IEC 60806:2022

IEC 60806
®

Edition 2.0 2022-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE


Determination of the maximum symmetrical radiation field of X-ray tube
assemblies and X-ray source assemblies for medical diagnosis

Détermination du champ de rayonnement maximal symétrique des gaines
équipées et des ensembles radiogènes utilisés en diagnostic médical

IEC 60806:2022-11(en-fr)

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IEC 60806

®


Edition 2.0 2022-11




INTERNATIONAL



STANDARD




NORME


INTERNATIONALE











Determination of the maximum symmetrical radiation field of X-ray tube

assemblies and X-ray source assemblies for medical diagnosis



Détermination du champ de rayonnement maximal symétrique des gaines

équipées et des ensembles radiogènes utilisés en diagnostic médical
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 11.040.50 ISBN 978-2-8322-6095-1




Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – IEC 60806:2022 © IEC 2022
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Maximum symmetrical RADIATION FIELD . 6
4.1 Orientation of the maximum symmetrical RADIATION FIELD . 6
4.2 Determination of the maximum symmetrical RADIATION FIELD . 7
5 Measurement of the distribution of AIR KERMA RATE . 7
5.1 Detector . 7
5.2 Measuring arrangement . 8
5.3 Measuring conditions . 9
6 Statement of compliance . 9
Annex A (informative) Background . 10
A.1 Overview. 10
A.2 Second edition . 10
Index of defined terms . 11

Figure 1 – Orientation of the maximum symmetrical RADIATION FIELD . 6
Figure 2 – Typical distribution of the relative AIR KERMA RATE along the major axis X of
a maximum symmetrical RADIATION FIELD . 7
Figure 3 – Measuring arrangement . 8

Table 1 – RADIATION QUALITY . 9

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IEC 60806:2022 © IEC 2022 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

DETERMINATION OF THE MAXIMUM SYMMETRICAL
RADIATION FIELD OF X-RAY TUBE ASSEMBLIES AND X-RAY
SOURCE ASSEMBLIES FOR MEDICAL DIAGNOSIS

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
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 60806 has been prepared by subcommittee 62B: Diagnostic imaging equipment, of IEC
technical committee 62: Electrical equipment in medical practice. It is an International Standard.
This second edition cancels and replaces the first edition published in 1984. This edition
constitutes a technical revision.
This edition includes the following significant technical change with respect to the previous
edition:
a) addition of solid state detectors as they have become more common since the first edition
of 1984.

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– 4 – IEC 60806:2022 © IEC 2022
The text of this document is based on the following documents:
Draft Report on voting
62B/1298/FDIS 62B/1305/RVD

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/publications.
In this document, 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: 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.

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IEC 60806:2022 © IEC 2022 – 5 –
DETERMINATION OF THE MAXIMUM SYMMETRICAL
RADIATION FIELD OF X-RAY TUBE ASSEMBLIES AND X-RAY
SOURCE ASSEMBLIES FOR MEDICAL DIAGNOSIS



1 Scope
This document is applicable to X-RAY SOURCE ASSEMBLIES and X-RAY TUBE ASSEMBLIES.
NOTE 1 If, for certain MEDICAL ELECTRICAL SYSTEMS, special radiation fields are required such that the scope of
IEC 60806 does not apply (e. g., using CT collimators with bow-tie filters), the appropriate system particular standard
applies.
This document specifies a method for the determination of the greatest geometrically
symmetrical RADIATION FIELD at a specified distance from the FOCAL SPOT for which the
percentage AIR KERMA RATE along the major axes of the RADIATION FIELD does not fall below a
permitted value.
NOTE 2 In practical use AIR KERMA or AIR KERMA RATE are the most practical physical measures to quantify X-RAY
PATTERNS.
In case multiple FOCAL SPOTS are not super-imposed, each FOCAL SPOT has its own REFERENCE
AXIS. Then the maximum RADIATION FIELD can be given for each FOCAL SPOT separately.
NOTE 3 The maximum symmetrical RADIATION FIELD can change from its initial value as the X-RAY TUBE ages through
use.
2 Normative references
The following documents are referred to in the text in such a way that some or all 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 60336:2020, Medical electrical equipment – X-ray tube assemblies for medical diagnosis –
Focal spot dimensions and related characteristics
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 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 60601-1-3:2008/AMD1:2013
IEC 60601-1-3:2008/AMD2:2021
IEC 60613:2010, Electrical and loading characteristics of X-ray tube assemblies for medical
diagnosis
IEC TR 60788:2004, Medical electrical equipment – Glossary of defined terms

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– 6 – IEC 60806:2022 © IEC 2022
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60336:2020,
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012, IEC 60601-1:2005/AMD2:2020,
IEC 60601-1-3:2008, IEC 60601-1-3:2008/AMD1:2013, IEC 60601-1-3:2008/AMD2:2021,
IEC 60613:2010, and IEC TR 60788:2004 apply.
NOTE 1 An Index of defined terms is to be found at the end of the document.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
4 Maximum symmetrical RADIATION FIELD
4.1 Orientation of the maximum symmetrical RADIATION FIELD
For the determination of the maximum symmetrical RADIATION FIELD the distribution of AIR KERMA
RATE shall be measured along two major axes in the measuring plane; see Figure 1.

Figure 1 – Orientation of the maximum symmetrical RADIATION FIELD
The major axis X is the projection in REFERENCE DIRECTION of the longitudinal axis of the X-RAY
TUBE ASSEMBLY or the X-RAY SOURCE ASSEMBLY onto the measuring plane. The major axis Y is
normal to the axis X. Both major axes intersect on the REFERENCE AXIS.
NOTE 1 Usually, both major axes are normal to the REFERENCE AXIS (see also 5.2).
The orientation of the maximum symmetrical RADIATION FIELD is shown in Figure 1. The typical
distribution in the direction of the X axis is given in Figure 2.

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IEC 60806:2022 © IEC 2022 – 7 –
NOTE 2 The limitation of the RADIATION FIELD owing to the ANODE ANGLE is called the “ANODE heel effect”. It refers
to the relatively steep decline of the AIR KERMA RATE by ATTENUATION in the ANODE for angles close to the ANODE
ANGLE.

AIR KERMA RATE along
Figure 2 – Typical distribution of the relative
the major axis X of a maximum symmetrical RADIATION FIELD
4.2 Determination of the maximum symmetrical RADIATION FIELD
A maximum symmetrical RADIATION FIELD shall be determined as the dimensions of the greatest
RADIATION FIELD at specified distance from the FOCAL SPOT symmetrical with respect to the
specified REFERENCE AXIS, with its edges parallel to the major axes, in which the distribution of
the relative AIR KERMA RATE along the major axes does not fall by more than 70 % of the AIR
KERMA RATE on the REFERENCE AXIS.
5 Measurement of the distribution of AIR KERMA RATE
5.1 Detector
For the determination of the distribution of the AIR KERMA RATE, either an X-RAY IMAGE RECEPTOR,
digital or RADIOGRAPHIC FILM, or a scanning method with a RADIATION DETECTOR shall be used.

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– 8 – IEC 60806:2022 © IEC 2022
The RADIATION FIELD shall be determined with an accuracy in width and length of 2 mm or better.
By using the conversion function for the determination method, the individual measurement
values shall be transformed into values of the AIR KERMA RATE.
5.2 Measuring arrangement
The required measuring arrangement is shown in Figure 3.

Figure 3 – Measuring arrangement
At a distance of 75 % of the specified smallest distance a of the IMAGE RECEPTION PLANE from
min
FOCAL SPOT, a FILTER according to Table 1 shall be placed of sufficient dimensions to
the
intercept the entire RADIATION FIELD.
The measuring plane shall be at the specified distance a from the FOCAL SPOT and normal to
the REFERENCE AXIS to within 2 degrees.
NOTE For referencing purposes, the distance of 1 000 mm is preferred.
If for a specified special radio-diagnostic technique the IMAGE RECEPTION PLANE is not normal to
the REFERENCE AXIS, the measuring plane shall be adjusted to the direction specified for that
technique to within 2 degrees.
In general, measurements should be performed under minimal SCATTERING and BACKSCATTERING
conditions.

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IEC 60806:2022 © IEC 2022 – 9 –
5.3 Measuring conditions
The X-RAY TUBE shall be operated as in INTENDED USE.
For securing a representative RADIATION QUALITY, the X-RAY TUBE VOLTAGE and the FILTER
thickness shall be as given in Table 1.
Table 1 – RADIATION QUALITY
NOMINAL X-RAY TUBE VOLTAGE U FILTER thickness of aluminium Required X-RAY TUBE VOLTAGE
m
kV mm kV
30 ≤ U ≤ 50 5 30
m
50 < U ≤ 75 10 50
m
75 < U ≤ 125 20 75
m
125 < U 20 75 and 125
m

NOTE 1 The determination gives the base-line RADIATION FIELD. The FILTRATION in the relevant system can influence
the effective maximal RADIATION FIELD and its uniformity.
NOTE 2 The ANODE heel-effect is more pronounced at the lower end of a given HIGH VOLTAGE range due to higher
absorption. Therefore, for each HIGH VOLTAGE range in the table, the RADIATION FIELD is determined at that critical
condition. For a large HIGH VOLTAGE range extending over 125 kV, 75 kV has thus been added to also cover this
representative application.
6 Statement of compliance
The statement of a maximum symmetrical RADIATION FIELD complying with this document shall
be as follows:
Maximum symmetrical RADIATION FIELD … mm/… mm for a HIGH VOLTAGE of … kV at a distance
from the FOCAL SPOT of … mm according to IEC 60806:2022. For the assembly, the smallest
distance from the FOCAL SPOT is … mm.

NOTE This statement can be given, if appropriate, for each FOCAL SPOT and each HIGH VOLTAGE.
The first value for a rectangular RADIATION FIELD shall be in the direction parallel to the
longitudinal axis of the X-RAY SOURCE ASSEMBLY or X-RAY TUBE ASSEMBLY.
If applicable, the IMAGE RECEPTION PLANE angle shall be stated in case this plane is not normal
to the REFERENCE AXIS (5.2).

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– 10 – IEC 60806:2022 © IEC 2022
Annex A
(informative)

Background
A.1 Overview
Owing to the increased ATTENUATION in the ANODE of an X-RAY TUBE in oblique directions, the
AIR KERMA RATE decreases towards the edge of the RADIATION FIELD in directions forming small
ANODE.
angles with the surface of the
In addition, the AIR KERMA RATE over the RADIATION FIELD decreases with distance from the
REFERENCE AXIS to the edges of the RADIATION FIELD according to the inverse square law with
respect to the distance from the FOCAL SPOT.
The AIR KERMA RATE depends on the RADIATION QUALITY and the FILTRATION. Therefore, for
simulating the situation in practice, the measuring arrangement required in this document
FILTRATION in the RADIATION BEAM. Further, practical X-RAY TUBE VOLTAGES
includes a substantial
are applied.
Furthermore, the distribution of AIR KERMA RATE is affected by, for example, SCATTERED
RADIATION from objects in the RADIATION BEAM; the position of any object in the RADIATION BEAM.
Therefore, the measuring arrangement is required to have no objects in the RADIATION BEAM
except the FILTER in its required position.
A.2 Second edition
Since the first edition in 1984, considerable developments have taken place in detector
technology. Therefore, instead of RADIOGRAPHIC FILM, solid state detectors are generally used.
The second edition thus applies such detectors, while keeping the alternative of RADIOGRAPHIC
FILM.

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IEC 60806:2022 © IEC 2022 – 11 –
Index of defined terms
ADDED FILTER . IEC 60601-1-3:2008, 3.2
AIR KERMA . IEC 60601-1:2005/AMD1:2012, 3.140
AIR KERMA RATE . IEC 60601-1-3:2008, 3.5
ANODE . IEC TR 60788:2004, rm-22-06
ANODE ANGLE . IEC TR 60788:2004, rm-22-07
ATTENUATION . IEC 60601-1-3:2008, 3.7
BACK-SCATTERING . IEC TR 60788:2004, rm-12-04
DIAPHRAGM . IEC 60601-1-3:2008, 3.17
FILTER . IEC 60601-1-3:2008, 3.23
FILTRATION . IEC 60601-1-3:2008, 3.24
FOCAL SPOT . IEC 60336:2020, 3.4
HIGH VOLTAGE . IEC 60601-1:2005, 3.41
IMAGE RECEPTION PLANE . IEC TR 60788:2004, rm-37-15
INTENDED USE . IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012,
. IEC 60601-1:2005/AMD2:2020, 3.44
MEDICAL ELECTRICAL SYSTEM . IEC 60601-1:2005, 3.64
NOMINAL X-RAY TUBE VOLTAGE . IEC 60601-1-3:2008, 3.42
RADIATION BEAM . IEC 60601-1-3:2008, 3.55
RADIATION DETECTOR . IEC 60601-1-3:2008, 3.57
RADIATION FIELD . IEC 60601-1-3:2008, 3.58
RADIATION QUALITY . IEC 60601-1-3:2008, 3.60
RADIOGRAPHIC FILM . IEC TR 60788:2004, rm-32-32
REFERENCE AXIS . IEC 60336:2020, 3.10
REFERENCE DIRECTION . IEC 60336:2020, 3.11
REFERENCE PLANE . IEC 60336:2020, 3.12
SCATTERED RADIATION . IEC 60601-1-3:2008, 3.73
SCATTERING . IEC TR 60788:2004, rm-12-03
X-RAY IMAGE RECEPTOR . IEC 60601-1-3:2008, 3.81
X-RAY PATTERN . IEC 60601-1-3:2008, 3.82
X-RAY SOURCE ASSEMBLY…. .IEC 60601-1-3:2008, 3.62
X-RAY TUBE. .IEC 60601-1-3:2008, 3.83
X-RAY TUBE ASSEMBLY . IEC 60601-1-3:2008, 3.84
X-RAY TUBE VOLTAGE . IEC 60613:2010, 3.1

___________

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– 12 – IEC 60806:2022 © IEC 2022
SOMMAIRE
AVANT-PROPOS . 13
1 Domaine d’application . 15
2 Références normatives . 15
3 Termes et définitions . 16
4 CHAMP DE RAYONNEMENT maximal symétrique. 16
4.1 Orientation du CHAMP DE RAYONNEMENT maximal symétrique . 16
4.2 Détermination du CHAMP DE RAYONNEMENT maximal symétrique . 17
5 Mesurage de la répartition du DEBIT DE KERMA DANS L’AIR . 17
5.1 Détecteur . 17
5.2 Dispositif de mesure . 18
5.3 Conditions de mesure . 19
6 Déclaration de conformité . 19
Annexe A (informative) Contexte. 20
A.1 Vue d’ensemble . 20
A.2 Deuxième édition . 20
Index des termes définis .
...