SIST EN 61674:2013

SLOVENSKI STANDARD
01-junij-2013
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Medical electrical equipment - Dosimeters with ionization chambers and/or semi-
conductor detectors as used in X-ray diagnostic imaging
Appareils électromédicaux - Dosimètres à chambres d'ionisation et/ou à détecteurs à
semi-conducteurs utilisés en imagerie de diagnostic à rayonnement X
Ta slovenski standard je istoveten z: EN 61674:2013
ICS:
11.040.50 Radiografska oprema Radiographic equipment
17.240 Merjenje sevanja Radiation measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 61674
NORME EUROPÉENNE
February 2013
EUROPÄISCHE NORM
ICS 11.040.50 Supersedes EN 61674:1997 + A1:2002

English version
Medical electrical equipment -
Dosimeters with ionization chambers and/or semiconductor detectors as
used in X-ray diagnostic imaging
(IEC 61674:2012)
Appareils électromédicaux -  Medizinische elektrische Geräte -
Dosimètres à chambres d'ionisation et/ou Dosimeter mit Ionisationskammern
à détecteurs à semi-conducteurs utilisés und/oder Halbleiterdetektoren für den
en imagerie de diagnostic Einsatz an diagnostischen
à rayonnement X Röntgeneinrichtungen
(CEI 61674:2012) (IEC 61674:2012)

This European Standard was approved by CENELEC on 2013-01-03. 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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management Centre has the same status as the official versions.

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

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

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61674:2013 E
Foreword
The text of document 62C/551/FDIS, future edition 2 of IEC 61674, prepared by IEC TC 62 "Electrical
equipment in medical practice" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 61674:2013.
The following dates are fixed:
(dop) 2013-10-03
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2016-01-03
standards conflicting with the

document have to be withdrawn
This document supersedes EN 61674:1997 + A1:2002.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
In this standard, the following print types are used:
– Requirements and definitions: roman type.
– Test specifications: italic type.
– Informative material appearing outside of tables, such as notes, examples and references: in smaller type.
Normative text of tables is also in a smaller type.
– TERMS DEFINED IN CLAUSE 3 OF EN 60601-1, IN THIS PARTICULAR STANDARD OR AS NOTED: SMALL
CAPITALS.
The verbal forms used in this standard conform to usage described in Annex H of the ISO/IEC Directives,
Part 2. For the purposes of this standard, the auxiliary verb:
– “shall” means that compliance with a requirement or a test is mandatory for compliance with this
standard;
– “should” means that compliance with a requirement or a test is recommended but is not mandatory for
compliance with this standard;
– “may” is used to describe a permissible way to achieve compliance with a requirement or test.

Endorsement notice
The text of the International Standard IEC 61674:2012 was approved by CENELEC as a European
Standard without any modification.

- 3 - EN 61674:2013
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
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 60050 Series International Electrotechnical Vocabulary - -

IEC 60417 Data- Graphical symbols for use on equipment - -
base
IEC 60601-1 2005 Medical electrical equipment - EN 60601-1 2006
+ corr. December 2006 Part 1: General requirements for basic safety + corr. March 2010
+ corr. December 2007 and essential performance + A11 2011

IEC 60601-1-3 2008 Medical electrical equipment - EN 60601-1-3 2008
Part 1-3: General requirements for basic + corr. March 2010
safety and essential performance - Collateral
Standard: Radiation protection in diagnostic
X-ray equipment
IEC 60731 2011 Medical electrical equipment - Dosimeters EN 60731 2012
with ionization chambers as used in
radiotherapy
IEC/TR 60788 2004 Medical electrical equipment - Glossary of - -
defined terms
IEC 61000-4 Series Electromagnetic compatibility (EMC) - EN 61000-4 Series
Part 4: Testing and measurement techniques

IEC 61000-4-2 - Electromagnetic compatibility (EMC) - EN 61000-4-2 -
Part 4-2: Testing and measurement
techniques - Electrostatic discharge immunity
test
IEC 61000-4-3 - Electromagnetic compatibility (EMC) - EN 61000-4-3 -
Part 4-3: Testing and measurement
techniques - Radiated, radio-frequency,
electromagnetic field immunity test

IEC 61000-4-4 - Electromagnetic compatibility (EMC) - EN 61000-4-4 -
Part 4-4: Testing and measurement
techniques - Electrical fast transient/burst
immunity test
IEC 61000-4-6 - Electromagnetic compatibility (EMC) - EN 61000-4-6 -
Part 4-6: Testing and measurement
techniques - Immunity to conducted
disturbances, induced by radio-frequency
fields
IEC 61000-4-11 - Electromagnetic compatibility (EMC) - EN 61000-4-11 -
Part 4-11: Testing and measurement
techniques - Voltage dips, short interruptions
and voltage variations immunity tests

IEC 61187 - Electrical and electronic measuring EN 61187 -
equipment - Documentation
IEC 61267 2005 Medical diagnostic X-ray equipment - EN 61267 2006
Radiation conditions for use in the
determination of characteristics

ISO/IEC Guide 98-3 2008 Uncertainty of measurement - - -
Part 3: Guide to the expression of uncertainty
in measurement (GUM:1995)
ISO/IEC Guide 99 2007 International vocabulary of metrology - Basic - -
and general concepts and associated terms
(VIM)
ISO 3534-1 2006 Statistics - Vocabulary and symbols - - -
Part 1: General statistical terms and terms
used in probability
IEC 61674 ®
Edition 2.0 2012-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment – Dosimeters with ionization chambers and/or

semiconductor detectors as used in X-ray diagnostic imaging

Appareils électromédicaux – Dosimètres à chambres d’ionisation et/ou à

détecteurs à semi-conducteurs utilisés en imagerie de diagnostic à

rayonnement X
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX W
ICS 11.040.50 ISBN 978-2-83220-510-5

– 2 – 61674 © IEC:2012
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope and object . 7
1.1 Scope . 7
1.2 Object . 7
2 Normative references . 7
3 Terms and definitions . 8
4 General requirements . 15
4.1 Performance requirements . 15
4.2 REFERENCE VALUES and STANDARD TEST VALUES . 15
4.3 General test conditions . 16
4.3.1 STANDARD TEST CONDITIONS . 16
4.3.2 Statistical fluctuations . 17
4.3.3 STABILIZATION TIME . 17
4.3.4 Adjustments during test . 17
4.3.5 Batteries . 17
4.4 Constructional requirements as related to performance . 18
4.4.1 Components . 18
4.4.2 Display . 18
4.4.3 Indication of battery condition . 18
4.4.4 Indication of polarizing voltage failure . 18
4.4.5 Over-ranging . 18
4.4.6 MEASURING ASSEMBLIES with multiple DETECTOR ASSEMBLIES . 19
4.4.7 Radioactive STABILITY CHECK DEVICE . 19
4.5 UNCERTAINTY of measurement . 20
5 Limits of PERFORMANCE CHARACTERISTICS . 20
5.1 Linearity . 20
5.2 Repeatability . 20
5.2.1 General . 20
5.2.2 Repeatability in the ATTENUATED BEAM . 20
5.2.3 Repeatability in the UNATTENUATED BEAM . 21
5.3 RESOLUTION of reading . 21
5.4 STABILIZATION TIME . 21
5.5 Effect of pulsed radiation on AIR KERMA and AIR KERMA LENGTH PRODUCT
measurements . 22
5.6 Reset on AIR KERMA and AIR KERMA LENGTH PRODUCT ranges . 22
5.7 Effects of LEAKAGE CURRENT . 22
5.7.1 AIR KERMA RATE measurements . 22
5.7.2 AIR KERMA and AIR KERMA LENGTH PRODUCT measurements . 22
5.8 Stability . 23
5.8.1 Long term stability . 23
5.8.2 Accumulated dose stability . 23
5.9 Measurements with a radioactive STABILITY CHECK DEVICE . 23
6 LIMITS OF VARIATION for effects of INFLUENCE QUANTITIES . 24
6.1 General . 24
6.2 Energy dependence of RESPONSE . 24

61674 © IEC:2012 – 3 –
6.3 AIR KERMA RATE dependence of AIR KERMA and AIR KERMA LENGTH PRODUCT
measurements . 25
6.3.1 MEASURING ASSEMBLY . 25
6.3.2 IONIZATION CHAMBER – Recombination losses . 26
6.4 Dependence of DETECTOR RESPONSE on angle of incidence of radiation . 26
6.4.1 Non-CT detectors . 26
6.4.2 CT DETECTORS . 26
6.5 Operating voltage . 27
6.5.1 Mains-operated DOSIMETERS . 27
6.5.2 Battery-operated DOSIMETERS . 27
6.5.3 Mains rechargeable, battery-operated DOSIMETERS . 27
6.6 Air pressure . 28
6.7 Air pressure EQUILIBRATION TIME of the RADIATION DETECTOR . 28
6.8 Temperature and humidity . 28
6.9 Electromagnetic compatibility . 29
6.9.1 ELECTROSTATIC DISCHARGE . 29
6.9.2 Radiated electromagnetic fields . 29
6.9.3 CONDUCTED DISTURBANCES induced by bursts and radio frequencies . 30
6.9.4 Voltage dips, short interruptions and voltage VARIATIONS . 30
6.10 Field size . 30
6.11 EFFECTIVE LENGTH and spatial uniformity of RESPONSE of CT DOSIMETERS . 30
7 Marking . 31
7.1 DETECTOR ASSEMBLY . 31
7.2 MEASURING ASSEMBLY . 31
7.3 Radioactive STABILITY CHECK DEVICE . 31
8 ACCOMPANYING DOCUMENTS . 31
Annex A (informative) COMBINED STANDARD UNCERTAINTY for dosimeter performance . 33
Index of defined terms . 34

Table 1 – REFERENCE and STANDARD TEST CONDITIONS . 16
Table 2 – Number of readings required to detect true differences ∆ (95 % confidence
level) between two sets of instrument readings . 17
Table 3 – Maximum values for the COEFFICIENT OF VARIATION, v , for measurements
max
in the attenuated beam . 21
Table 4 – Maximum values for the COEFFICIENT OF VARIATION, v , for measurements
max
in the unattenuated beam . 21
Table 5 – LIMITS OF VARIATION for the effects of INFLUENCE QUANTITIES . 24
Table 6 – Climatic conditions . 28
Table A.1 – Estimation of COMBINED STANDARD UNCERTAINTY for dosimeter performance . 33

– 4 – 61674 © IEC:2012
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –
DOSIMETERS WITH IONIZATION CHAMBERS AND/OR
SEMICONDUCTOR DETECTORS AS USED
IN X-RAY DIAGNOSTIC 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 61674 has been prepared by subcommittee 62C: Equipment for
radiotherapy, nuclear medicine and radiation dosimetry, of IEC technical committee 62:
Electrical equipment in medical practice.
This second edition cancels and replaces the first edition of IEC 61674. This edition
constitutes a technical revision.
The text of this standard is based on the following documents:
FDIS Report on voting
62C/551/FDIS 62C/555/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.

61674 © IEC:2012 – 5 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
In this standard, the following print types are used:
– Requirements and definitions: roman type.
– Test specifications: italic type.
– Informative material appearing outside of tables, such as notes, examples and references: in smaller type.
Normative text of tables is also in a smaller type.
– TERMS DEFINED IN CLAUSE 3 OF IEC 60601-1, IN THIS PARTICULAR STANDARD OR AS NOTED:
SMALL CAPITALS.
The verbal forms used in this standard conform to usage described in Annex H of the ISO/IEC
Directives, Part 2. For the purposes of this standard, the auxiliary verb:
– “shall” means that compliance with a requirement or a test is mandatory for compliance
with this standard;
– “should” means that compliance with a requirement or a test is recommended but is not
mandatory for compliance with this standard;
– “may” is used to describe a permissible way to achieve compliance with a requirement or
test.
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 – 61674 © IEC:2012
INTRODUCTION
Diagnostic radiology is the largest contributor to man-made IONIZING RADIATION to which the
public is exposed. The reduction in the exposure received by PATIENTS undergoing medical
radiological examinations or procedures has therefore become a central issue in recent years.
The PATIENT dose will be minimized when the X-ray producing equipment is correctly adjusted
for image quality and radiation output. These adjustments require that the routine
measurement of AIR KERMA, AIR KERMA LENGTH PRODUCT and/or AIR KERMA RATE be made
accurately. The equipment covered by this standard plays an essential part in achieving the
required accuracy. The DOSIMETERS used for adjustment and control measurements must be
of satisfactory quality and must therefore fulfil the special requirements laid down in this
standard.
61674 © IEC:2012 – 7 –
MEDICAL ELECTRICAL EQUIPMENT –
DOSIMETERS WITH IONIZATION CHAMBERS AND/OR
SEMICONDUCTOR DETECTORS AS USED
IN X-RAY DIAGNOSTIC IMAGING
1 Scope and object
1.1 Scope
This International Standard specifies the performance and some related constructional
requirements of DIAGNOSTIC DOSIMETERS intended for the measurement of AIR KERMA, AIR
KERMA LENGTH PRODUCT or AIR KERMA RATE, in photon radiation fields used in RADIOGRAPHY,
including mammography, RADIOSCOPY and COMPUTED TOMOGRAPHY (CT), for X-radiation with
generating potentials not greater than 150 kV.
This International Standard is applicable to the performance of DOSIMETERS with VENTED
IONIZATION CHAMBERS and/or SEMICONDUCTOR DETECTORS as used in X-ray diagnostic imaging.
1.2 Object
The object of this standard is:
a) to establish requirements for a satisfactory level of performance for DIAGNOSTIC
DOSIMETERS, and
b) to standardize the methods for the determination of compliance with this level of
performance.
This standard is not concerned with the safety aspects of DOSIMETERS. The DIAGNOSTIC
DOSIMETERS covered by this standard are not intended for use in the PATIENT ENVIRONMENT
and, therefore, the requirements for electrical safety applying to them are contained in
IEC 61010-1.
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 60050 (all parts), International Electrotechnical Vocabulary (available at
)
IEC 60601-1:2005, Medical electrical equipment – Part 1: General requirements for basic
safety and essential performance
IEC 60601-1-3:2008, Medical electrical equipment – Part 1-3: General requirements for basic
safety and essential performance – Collateral standard: Radiation protection in diagnostic
X-ray equipment
IEC 60417, Graphical symbols for use on equipment (Available at: symbols.info/equipment>
IEC 60731:2011, Medical electrical equipment – Dosimeters with ionization chambers as used
in radiotherapy
– 8 – 61674 © IEC:2012
IEC 60788:2004, Medical electrical equipment – Glossary of defined terms
IEC 61000-4 (all parts) Electromagnetic compatibility (EMC) – Part 4: Testing and measuring
techniques
IEC 61000-4-2, Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement
techniques – Electrostatic discharge immunity test
IEC 61000-4-3, Electromagnetic compatibility (EMC) – Part 4-3: Testing and measurement
techniques – Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4, Electromagnetic compatibility (EMC) – Part 4-4: Testing and measurement
techniques – Electrical fast transient/burst immunity test
IEC 61000-4-6, Electromagnetic compatibility (EMC) – Part 4-6: Testing and measurement
techniques – Immunity to conducted disturbances induced by radio-frequency fields
IEC 61000-4-11, Electromagnetic compatibility (EMC) – Part 4-11: Testing and measurement
techniques – Voltage dips, short interruptions and voltage variations immunity tests
IEC 61187, Electrical and electronic measuring equipment – Documentation
IEC 61267:2005, Medical diagnostic X-ray equipment – Radiation conditions for use in the
determination of characteristics
ISO/IEC GUIDE 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression of
uncertainty in measurement (GUM:1995)
ISO/IEC Guide 99:2007, International vocabulary of metrology – Basic and general concepts
and associated terms (VIM)
ISO 3534-1:2006, Statistics – Vocabulary and symbols – Part 1: General statistical terms and
terms used in probability
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC/TR 60788:2004 and
the following apply.
3.1
DIAGNOSTIC DOSIMETER
DOSIMETER
equipment which uses IONIZATION CHAMBERS and/or SEMICONDUCTOR DETECTORS for the
AIR KERMA, AIR KERMA LENGTH PRODUCT and/or AIR KERMA RATE in the beam of
measurement of
an X-RAY EQUIPMENT used for diagnostic medical radiological examinations
Note 1 to entry: A DIAGNOSTIC DOSIMETER contains the following components:
– one or more DETECTOR ASSEMBLIES which may or may not be an integral part of the MEASURING ASSEMBLY;
– a MEASURING ASSEMBLY;
– one or more STABILITY CHECK DEVICES (optional).
3.1.1
DETECTOR ASSEMBLY
RADIATION DETECTOR and all other parts to which the RADIATION DETECTOR is permanently
attached, except the MEASURING ASSEMBLY

61674 © IEC:2012 – 9 –
Note 1 to entry: The DETECTOR ASSEMBLY normally includes:
– the RADIATION DETECTOR and the stem (or body) on which the RADIATION DETECTOR is permanently mounted (or
embedded);
– the electrical fitting and any permanently attached cable or pre-amplifier.
3.1.1.1
RADIATION DETECTOR
element which transduces AIR KERMA, AIR KERMA LENGTH PRODUCT or AIR KERMA RATE into a
measurable electrical signal
Note 1 to entry: A radiation detector may be either an ionization chamber or a semiconductor detector.
3.1.1.1.1
IONIZATION CHAMBER
CHAMBER
ionizing RADIATION DETECTOR consisting of a CHAMBER filled with air, in which an electric field
insufficient to produce gas multiplication is provided for the collection at the electrodes of
charges associated with the ions and the ELECTRONS produced in the measuring volume of the
detector by IONIZING RADIATION
Note 1 to entry: An IONIZATION CHAMBER can be sealed or vented.
Note 2 to entry: Vented IONIZATION CHAMBERS are constructed in such a way as to allow the air inside the
measuring volume to communicate freely with the atmosphere, so that corrections to the RESPONSE for changes in
air density need to be made.
Note 3 to entry: Sealed IONIZATION CHAMBERS are not suitable, because the necessary wall thickness of a sealed
CHAMBER may cause an unacceptable energy dependence of the RESPONSE and because the long term stability of
sealed CHAMBERS is not guaranteed.
[SOURCE: IEC 60731:2011, 3.1.1.1, modified – three new notes to entry have replaced the
two original notes.]
3.1.1.1.2
VENTED IONIZATION CHAMBER
IONIZATION CHAMBER constructed in such a way as to allow the air inside the measuring volume
to communicate freely with the atmosphere such that corrections to the RESPONSE for changes
in air density need to be made
[SOURCE: IEC 60731:2011, 3.1.1.1.3, modified – the term has been changed from "vented
chamber" to "VENTED IONIZATION CHAMBER". ]
3.1.1.1.3
SEMICONDUCTOR DETECTOR
semiconductor device that utilises the production and motion of electron-hole pairs in a
charge carrier depleted region of the semiconductor for the detection and measurement of
IONIZING RADIATION
Note 1 to entry: The production of electron-hole pairs is caused either
– directly by interaction of the IONIZING RADIATION with the semiconductor material, or
– indirectly by first converting the incident radiation energy to light in a scintillator material directly in front of and
optically coupled to a semiconductor photodiode, which then produces the electrical signal.
3.1.2
MEASURING ASSEMBLY
device to measure the charge (or current) from the RADIATION DETECTOR and convert it into a
form suitable for displaying the values of DOSE or KERMA or their corresponding rates
[SOURCE: IEC 60731:2011, 3.1.2. modified – the term IONIZATION CHAMBER in the original
definition has been replaced by the term RADIATION DETECTOR ]

– 10 – 61674 © IEC:2012
3.1.3
STABILITY CHECK DEVICE
device which enables the stability of RESPONSE of the MEASURING ASSEMBLY and/or CHAMBER
ASSEMBLY to be checked
Note 1 to entry: The STABILITY CHECK DEVICE may be a purely electrical device, or a radiation source, or it may
include both.
[SOURCE: IEC 60731:2011, 3.1.3]
3.1.4
CT DOSIMETER
DIAGNOSTIC DOSIMETER which uses long narrow IONIZATION CHAMBERS and/or SEMICONDUCTOR
DETECTORS for the measurement of AIR KERMA integrated along the length of the DETECTOR
when the DETECTOR is exposed to a cross-sectional X-ray scan of a computed tomograph
Note 1 to entry: A CT DOSIMETER contains the following components:
– one or more DETECTOR ASSEMBLIES;
– a MEASURING ASSEMBLY.
3.1.5
CT DETECTOR
RADIATION DETECTOR which is used for CT dosimetry
3.2
INDICATED VALUE
value of a quantity derived from the reading of an instrument together with any scale factors
indicated on the control panel of the instrument
[SOURCE: IEC 60731:2011, 3.2]
3.3
TRUE VALUE
value of the physical quantity to be measured by an instrument
[SOURCE: IEC 60731:2011, 3.3]
3.4
CONVENTIONAL TRUE VALUE
value used instead of the TRUE VALUE when calibrating or determining the performance of an
TRUE VALUE is unknown and unknowable
instrument, since in practice the
Note 1 to entry: The CONVENTIONAL TRUE VALUE will usually be the value determined by the WORKING STANDARD
with which the instrument under test is being compared.
[SOURCE: IEC 60731:2011, 3.4]
3.5
MEASURED VALUE
best estimate of the TRUE VALUE of a quantity, being derived from the INDICATED VALUE of an
instrument together with the application of all relevant CORRECTION FACTORS and the
CALIBRATION FACTOR
Note 1 to entry: The MEASURED VALUE is sometimes also referred to as result of a measurement
[SOURCE: IEC 60731:2011, 3.5, modified – a new note to entry has been added.]
3.5.1
ERROR OF MEASUREMENT
difference remaining between the MEASURED VALUE of a quantity and the TRUE VALUE of that
quantity
61674 © IEC:2012 – 11 –
[SOURCE: IEC 60731:2011, 3.5.1]
3.5.2
OVERALL UNCERTAINTY
UNCERTAINTY associated with the MEASURED VALUE
Note 1 to entry: I.e. it represents the bounds within which the ERROR OF MEASUREMENT is estimated to lie (see
also 4.5).
[SOURCE: IEC 60731:2011, 3.5.2]
3.5.3
EXPANDED UNCERTAINTY
quantity defining an interval about the result of a measurement that may be expected to
encompass a large fraction of the distribution of values that could reasonably be attributed to
the measurand
[SOURCE: ISO/IEC GUIDE 98-3:2008, 2.3.5, modified – the three notes in the original
definition have been deleted.]
3.6
CORRECTION FACTOR
dimensionless multiplier which corrects the INDICATED VALUE of an instrument from its value
when operated under particular conditions to its value when operated under stated REFERENCE
CONDITIONS
[SOURCE: IEC 60731:2011, 3.6]
3.7
INFLUENCE QUANTITY
any external quantity that may affect the performance of an instrument
[SOURCE: IEC 60731:2011, 3.7]
3.8
INSTRUMENT PARAMETER
any internal property of an instrument that may affect the performance of this instrument
[SOURCE: IEC 60731:2011, 3.8]
3.9
REFERENCE VALUE
particular value of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER chosen for the purposes
of reference
Note 1 to entry: I.e. the value of an influence quantity (or INSTRUMENT PARAMETER) at which the CORRECTION
FACTOR for dependence on that INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) is unity.
[SOURCE: IEC 60731:2011, 3.9]
3.9.1
REFERENCE CONDITIONS
conditions under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
REFERENCE VALUES
[SOURCE: IEC 60731:2011, 3.9.1]

– 12 – 61674 © IEC:2012
3.10
STANDARD TEST VALUES
value, values, or range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER, which
are permitted when carrying out calibrations or tests on another INFLUENCE QUANTITY or
INSTRUMENT PARAMETER
[SOURCE: IEC 60731:2011, 3.10]
3.10.1
STANDARD TEST CONDITIONS
conditions under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
STANDARD TEST VALUES
[SOURCE: IEC 60731:2011, 3.10.1]
3.11
PERFORMANCE CHARACTERISTIC
one of the quantities used to define the performance of an instrument
[SOURCE: IEC 60731:2011, 3.11]
3.11.1
RESPONSE
quotient of the INDICATED VALUE divided by
the CONVENTIONAL TRUE VALUE at the position of the REFERENCE POINT of the IONIZATION
CHAMBER
[SOURCE: IEC 60731:2011, 3.11.1, modified – only the first paragraph of the original
definition has been retained.]
3.11.2
RESOLUTION
smallest change of reading to which a numerical value can be assigned without
further interpolation
smallest fraction of a scale interval that can be determined by an observer
under specified conditions
smallest significant increment of the reading
[SOURCE: IEC 60731:2011, 3.11.2,]
3.11.3
EQUILIBRATION TIME
time taken for a reading to reach and remain within a specified deviation from its final steady
value after a sudden change in an INFLUENCE QUANTITY has been applied to the instrument
[SOURCE: IEC 60731:2011, 3.11.3,]
3.11.4
RESPONSE TIME
time taken for a reading to reach and remain within a specified deviation from its final steady
value after a sudden change in the quantity being measured
[SOURCE: IEC 60731:2011, 3.11.4,]

61674 © IEC:2012 – 13 –
3.11.5
STABILIZATION TIME
time taken for a stated PERFORMANCE CHARACTERISTIC to reach and remain within a specified
deviation from its final steady value after the MEASURING ASSEMBLY has been switched on and
the polarizing voltage has been applied to the IONIZATION CHAMBER
[SOURCE: IEC 60731:2011, 3.11.5]
3.11.6
CHAMBER ASSEMBLY LEAKAGE CURRENT
LEAKAGE CURRENT
any current in the signal path arising in the CHAMBER ASSEMBLY which is not produced by
ionization in the measuring volume
[SOURCE: IEC 60731:2011, 3.11.6]
3.12
variation
relative difference, Δy/y, between the values of a PERFORMANCE CHARACTERISTIC y, when one
INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) assumes successively two specified values,
the other INFLUENCE QUANTITIES (and INSTRUMENT PARAMETERS) being kept constant at the
STANDARD TEST VALUES (unless other values are specified)
[SOURCE: IEC 60731:2011, 3.12]
3.13
LIMITS OF VARIATION
maximum permitted VARIATION of a PERFORMANCE CHARACTERISTIC
Note 1 to entry: If LIMITS OF VARIATION are stated as ±L %, the VARIATION Δy/y, expressed as a percentage, shall
remain in the range from – L % to + L %.
[SOURCE: IEC 60731:2011, 3.13]
3.14
EFFECTIVE RANGE OF INDICATED VALUES
EFFECTIVE RANGE
range of INDICATED VALUES for which an instrument complies with a stated performance
Note 1 to entry: The maximum (minimum) effective INDICATED VALUE is the highest (lowest) in this range.
Note 2 to entry: The concept of EFFECTIVE RANGE may, for example, also be applied to readings and to related
quantities not directly indicated by the instrument e.g. input current.
[SOURCE: IEC 60731:2011, 3.14,]
3.15
RATED RANGE OF USE
RATED RANGE
range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER within which the
instrument will operate within the LIMITS OF VARIATION
Note 1 to entry: Its limits are the maximum and minimum RATED VALUES.
[SOURCE: IEC 60731:2011, 3.15]
3.15.1
MINIMUM RATED RANGE
least range of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER over which the instrument
shall operate within the specified LIMITS OF VARIATION
[SOURCE: IEC 60731:2011, 3.15.1]

– 14 – 61674 © IEC:2012
3.16
REFERENCE POINT OF A RADIATION DETECTOR
REFERENCE POINT
point of a RADIATION DETECTOR, which during the calibration of the detector, is brought to
coincidence with the point at which the CONVENTIONAL TRUE VALUE is specified
[SOURCE: IEC 60731:2011, 3.16, modified – the term IONIZATION CHAMBER has been replaced
by RADIATION DETECTOR in both the term and the definition.]
3.17
MEDICAL ELECTRICAL EQUIPMENT
ME EQUIPMENT
electrical equipment having an APPLIED PART or transferring energy to or from the PATIENT or
detecting such energy transfer to or from the PATIENT and which is:
a) provided with not more than one connection to a particular SUPPLY MAINS; and
b) intended by its MANUFACTURER to be used:
1) in the diagnosis, treatment, or monitoring of a PATIENT; or
2) for compensation or alleviation of disease, injury or disability
[SOURCE: IEC 60601-1:2005, 3.63, modified – the five notes of the original definition have
not been retained. ]
3.18
UNATTENUATED BEAM
X-ray beam incident on the PATIENT or PHANTOM
3.18.1
UNATTENUATED BEAM QUALITY
RADIATION QUALITY of the x-ray beam at the location of the entrance surface of the PATIENT or
the PHANTOM, determined when the latter are absent
3.19
ATTENUATED BEAM
X-ray beam exiting the PATIENT or PHANTOM
3.19.1
ATTENUATED BEAM QUALITY
RADIATION QUALITY of the X-ray beam exiting the PATIENT or PHANTOM
3.20
RATED LENGTH
length along the axis of the CT DETECTOR within which the DETECTOR performs to its
specification
3.20.1
EFFECTIVE LENGTH
length along the axis of the CT DETECTOR between the two points at which the RESPONSE has
fallen to 50 % of its value at its geometrical centre
3.21
AIR KERMA
K
quotient of dE by dm where dE is the sum of the initial kinetic energies of all the charged
tr tr
ionizing particles liberated by uncharged ionizing particles in air of mass dm
–1
Note 1 to entry: The unit of AIR KERMA is Gy (where 1 Gy = 1 J·kg ).
[SOURCE: IEC 60731:2011, 3.31]

61674 © IEC:2012 – 15 –
3.21.1
AIR KERMA RATE

K
quotient of dK by dt, where dK is the increment of AIR KERMA in the time interval dt
–1 –1 –1
Note 1 to entry: The unit of AIR KERMA RATE is Gy·s (Gy·min ; Gy·h ).
[SOURCE: IEC 60731:2011, 3.31.1]
3.21.2
AIR KERMA LENGTH PRODUCT
PKL
line integral of the AIR KERMA K over a length L.
P = K(z)dz
KL
∫
L
Note 1 to entry: The unit of AIR KERMA LENGTH PRODUCT is Gy·m (mGy·m).
3.22
X-RAY TUBE VOLTAGE
potential difference applied to an X-RAY TUBE between the ANODE and the CATHODE. Usually,
X-RAY TUBE VOLTAGE is expressed by its peak value in kilovolt (kV)
[SOURCE: IEC 60601-1-3:2008, 3.88]
3.23
COEFFICIENT OF VARIATION
CV
STANDARD DEVIATION divided by the MEAN
[SOURCE: ISO 3534-1:2006, 2.38, modified – the notes of the original definition have not
been retained.]
3.24
INSTRUCTIONS FOR USE
those parts of the ACCOMPANYING DOCUMENTS giving the necessary information for safe and
proper use and operation of the equipment
[SOURCE: IEC/TR 60788:2004, rm-82-02]
4 General requirements
4.1 Performance requirements
In Clauses 5 and 6 the performance requirements are stated for a complete DIAGNOSTIC
DOSIMETER including both the DETECTOR ASS
...