SIST EN 61676:2003
(Main)Medical electrical equipment - Dosimetric instruments used for non-invasive measurement of X-ray tube voltage in diagnostic radiology
Medical electrical equipment - Dosimetric instruments used for non-invasive measurement of X-ray tube voltage in diagnostic radiology
Specifies the performance requirements of instruments as used in the non-invasive measurement of X-ray tube voltage up to 150 kV and the relevant compliance tests. Describes the method for calibration and gives guidance for estimating the uncertainty in measurements performed under conditions different from those during calibration. This standard is not concerned with the safety aspect of such instruments. The requirements for electrical safety applying to them are contained in EN 60601-1.
Medizinische elektrische Geräte - Geräte für die nicht-invasive Messung der Röntgenröhrenspannung in der diagnostischen Radiologie
Appareils électromédicaux - Instruments de dosimétrie pour la mesure non invasive de la tension du tube radiogène dans la radiologie de diagnostic
Medicinska električna oprema - Dozimetrijska oprema za posredno merjenje napetosti rentgenske elektronke v diagnostični radiologiji
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61676:2003
01-april-2003
0HGLFLQVNDHOHNWULþQDRSUHPD'R]LPHWULMVNDRSUHPD]DSRVUHGQRPHUMHQMH
QDSHWRVWLUHQWJHQVNHHOHNWURQNHYGLDJQRVWLþQLUDGLRORJLML
Medical electrical equipment - Dosimetric instruments used for non-invasive
measurement of X-ray tube voltage in diagnostic radiology
Medizinische elektrische Geräte - Geräte für die nicht-invasive Messung der
Röntgenröhrenspannung in der diagnostischen Radiologie
Appareils électromédicaux - Instruments de dosimétrie pour la mesure non invasive de la
tension du tube radiogène dans la radiologie de diagnostic
Ta slovenski standard je istoveten z: EN 61676:2002
ICS:
11.040.50 Radiografska oprema Radiographic equipment
17.240 Merjenje sevanja Radiation measurements
SIST EN 61676:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD EN 61676
NORME EUROPÉENNE
EUROPÄISCHE NORM December 2002
ICS 11.040.50; 11.040.55
English version
Medical electrical equipment -
Dosimetric instruments used for non-invasive measurement
of X-ray tube voltage in diagnostic radiology
(IEC 61676:2002)
Appareils électromédicaux - Medizinische elektrische Geräte –
Instruments de dosimétrie pour la mesure Geräte für die nicht-invasive Messung
non invasive de la tension du tube radiogène der Röntgenröhrenspannung
dans la radiologie de diagnostic in der diagnostischen Radiologie
(CEI 61676:2002) (IEC 61676:2002)
This European Standard was approved by CENELEC on 2002-11-01. 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, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and 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
© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61676:2002 E
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EN 61676:2002 - 2 -
Foreword
The text of document 62C/340/FDIS, future edition 1 of IEC 61676, prepared by SC 62C, Equipment for
radiotherapy, nuclear medicine and radiation dosimetry, of IEC TC 62, Electrical equipment in medical
practice, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 61676 on 2002-11-01.
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) 2003-08-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2005-11-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annex ZA is normative and annexes A, B and C are informative.
Annex ZA has been added by CENELEC.
In this standard, the following print types are used:
– requirements, compliance with which can be tested, and definitions: roman type;
– notes, explanations, advice, general statements and exceptions: smaller roman type;
– test specifications: italic type;
– TERMS USED THROUGHOUT THIS STANDARD THAT HAVE BEEN DEFINED IN CLAUSE 3 OR IN EN 60601-1:
SMALL CAPITALS.
__________
Endorsement notice
The text of the International Standard IEC 61676:2002 was approved by CENELEC as a European
Standard without any modification.
__________
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- 3 - EN 61676:2002
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
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 60417 Series Graphical symbols for use on equipment EN 60417 Series
IEC 60788 1984 Medical radiology - Terminology - -
IEC 61000-4-2 1995 Electromagnetic compatibility (EMC) EN 61000-4-2 1995
Part 4-2: Testing and measurement
techniques - Electrostatic discharge
immunity test
IEC 61000-4-3 2002 Part 4-3: Testing and measurement EN 61000-4-3 2002
techniques - Radiated, radio-frequency,
electromagnetic field immunity test
IEC 61000-4-4 1995 Part 4-4: Testing and measurement EN 61000-4-4 1995
techniques - Electrical fast
transient/burst immunity test
IEC 61000-4-5 1995 Part 4-5: Testing and measurement EN 61000-4-5 1995
techniques - Surge immunity test
IEC 61000-4-6 1996 Part 4-6: Testing and measurement EN 61000-4-6 1996
techniques - Immunity to conducted
disturbances, induced by radio-
frequency fields
IEC 61000-4-11 1994 Part 4-11: Testing and measurement EN 61000-4-11 1994
techniques - Voltage dips, short
interruptions and voltage variations
immunity tests
IEC 61010-1 2001 Safety requirements for electrical EN 61010-1 2001
equipment for measurement, control, + corr. June 2002
and laboratory use
Part 1: General requirements
IEC 61187 (mod) 1993 Electrical and electronic measuring EN 61187 1994
equipment - Documentation + corr. March 1995
---------------------- Page: 4 ----------------------
EN 61676:2002 - 4 -
Publication Year Title EN/HD Year
ISO 1993 International vocabulary of basic and - -
general terms in metrology
ISO 7000 1989 Graphical symbols for use on - -
equipment - Index and synopsis
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INTERNATIONAL IEC
STANDARD
61676
First edition
2002-09
Medical electrical equipment –
Dosimetric instruments used for
non-invasive measurement of X-ray
tube voltage in diagnostic radiology
Appareils électromédicaux –
Instruments de dosimétrie pour la mesure
non invasive de la tension du tube radiogène
dans la radiologie de diagnostic
IEC 2002 Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale
V
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue
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– 2 – 61676 IEC:2002(E)
CONTENTS
FOREWORD . 3
INTRODUCTION .5
1 Scope and object . 6
2 Normative references. 6
3 Terminology and definitions . 7
4 General performance requirements for measurement of PRACTICAL PEAK VOLTAGE
measurements .10
4.1 Quantity to be measured.10
4.2 Limits of PERFORMANCE CHARACTERISTICs .10
4.3 LIMITS OF VARIATION for effects of INFLUENCE QUANTITIES .13
4.4 Performance test procedures.15
5 Special instrumental requirements and marking .21
5.1 Requirements for the complete instruments .21
5.2 General .21
5.3 Display .22
5.4 Range of measurement.22
5.5 Connectors and cables .22
6ACCOMPANYING DOCUMENTS .22
6.1 General .22
6.2 Information provided.22
6.3 Instrument description .22
6.4 Detector.22
6.5 Delay time .22
6.6 Measurement window .22
6.7 Data outlet.23
6.8 Transport and storage .23
Annex A (informative) Recommended performance criteria for the invasive divider .24
Annex B (informative) Additional information on PRACTICAL PEAK VOLTAGE .25
Annex C (informative) Glossary of defined terms.32
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61676 IEC:2002(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
MEDICAL ELECTRICAL EQUIPMENT –
Dosimetric instruments used for non-invasive measurement
of X-ray tube voltage in diagnostic radiology
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61676 has been prepared by subcommittee SC 62C: Equipment
for radiotherapy, nuclear medicine and radiation dosimetry, of IEC Technical Committee 62:
Electrical equipment in medical practice.
The text of this standard is based on the following documents:
FDIS Report on voting
62C/340/FDIS 62C/344/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 3.
Annexes A, B and C are for information only.
In this standard the following print types are used:
− requirements, compliance with which can be tested, and definitions: in roman type;
− notes, explanations, advice, general statements and exceptions: in small roman type;
− test specifications: in italic type;
− TERMS USED THROUGHOUT THIS STANDARD THAT HAVE BEEN DEFINED IN CLAUSE 3 OR IN IEC
60601-1 AND ITS COLLATERAL STANDARDS: IN SMALL CAPITALS.
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– 4 – 61676 IEC:2002(E)
The committee has decided that the contents of this publication will remain unchanged until
2004. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
NOTE The committee is aware of the fact that this standard does not address all problems associated with non-
invasive high voltage measurements. In particular one influence quantity concerning the target condition is not
dealt with at all. Before this can be done, a substantial amount of measurements is still necessary to improve the
physical understanding of this influence quantity. On the other hand, for the reasons described in the introduction
there is an urgent need to publish this standard in order to assure that non-invasive measurements are comparable
to each other within tolerable uncertainties, regardless of differences in X-RAY GENERATOR, waveform or other
influence quantities (except target condition), which is not the case for the time being. The committee has decided
to revise this standard as soon as sufficient knowledge on the outstanding items is available.
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61676 IEC:2002(E) – 5 –
INTRODUCTION
The result of a measurement of the X-RAY TUBE VOLTAGE by means of invasive or non-invasive
instruments is normally expressed in the form of one single number for the value of the tube
voltage, irrespective of whether the tube voltage is constant potential or shows a time
dependent waveform. Non-invasive instruments for the measurement of the X-RAY TUBE
VOLTAGE on the market usually indicate the ‘mean peak voltage’. But the quantity ‘mean peak
voltage’ is not unambiguously defined and may be any mean of all voltage peaks. It is
impossible to establish test procedures for the performance requirements of non-invasive
instruments for the measurement of the X-RAY TUBE VOLTAGE without the definition of the
quantity under consideration. Therefore, this Standard is based on a quantity recently
1
proposed in the literature to be called "PRACTICAL PEAK VOLTAGE". The PRACTICAL PEAK
VOLTAGE is unambiguously defined and applicable to any waveform. This quantity is related to
the spectral distribution of the emitted X-RADIATION and the image properties. X-RAY
GENERATORS operating at the same value of the PRACTICAL PEAK VOLTAGE will produce the
same low level contrast in the RADIOGRAMS, even when the waveforms of the tube voltages
are different. Detailed information on this concept is provided in Annex B. An example for the
calculation of the PRACTICAL PEAK VOLTAGE in the case of a “falling load” waveform is also
given in Annex B.
As a result of introducing a new quantity, the problem arises that this standard has been
written for instruments which were not explicitly designed for the measurement of the
PRACTICAL PEAK VOLTAGE. However, from preliminary results of a trial type test of a non-
invasive instrument currently on the market, it can be expected that future instruments and
most instruments on the market will be able to fulfil the requirements stated in this standard
without insurmountable difficulties. For the most critical requirements on voltage waveform
and frequency dependence of the RESPONSE, it turned out from these investigations that it is
even easier to comply with the standard by using the PRACTICAL PEAK VOLTAGE as the
measurement quantity.
The calibration and adjustment of the X-RAY TUBE VOLTAGE of an X-RAY GENERATOR is generally
performed by the MANUFACTURER using a direct INVASIVE MEASUREMENT. Instruments utilising
NON-INVASIVE MEASUREMENTS can also be used to check the calibration or to adjust THE X-RAY
TUBE VOLTAGE. These instruments are required to have uncertainties of the voltage
measurement comparable with the INVASIVE MEASUREMENT. One of the most important
parameters of diagnostic X-RAY EQUIPMENT is the voltage applied to the X-RAY TUBE, because
both the image quality in diagnostic radiology and the DOSE received by the PATIENT
undergoing radiological examinations are dependent on the X-RAY TUBE VOLTAGE. An overall
uncertainty below ±5 % is required, and this value serves as a guide for the LIMITS OF
VARIATION for the effects of INFLUENCE QUANTITIES.
———————
1
See annex B.
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– 6 – 61676 IEC:2002(E)
MEDICAL ELECTRICAL EQUIPMENT –
Dosimetric instruments used for non-invasive measurement
of X-ray tube voltage in diagnostic radiology
1 Scope and object
This International Standard specifies the performance requirements of instruments as used in
the NON-INVASIVE MEASUREMENT of X-RAY TUBE VOLTAGE up to 150 kV and the relevant
compliance tests. This standard also describes the method for calibration and gives guidance
for estimating the uncertainty in measurements performed under conditions different from
those during calibration.
Applications for such measurement are found in diagnostic RADIOLOGY including
mammography, COMPUTED TOMOGRAPHY (CT), dental radiology and RADIOSCOPY. This standard
is not concerned with the safety aspect of such instruments. The requirements for electrical
safety applying to them are contained in IEC 61010-1.
2 Normative references
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.
IEC 60417 (all parts), Graphical symbols for use on equipment
IEC 60788:1984, Medical radiology – Terminology
IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 2: Electrostatic discharge immunity test. Basic EMC Publication
IEC 61000-4-3:2000, Electromagnetic compatibility (EMC) – Part 4-3: Testing and measure-
ment techniques – Radiated, radio-frequency, electromagnetic field immunity test. Basic EMC
Publication
IEC 61000-4-4:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 4: Electrical fast transient/burst immunity test. Basic EMC Publication
IEC 61000-4-5:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 5: Surge immunity test. Basic EMC Publication
IEC 61000-4-6:1996, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 6: Immunity to conducted disturbances, induced by radio frequency
fields. Basic EMC Publication
IEC 61000-4-11:1994, Electromagnetic compatibility (EMC) – Part 4: Testing and measure-
ment techniques – Section 11: Voltage dips, short interruptions and voltage variations
immunity tests. Basic EMC Publication
IEC 61010-1:2001, Safety requirements for electrical equipment for measurement, control,
and laboratory use – Part 1:General Requirements
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61676 IEC:2002(E) – 7 –
IEC 61187:1993, Electrical and electronic measuring equipment – Documentation
ISO:1993, International vocabulary of basic and general terms in metrology
(ISBN 92-67-01075-1)
ISO 7000:1989, Graphical symbols for use on equipment – Index and synopsis
3 Terminology and definitions
For the purposes of this standard the following definitions apply.
The definitions given in this standard are generally in agreement with those in IEC 60788 and
the ISO International vocabulary of basic and general terms in metrology. Any terms not
defined in this subclause have the meanings defined in the above publications or are
assumed to be in general scientific usage.
3.1
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
3.2
EFFECTIVE RANGE
range of INDICATED VALUES for which an instrument complies with a stated performance. The
maximum (minimum) effective INDICATED VALUE is the highest (lowest) in this range
3.3
INDICATED VALUE
the value of quantity derived from the scale reading of an instrument together with any scale
factors indicated on the control panel of the instrument
3.4
INFLUENCE QUANTITY
any external quantity that may affect the performance of an instrument (e.g. ambient
temperature etc.) and any property of the X-RAY EQUIPMENT under test that needs to be taken
into account in using the instrument for NON-INVASIVE MEASUREMENT of X-RAY TUBE VOLTAGE
(e.g. range of X-RAY TUBE VOLTAGE, ANODE ANGLE, anode material, TOTAL FILTRATION etc.)
3.5
INSTRUMENT PARAMETER
any internal property of an instrument that may affect the performance of the instrument
3.6
INTRINSIC ERROR
deviation of the MEASURED VALUE (i.e. the INDICATED VALUE, corrected to REFERENCE
CONDITIONS) from the CONVENTIONAL TRUE VALUE under STANDARD TEST CONDITIONS
3.7
INVASIVE MEASUREMENT
measurement of the X-RAY TUBE VOLTAGE by external connection of a suitable meter or a high
resistance divider
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– 8 – 61676 IEC:2002(E)
3.8
LIMITS OF VARIATION
the maximum VARIATION of a PERFORMANCE CHARACTERISTIC y, permitted by this standard. If
the LIMITS OF VARIATION are stated as ±L % the VARIATION Δy / y, expressed as a percentage,
shall remain in the range from −L % to +L %
3.9
MAXIMUM PEAK VOLTAGE
maximum value of the X-RAY TUBE VOLTAGE in a specified time interval. The unit of this
quantity is the volt (V)
3.10
MEAN PEAK VOLTAGE
mean value of all X-RAY TUBE VOLTAGE peaks during a specified time interval. The unit of this
quantity is the volt (V)
3.11
MEASURED VALUE
the best estimate of the CONVENTIONAL TRUE VALUE of a quantity, being derived from the
INDICATED VALUE of an instrument together with the application of all relevant CORRECTION
FACTORS
NOTE The CONVENTIONAL TRUE VALUE will usually be the value determined by the working standard with which the
instrument under test is being compared
3.12
MINIMUM EFFECTIVE RANGE
the MINIMUM EFFECTIVE RANGE is the smallest permitted range of INDICATED VALUES for which an
instrument complies with a stated performance
3.13
NON-INVASIVE MEASUREMENT
measurement of X-RAY TUBE VOLTAGE by analysis of the emitted RADIATION
3.14
PERFORMANCE CHARACTERISTIC
one of the quantities used to define the performance of an instrument (e.g. RESPONSE)
3.15
VOLTAGE RIPPLE
the VOLTAGE RIPPLE at the X-RAY TUBE, r, is expressed as a percentage of the peak voltage,
U , over a specified time interval. This is expressed by the equation:
max
U − U
max min
r = ⋅ 100 %
U
max
where U is the highest voltage in the interval, and U is the lowest voltage in the interval
max min
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61676 IEC:2002(E) – 9 –
3.16
PRACTICAL PEAK VOLTAGE (PPV)
ˆ
The PRACTICAL PEAK VOLTAGE U is defined as:
U
max
p(U) ⋅ w(U) ⋅ U dU
∫
U
max
U
ˆ min
U = with p(U) dU = 1
∫
U
max
U
min
p(U) ⋅ w(U) dU
∫
U
min
where p(U) is the distribution function for the voltage U and w(U) is a weighting function. U
max
is the highest voltage in the interval, and U is the lowest voltage in the interval. The unit of
min
the quantity PRACTICAL PEAK VOLTAGE is the volt (V)
NOTE Additional information on the PRACTICAL PEAK VOLTAGE, the weighting function w(U) and the distribution
function p(U) is provided in Annex B. Using this weighting function w(U) the PRACTICAL PEAK VOLTAGE will be
defined as the constant potential which produces the same AIR KERMA contrast behind a specified PHANTOM as the
non-dc voltage under test.
3.17
RATED RANGE (of use)
the range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER within which the
instrument will operate within the LIMITS OF VARIATION. Its limits are the maximum and
minimum RATED values.
The MINIMUM RATED RANGE is the least range of an INFLUENCE QUANTITY or INSTRUMENT
PARAMETER within which the instrument shall operate within the specified LIMITS OF VARIATION
in order to comply with this standard
3.18
REFERENCE CONDITIONS
conditions under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
REFERENCE VALUES
3.19
REFERENCE VALUE
particular value of an INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) chosen for the
purposes of reference 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
3.20
RELATIVE INTRINSIC ERROR
the ratio of the INTRINSIC ERROR to the CONVENTIONAL TRUE VALUE
3.21
RESPONSE
the quotient of the INDICATED VALUE divided by the CONVENTIONAL TRUE VALUE
3.22
STANDARD TEST CONDITIONS
conditions under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
STANDARD TEST VALUES
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– 10 – 61676 IEC:2002(E)
3.23
STANDARD TEST VALUES
a value, values, or a range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER,
which is/are permitted when carrying out calibrations or tests on another INFLUENCE QUANTITY
or INSTRUMENT PARAMETER
3.24
VARIATION
The 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)
3.25
X-RAY TUBE VOLTAGE
potential difference applied to an X-RAY TUBE between the anode and the cathode . The unit of
this quantity is the volt (V)
4 General performance requirements for measurement of PRACTICAL PEAK
VOLTAGE measurements
4.1 Quantity to be measured
The quantity to be measured is the PRACTICAL PEAK VOLTAGE.
NOTE Additional quantities may be displayed.
The MINIMUM EFFECTIVE RANGES of PRACTICAL PEAK VOLTAGE shall be as listed in table 1 for the
relevant X-RAY applications.
Table 1 – MINIMUM EFFECTIVE RANGES
Application Nominal Anode Material MINIMUM EFFECTIVE RANGE
Mammography
a)
24 kV to 35 kV
Mo
(20 kV to 50 kV)
Diagnostic
W 60 kV to 120 kV
(40 kV to 150 kV)
CT
W 100 kV to 140 kV
(80 kV to 150 kV)
Dental
W 60 kV to 90 kV
(40 kV to 110 kV)
Fluoroscopic
W 60 kV to 120 kV
(40 kV to 130 kV)
a)
For mammography anode materials other than Mo, the MINIMUM EFFECTIVE RANGE of PPV shall be at least
10 kV.
4.2 Limits of PERFORMANCE CHARACTERISTICs
4.2.1 Limits
All values of the limits of PERFORMANCE CHARACTERISTICS stated in this subclause do not
contain the uncertainty of the test equipment.
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61676 IEC:2002(E) – 11 –
4.2.2 Maximum error
4.2.2.1 Maximum RELATIVE INTRINSIC ERROR for voltages above 50 kV
ˆ
The RELATIVE INTRINSIC ERROR, l, of PRACTICAL PEAK VOLTAGE, U , measurements made under
STANDARD TEST CONDITIONS, shall not be greater than ±2 % over the EFFECTIVE RANGE of
voltages. This is expressed by the equation:
ˆ ˆ
U − U
meas true
I = ≤ 0,02
ˆ
U
true
ˆ ˆ
where U is the MEASU
...
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