCTION .11
4.7 Requirements for the DEVIATION INDEX.11
Annex A (informative) Details on the rationale, properties and use of the EXPOSURE
INDEX .13
Annex B (informative) Details on the rationale, properties and use of the DEVIATION
INDEX .17
Annex C (normative) Beam conditions to be used for calibration.18
Bibliography.19
Terminology – Index of defined terms .20

Figure A.1 – Example of an ORIGINAL DATA radiograph with an example of the RELEVANT
IMAGE REGION outlined .14
Figure A.2 – Histogram of the ORIGINAL DATA for the radiograph shown in Figure A.1 .15
Figure A.3 – Relative IMAGE RECEPTOR AIR KERMA required to produce a fixed detector
response for the four x-ray beam qualities defined in ISO 9236-1 .16

62494-1 © IEC:2008 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –
EXPOSURE INDEX OF DIGITAL X-RAY IMAGING SYSTEMS –

Part 1: Definitions and requirements for general radiography

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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 62494-1 has been prepared by subcommittee 62B: Diagnostic
imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice.
The text of this standard is based on the following documents:
Enquiry draft Report on voting
62B/680/CDV 62B/703/RVC
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.

– 4 – 62494-1 © IEC:2008
In this standard, the following print types are used:
– requirements, compliance with which can be tested, and definitions: in roman type;
– explanations, advice, notes, general statements, exceptions and references: in smaller type;
– TERMS DEFINED IN CLAUSE 3 OF THIS STANDARD, IN IEC 60601-1 OR IN IEC 60788, AS
REFERENCED IN THE INDEX OF DEFINED TERMS: SMALL CAPITALS.
A list of all parts of the IEC 62494 series, published under the general title Medical electrical
equipment – Exposure index of digital X-ray imaging systems, can be found on the IEC
website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
62494-1 © IEC:2008 – 5 –
INTRODUCTION
The direct connection between the level of detector exposure and optical density is well
established in film-screen radiology. This is not the case in digital radiography, where almost
always a constant image characteristic is achieved using automatic image processing.
Consequen
...