IEC 61676:2023

IEC 61676 ®
Edition 2.0 2023-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Medical electrical equipment – Dosimetric instruments used for non-invasive
measurement of X-ray tube voltage in diagnostic radiology

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IEC 61676 ®
Edition 2.0 2023-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Medical electrical equipment – Dosimetric instruments used for non-invasive
measurement of X-ray tube voltage in diagnostic radiology
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 11.040.50; 11.040.55 ISBN 978-2-8322-6703-5

– 2 – IEC 61676:2023 RLV © IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
1 Scope and object . 7
2 Normative references . 7
3 Terminology Terms and definitions . 8
4 General performance requirements for measurement of PRACTICAL PEAK VOLTAGE
measurements . 11
4.1 Quantity to be measured . 11
4.2 Limits of PERFORMANCE CHARACTERISTICS . 12
4.2.1 Limits . 12
4.2.2 Maximum error . 12
4.2.3 Over and under range indications . 13
4.2.4 Repeatability . 13
4.2.5 Long term stability . 13
4.3 LIMITS OF VARIATION for effects of INFLUENCE QUANTITIES . 14
4.3.1 INFLUENCE QUANTITIES . 14
4.3.2 MINIMUM RATED RANGE of use . 14
4.3.3 REFERENCE CONDITIONS . 14
4.3.4 STANDARD TEST CONDITIONS . 14
4.3.5 LIMITS OF VARIATION . 14
4.4 Performance test procedures . 16
4.4.1 General remarks . 16
4.4.2 Dependence of instrument RESPONSE on voltage waveform and
frequency . 17
4.4.3 Dependence of instrument RESPONSE on ANODE ANGLE . 17
4.4.4 Dependence of instrument RESPONSE on FILTRATION . 18
4.4.5 Dependence of instrument RESPONSE on dose rate . 18
4.4.6 Dependence of instrument RESPONSE on IRRADIATION TIME . 18
4.4.7 Dependence of instrument RESPONSE on field size . 18
4.4.8 Dependence of instrument RESPONSE on focus-to-detector distance . 19
4.4.9 Dependence of instrument RESPONSE on angle of incidence of RADIATION . 19
4.4.10 Dependence of instrument RESPONSE on angle of detector rotation with
respect to the X-RAY TUBE axis . 19
4.4.11 Dependence of instrument RESPONSE on temperature and humidity . 20
4.4.12 Dependence of instrument RESPONSE on operating voltage . 20
4.4.13 Dependence of instrument RESPONSE on electromagnetic compatibility . 21
4.4.14 Additional tungsten filtration (tube aging) . 23
5 Special instrumental requirements and marking . 23
5.1 Requirements for the complete instruments . 23
5.2 General . 23
5.3 Display . 24
5.4 Range of measurement . 24
5.5 Connectors and cables . 24
6 ACCOMPANYING DOCUMENTS . 24
6.1 General . 24
6.2 Information provided . 24
6.3 Instrument description . 24

6.4 Detector . 24
6.5 Delay time . 24
6.6 Measurement window . 24
6.7 Data outlet . 24
6.8 Transport and storage . 25
Annex A (informative) Recommended performance criteria for the invasive divider .
Annex A (informative) COMBINED STANDARD UNCERTAINTY . 27
Annex B (informative) Additional information on PRACTICAL PEAK VOLTAGE . 28
B.1 Overview. 28
B.2 Simplified formalism for the determination of the PRACTICAL PEAK VOLTAGE Û . 28
Annex C (informative) Glossary of defined terms .
Bibliography . 36
Index of defined terms . 37

Figure B.1 – Example of a waveform of a two-pulse generator . 30
Figure B.2 – Example of a waveform of a constant-voltage generator . 30
Figure B.3 – Example of falling load waveform . 31

Table 1 – Minimum effective ranges . 11
Table 2 – Minimum RATED RANGE OF USE, REFERENCE CONDITIONS, STANDARD TEST
CONDITIONS, LIMITS OF VARIATION (± L) and INTRINSIC ERROR (E) over the EFFECTIVE
RANGE of use, for the pertaining INFLUENCE QUANTITY . 15
Table 3 – Minimum test points and test values of PRACTICAL PEAK VOLTAGE for
INFLUENCE QUANTITIES . 17
Table 4 – Maximum HALF-VALUE LAYER (HVL) depending on anode angle . 23
Table A.1 – Example for assessment of the COMBINED STANDARD UNCERTAINTY –
Instruments used for NON-INVASIVE MEASUREMENT of X-RAY TUBE VOLTAGE . 27
Table B.1 – Values of 20 samples of the falling load waveform in Figure B.3 . 31
Table B.2 – Voltage bins, probability and weighting factors for the 20 samples
of the falling load waveform in Figure B.3 . 32
Table B.3 – Weighting factors for the 20 equally spaced samples of the falling load
waveform in figure B.3 . 33

– 4 – IEC 61676:2023 RLV © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT – DOSIMETRIC INSTRUMENTS
USED FOR NON-INVASIVE MEASUREMENT OF X-RAY TUBE VOLTAGE
IN DIAGNOSTIC RADIOLOGY
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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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
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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.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 61676:2002+AMD1:2008 CSV. A vertical bar appears in
the margin wherever a change has been made. Additions are in green text, deletions are
in strikethrough red text.
IEC 61676 has been prepared by subcommittee 62C: Equipment for radiotherapy, nuclear
medicine and radiation dosimetry, of IEC technical committee 62: Medical equipment, software,
and systems. It is an International Standard.
This second edition of IEC 61676 cancels and replaces first edition published in 2002,
Amendment 1:2008. This edition constitutes a technical revision.
It includes an assessment of the COMBINED STANDARD UNCERTAINTY for the performance of a
hypothetical instrument for the non-invasive measurement of the tube high voltage (in Annex A)
which replaces Annex A of the edition 1.1 titled "Recommended performance criteria for the
invasive divider".
The text of this document is based on the following documents:
Draft Report on voting
62C/830/CDV 62C/866/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
In this document 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 DOCUMENT THAT HAVE BEEN DEFINED IN CLAUSE 3 OR IN
IEC 60601-1 AND ITS COLLATERAL STANDARDS: IN SMALL CAPITALS.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
NOTE The committee knows this second edition of the document does still not address all problems associated
with non-invasive high voltage measurements. For mammography only molybdenum filtration is considered in
conjunction with a molybdenum anode although in addition tungsten and rhodium anodes with other filtrations are in
use like rhodium, aluminium, copper, silver or titanium. At the time when this document was drafted there were not
enough data available in the literature to define realistic limits of variation for these types of INFLUENCE QUANTITIES.
On the other hand, the committee was informed that several international projects were started to examine the
general behaviour of non-invasive X-ray multimeters of the main MANUFACTURERS. Results from these studies were
to be expected within about 5 years. Therefore, the committee decided to set a short stability time for the second
edition and update the document as soon as the results from these new examinations will be available.

The contents of the corrigendum 1 (2024-01) have been included in this copy.

– 6 – IEC 61676:2023 RLV © IEC 2023
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 can 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 document is based on a quantity recently 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 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 used 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 applicable, and this value serves as a guide for the LIMITS OF VARIATION
for the effects of INFLUENCE QUANTITIES.

———————
See annex B.
MEDICAL ELECTRICAL EQUIPMENT – DOSIMETRIC INSTRUMENTS
USED FOR NON-INVASIVE MEASUREMENT OF X-RAY TUBE VOLTAGE
IN DIAGNOSTIC RADIOLOGY
1 Scope and object
This document 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.
CALIBRATION and gives guidance for estimating
This document also describes the method for
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 document 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 documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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, Graphical symbols for use on equipment, available at http://www.graphical-
symbols.info/equipment
IEC 60601-1:2005, Medical electrical equipment – Part 1: General requirements for basic safety
and essential performance
IEC 60601-1:2005/AMD1:2012
IEC 60601-1:2005/AMD2:2020
IEC TR 60788:19842004, Medical radiology – Terminology Medical electrical equipment –
Glossary of defined terms
IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test. Basic EMC Publication
IEC 61000-4-3:2000, Electromagnetic compatibility (EMC) – Part 4-3: Testing and
measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test.
Basic EMC Publication
IEC 61000-4-4:1995, Electromagnetic compatibility (EMC) – Part 4-4: Testing and
measurement techniques – Electrical fast transient/burst immunity test. Basic EMC Publication
IEC 61000-4-5:1995, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement
techniques – Surge immunity test. Basic EMC Publication
IEC 61000-4-6:1996, Electromagnetic compatibility (EMC) – Part 4-6: Testing and measurement
techniques – Immunity to conducted disturbances, induced by radio-frequency fields. Basic
EMC Publication
– 8 – IEC 61676:2023 RLV © IEC 2023
IEC 61000-4-11:1994, Electromagnetic compatibility (EMC) – Part 4-11: Testing and
measurement techniques – Voltage dips, short interruptions and voltage variations immunity
tests for equipment with input current up to 16 A per phase. Basic EMC Publication
IEC 61010-1:2001, Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 1: General requirements
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 7000:19892019, Graphical symbols for use on equipment – Index and synopsis Registered
symbol
3 Terminology Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60601-1:2005,
IEC TR 60788:2004 and the following 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.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
NOTE 1 An Index of defined terms is to be found at the end of the document.
NOTE 2 A searchable IEC Glossary can be found at std.iec.ch.
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
Note 1 to entry: The maximum (minimum) effective INDICATED VALUE is the highest (lowest) in this range.
3.3
INDICATED VALUE
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 can affect the performance of an instrument (e.g., ambient
temperature etc.) and any property of the X-RAY EQUIPMENT under test that needs to shall 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 can 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
3.8
LIMITS OF VARIATION
maximum VARIATION of a PERFORMANCE CHARACTERISTIC y, permitted by this document
Note 1 to entry: 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
Note 1 to entry: 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
Note 1 to entry: The unit of this quantity is the volt (V).
3.11
MEASURED VALUE
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 1 to entry: The CONVENTIONAL TRUE VALUE is usually the value determined by the working standard with which
the instrument under test is being compared.
3.12
MINIMUM EFFECTIVE RANGE
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)

– 10 – IEC 61676:2023 RLV © IEC 2023
3.15
VOLTAGE RIPPLE
VOLTAGE at the X-RAY TUBE, r, expressed as a percentage of the peak voltage, U , over a
max
specified time interval
Note 1 to entry: The VOLTAGE RIPPLE is expressed by the formula:
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
3.16
PRACTICAL PEAK VOLTAGE
PPV
U
max
p()U ××w()U UdU
∫
U
max
U
min
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
min
Note 1 to entry: The unit of the quantity PRACTICAL PEAK VOLTAGE is the volt (V).
Note 2 to entry: 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 is
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
RATED RANGE OF USE
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: The limits of rated range are the maximum and minimum RATED values.
Note 2 to entry: 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
document.
3.18
REFERENCE CONDITION
condition 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
INTRINSIC ERROR to the CONVENTIONAL TRUE VALUE
ratio of the
=
3.21
RESPONSE
quotient of the INDICATED VALUE divided by the CONVENTIONAL TRUE VALUE
3.22
STANDARD TEST CONDITION
condition under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
STANDARD TEST VALUES
3.23
STANDARD TEST VALUE
value or a range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER, which is
permitted when carrying out CALIBRATIONS or tests on another INFLUENCE QUANTITY or
INSTRUMENT PARAMETER
3.24
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
3.25
X-RAY TUBE VOLTAGE
potential difference applied to an X-RAY TUBE between the anode and the cathode
Note 1 to entry: 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 can 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)
Mo 24 kV to 35 kV
20 kV to 50 kV
Diagnostic
W 60 kV to 120 kV
40 kV to 150 kV
CT
W 100 80 kV to 140 kV
80 70 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.

– 12 – IEC 61676:2023 RLV © IEC 2023
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.
4.2.2 Maximum error
4.2.2.1 Maximum RELATIVE INTRINSIC ERROR for voltages above 50 kV
The RELATIVE INTRINSIC ERROR, l, of PRACTICAL PEAK VOLTAGE, Û, measurements made under
STANDARD TEST CONDITIONS, shall not be greater than ±2 % over the EFFECTIVE RANGE of
voltages. This is expressed by the formula:
ˆˆ
UU−
meas true
I ≤ 0,02
ˆ
U
true
where Û is the MEASURED VALUE of PRACTICAL PEAK VOLTAGE and Û is the TRUE VALUE of
meas true
PRACTICAL PEAK VOLTAGE. The voltages for the MINIMUM EFFECTIVE RANGE are listed in
the
Table 1.
The compliance test for performance requirement for this subclause is listed under 4.2.2.2.
4.2.2.2 Maximum INTRINSIC ERROR for voltages below 50 kV
The maximum INTRINSIC ERROR, E, of PRACTICAL PEAK VOLTAGE, Û, measurements made under
STANDARD TEST CONDITIONS shall not be greater than ±1 kV over the EFFECTIVE RANGE of
voltages. This is expressed by the formula:
ˆˆ
EU −≤U 1,0 kV
meas true
where Û is the MEASURED VALUE of PRACTICAL PEAK VOLTAGE and Û is the CONVENTIONAL
meas true
TRUE VALUE of the PRACTICAL PEAK VOLTAGE. The voltages for the MINIMUM EFFECTIVE RANGE are
listed in Table 1.
Compliance with performance requirements 4.2.2.1 and 4.2.2.2 shall be checked by measuring
the RELATIVE INTRINSIC ERROR above 50 kV or the INTRINSIC ERROR below 50 kV over the
EFFECTIVE RANGE of voltages for each application claimed. STANDARD TEST CONDITIONS are listed
in Table 2 for each application. The end points of the EFFECTIVE RANGE must shall be checked.
For mammography, the nominal step between measurements shall be no greater than 2 kV. For
all other applications the nominal step between measurements shall be no greater than 5 kV
for voltages below 100 kV, and no greater than 10 kV for voltages above 100 kV.
If more than one instrument configuration can be utilised to measure a span of voltages, then
that span of voltages shall be measured utilising all relevant instrument configurations. As a
minimum the end points and enough interim points shall be measured to meet the minimum
step requirements given above. An example could be the use of different absorber pairs to
provide overlapping voltage spans. In the case of different absorber pairs, if the first measured
from 40 kV to 80 kV, and the second from 60 kV to 120 kV, then the overlapping span would be
from 60 kV to 80 kV. At a minimum, measurements would be made utilising each absorber pair
at 60 kV, 65 kV, 70 kV, 75 kV, and 80 kV.
=
=
4.2.3 Over and under range indications
The instrument must shall clearly indicate when it is displaying a reading outside its EFFECTIVE
RANGE of PRACTICAL PEAK VOLTAGE.
Conditions above and below the EFFECTIVE RANGE of PRACTICAL PEAK VOLTAGE shall be tested
and it shall be demonstrated that if the instrument displays a reading it will be clearly indicated
to the user that the reading might not meet the accuracy of the instrument.
If more than one instrument configuration can be utilised to measure a span of voltages, then
over and under range conditions shall be checked for all relevant instrument configurations. An
example could be the use of different absorber pairs to provide overlapping voltage spans. In
the case of different absorber pairs, if the first measured from 40 kV to 80 kV, and the second
from 60 kV to 120 kV, then over and under range indications would be checked below 40 kV
and above 80 kV for the first absorber pair, and below 60 kV and above 120 kV for the second
absorber pair. (The instrument’s refusal to make a reading under these conditions is an
acceptable result.)
Compliance with performance requirement of this subclause shall be verified at the lowest limit
of the RATED RANGE of dose rates. All other INFLUENCE QUANTITIES shall be at STANDARD TEST
CONDITIONS as listed in Table 2.
4.2.4 Repeatability
When a measurement is repeated with the same instrument under unaltered conditions, the
COEFFICIENT OF VARIATION of the individual measurement shall not exceed ±0,5 % or the
standard deviation shall not exceed 0,5 kV or ±0,5 %, whichever is greater.
Compliance with performance requirement of this subclause shall be checked by determining
the COEFFICIENT OF VARIATION of ten consecutive measurements taken at the lowest limit of the
RATED RANGE of dose rates. All other INFLUENCE QUANTITIES shall be at STANDARD TEST
CONDITIONS as listed in Table 2 for each application. The end points of the EFFECTIVE RANGE and
one point near the middle of the EFFECTIVE RANGE must shall be checked. The test shall be
conducted a second time with the dose rate also within STANDARD TEST CONDITIONS.
If more than one instrument configuration can be utilised to measure a span of voltages, then
the end points of that span of voltages shall be measured utilising all relevant instrument
configurations. An example could be the use of different absorber pairs to provide overlapping
voltage spans. In the case of different absorber pairs, if the first measured from 40 kV to 80 kV,
and the second from 60 kV to 120 kV, then the overlapping span would be from 60 kV to 80 kV.
At a minimum, measurements would be made utilising each absorber pair at 60 kV and 80 kV.
4.2.5 Long term stability
The design and construction shall be such that the instrument RESPONSE does not change by
more than ±2,0 % for voltages above 50 kV or by more than ±1,0 kV for voltages below 50 kV
over a period of one year. For voltages below 50 kV, the difference between the INDICATED
VALUE and CONVENTIONAL TRUE VALUE shall not change by more than ±1,0 kV over a period of
one year.
Compliance with this performance requirement shall be checked by retaining a representative
instrument, stored under STANDARD TEST CONDITIONS of temperature and relative humidity and
by measuring the RELATIVE INTRINSIC ERROR above 50 kV or the INTRINSIC ERROR below 50 kV at
a minimum of two voltages, one near the top and one near the bottom of the EFFECTIVE RANGE.
If more than one instrument configuration can be utilised to measure a span of voltages, then
the end points of that span of voltages shall be measured utilising all relevant instrument
configurations. An example could be the use of different absorber pairs to provide overlapping
voltage spans. In the case of different absorber pairs, if the first measured from 40 kV to 80 kV,

– 14 – IEC 61676:2023 RLV © IEC 2023
and the second from 60 kV to 120 kV, then the overlapping span would be from 60 kV to 80 kV.
At a minimum, measurements would be made utilising each absorber pair at 60 kV and 80 kV.
These measurements shall be made at a minimum of one-month intervals over a period of not
less than six months. Linear regression analysis shall be used to extrapolate these readings to
obtain the change in RESPONSE over one full year.
4.3 LIMITS OF VARIATION for effects of INFLUENCE QUANTITIES
4.3.1 INFLUENCE QUANTITIES
Quantities which may can influence the performance of the instrument are given in Table 2.
4.3.2 MINIMUM RATED RANGE of use
The MINIMUM RATED RANGE of use for each of the INFLUENCE QUANTITIES involved is given in
Table 2.
4.3.3 REFERENCE CONDITIONS
The REFERENCE CONDITIONS for each particular INFLUENCE QUANTITY are given in Table 2. For
those INFLUENCE QUANTITIES that can be controlled, the REFERENCE VALUE should be the value
used during the CALIBRATION of the equipment.
4.3.4 STANDARD TEST CONDITIONS
The STANDARD TEST CONDITIONS stated in Table 2 shall be met during the test procedure except
for the INFLUENCE QUANTITY being tested.
4.3.5 LIMITS OF VARIATION
The LIMITS OF VARIATION ± L for each particular INFLUENCE QUANTITY are given in Table 2. For
any change of an INFLUENCE QUANTITY within its RATED RANGE the change of the RESPONSE of
the instrument shall be such that the following relationship is fulfilled:
R
−×1 100 % ≤ L
R
ref
Table 2 – Minimum RATED RANGE OF USE, REFERENCE CONDITIONS, STANDARD
TEST CONDITIONS, LIMITS OF VARIATION (± L) and INTRINSIC ERROR (E) over
the EFFECTIVE RANGE of use, for the pertaining INFLUENCE QUANTITY
Influence quantity Minimum rated range REFERENCE STANDARD TEST ± E ± L Sub-
of use CONDITIONS CONDITIONS kV % clause
Voltage waveform
4.4.2
and frequency:
Diagnostic Constant potential, 2-, 6-, 12- Constant Constant potential, 2,0
pulse and medium frequency potential ripple less than 4 %
a
generators
Mammography Constant potential  0,5
Anode angle:   4.4.3
Diagnostic 6° to 18° 12° REFERENCE VALUE ±2°  0,5

Mammography 15° to 24° 20° REFERENCE VALUE ±2° 0,5
Filtration:    4.4.4
b
Diagnostic 3,0 mm Al REFERENCE VALUE ±5 % 1,5
2,5 mm Al to 3,5 mm Al
c
Mammography 30 μm Mo REFERENCE VALUE ±5 % 0,5
25 μm Mo to 35 μm Mo
CT 4 mm Al to 8 mm Al 6 mm Al REFERENCE VALUE ±5 % 1,5
Dental 1 mm Al to 2 mm Al 1,5 mm Al REFERENCE VALUE ±5 % 1,5
Dose rate: As stated by
MANUFACTURE REFERENCE VALUE ±20 % 0,5 4.4.5
R
Diagnostic 20 mGy/s to 200 mGy/s  0,5
Mammography 25 mGy/s to 150 mGy/s 0,5
CT 20 mGy/s to 200 mGy/s 0,5
Dental 5 mGy/s to 50 mGy/s 0,5
Fluoroscopic 1 mGy/s to 10 mGy/s
Irradiation time:
4.4.6
Diagnostic 10 ms to 1 000 ms 100 ms REFERENCE VALUE ±20 %  0,5
Other 200 ms to 1 000 ms 500 ms REFERENCE VALUE ±20 % 0,5
Field size:
Rated range Length and width stated by As stated by REFERENCE VALUE ±2 % 0,5 4.4.7.1
MANUFACTURER + 30 % to MANUFACTURE
10 % R.
Large field 30 cm by 30 cm 30 cm by REFERENCE VALUE ±2 % 2,0 4.4.7.2
30 cm
Detector-focal 32 cm to 60 cm or as stated 40 cm or as REFERENCE VALUE ±1 % 0,5 4.4.8
distance by MANUFACTURER stated by
MANUFACTURE
R
Angle of incidence
±5° 0° REFERENCE VALUE ±1° 0,5 4.4.9
Rotation
±10° 0° REFERENCE VALUE ±1° 0,5 4.4.10.1
±180° 0° REFERENCE VALUE ±1° 0,5 4.4.10.2
Temperature 15 °C to 35 °C 20 °C REFERENCE VALUE ±2 °C 1,0 4.4.11
Relative humidity 50 % 30 % to 75 %
≤ 80 % (max 20 g/m )
Power supply
Line voltage and 115 V or 230 V + 10 % to 115 V/230 V REFERENCE VALUE ±1 % 0,5 4.4.12.1
frequency 15 %
– 16 – IEC 61676:2023 RLV © IEC 2023
Influence quantity Minimum rated range REFERENCE STANDARD TEST ± E ± L Sub-
of use CONDITIONS CONDITIONS kV % clause
Batteries 50 Hz or 60 Hz 50 Hz/60 Hz REFERENCE VALUE ±1 % 0,5 4.4.12.2
as stated
Rechargeable As stated by MANUFACTURER. Fresh, mains REFERENCE VALUE ±1 % 0,5 4.4.12.3
batteries Fresh to low disconnected
IEC 61000-4-2
IEC 61000-4-3
IEC 61000-4-4
Electromagnetic Without any
Insignificant 1,0 4.4.13
compatibility disturbance
IEC 61000-4-5
IEC 61000-4-6
IEC 61000-4-11
Additional tungsten
filtration (tube 0 μm to 10 μm W 3 μm W 0 μm W to 3 μm W 2,0 4.4.14
aging)
a
Frequency range f = 50 Hz to 50 kHz, VOLTAGE RIPPLE (%) from 0 to (50 – 10log f), e.g., 0 % to 20 % at 1 000 Hz,
0 % to 3 % at 50 kHz. All frequencies above 50 kHz are treated as constant potential generators.
b
Filtration outside
...