IEC 60522-1:2020

Medical electrical equipment - Diagnostics X-rays - Part 1: Determination of quality equivalent filtration and permanent filtration

IEC 60522-1:2020 applies to X-RAY TUBE ASSEMBLIES and to FILTERING MATERIAL, in medical diagnostic applications up to a HIGH VOLTAGE of 150 kV. For HIGH VOLTAGES greater than 50 kV, this document applies to X-RAY TUBE ASSEMBLIES with tungsten or tungsten-alloy TARGETS only.
IEC 60522-1:2021 defines the concept of PERMANENT FILTRATION of X-RAY TUBE ASSEMBLIES, and it defines the term FILTERING MATERIAL.
Methods are given to determine the PERMANENT FILTRATION of an X-RAY TUBE ASSEMBLY and for determining the QUALITY EQUIVALENT FILTRATION of FILTERING MATERIALS.
It contains requirements for statements of compliance of X-RAY TUBE ASSEMBLIES in ACCOMPANYING DOCUMENTS and for markings on X-RAY TUBE ASSEMBLIES, and for indications and statements of compliance of FILTERING MATERIAL.
IEC 60522-1:2020 cancels and replaces the second edition of IEC 60522 published in 1999. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the IEC 60522:1999:
The scope of the IEC 60522-1 has been changed with respect to second edition of the IEC 60522 as follows:
a) As radiotherapy standards do not reference IEC 60522, radiotherapy is no longer in the scope. Consequently, the HIGH VOLTAGE is limited to 150 kV, and copper is no longer used as reference material.
b) While IEC 60522:1999 covers only PERMANENT FILTRATION, IEC 60522-1 also covers quite generally “material filtering the X-RAY BEAM incident on the PATIENT”. This concerns materials like ADDED FILTERS, table-tops, a breast COMPRESSION DEVICE, and materials in the BEAM LIMITING DEVICE. For these materials the defined term FILTERING MATERIAL has been introduced.
c) In order to provide technical and scientific background and rationale on the content of IEC 60522-1, IEC TR 60522-2 was introduced.

Appareils électromédicaux - Rayonnements X de diagnostic - Partie 1: Détermination de la filtration de qualité équivalente et de la filtration permanente

L'IEC 60522-1:2020 s’applique aux GAINES EQUIPEES et au MATERIAU DE FILTRAGE, dans les applications de diagnostic médical soumises à une HAUTE TENSION maximale de 150 kV. Pour les HAUTES TENSIONS supérieures à 50 kV, le présent document s’applique aux GAINES EQUIPEES avec CIBLES en tungstène ou en alliage de tungstène uniquement.
L'IEC 60522-1:2020 définit le concept de FILTRATION PERMANENTE des GAINES EQUIPEES ainsi que le terme MATERIAU DE FILTRAGE.
Des méthodes sont données pour déterminer la FILTRATION PERMANENTE d’UNE GAINE EQUIPEE ainsi que la FILTRATION DE QUALITE EQUIVALENTE des MATERIAUX DE FILTRAGE.
Il comprend des exigences relatives aux déclarations de conformité des GAINES EQUIPEES dans les DOCUMENTS D’ACCOMPAGNEMENT et aux marquages sur les GAINES EQUIPEES, ainsi qu’aux indications et déclarations de conformité du MATERIAU DE FILTRAGE.
L'IEC 60522-1:2020 annule et remplace la seconde édition de l’IEC 60522 parue en 1999. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l’IEC 60522:1999.
Le domaine d’application de l’IEC 60522-1 a été modifié par rapport à la deuxième édition de l’IEC 60522 comme suit:
a) Les normes de radiothérapie ne faisant pas référence à l’IEC 60522, la radiothérapie ne fait plus partie du domaine d’application. Par conséquent, la HAUTE TENSION est limitée à 150 kV et le cuivre n’est plus utilisé comme matériau de référence.
b) Alors que l’IEC 60522:1999 traite uniquement de la FILTRATION PERMANENTE, l’IEC 60522 1 traite également de façon plus générale du "matériau filtrant le FAISCEAU DE RAYONNEMENT X incident sur le PATIENT". Ceci concerne des matériaux tels que des FILTRES ADDITIONNELS, des plateaux de table, un DISPOSITIF DE COMPRESSION du sein et des matériaux présents dans le LIMITEUR DE FAISCEAU. Le terme défini de MATERIAU DE FILTRAGE est employé pour désigner ces matériaux.
c) L’IEC TR 60522-2 a été ajouté afin de fournir un contexte et une justification techniques et scientifiques sur le contenu de l’IEC 60522-1.

General Information

• Status: Published
• Publication Date: 03-Dec-2020
• ICS: 11.040.50 - Radiographic equipment
• Technical Committee: SC 62B - Medical imaging equipment, software, and systems
• Drafting Committee: MT 32 - TC 62/SC 62B/MT 32
• Current Stage: PPUB - Publication issued
• Start Date: 11-Dec-2020
• Completion Date: 04-Dec-2020

Relations

• Replaces: IEC 60522:1999 - Determination of the permanent filtration of X-ray tube assemblies
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60522-1 ®
Edition 1.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment – Diagnostic X-rays –
Part 1: Determination of quality equivalent filtration and permanent filtration

Appareils électromedicaux – Rayonnements X de diagnostic –
Partie 1: Détermination de la filtration de qualité équivalenteet de la filtration
permanente
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IEC 60522-1 ®
Edition 1.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment – Diagnostic X-rays –

Part 1: Determination of quality equivalent filtration and permanent filtration

Appareils électromedicaux – Rayonnements X de diagnostic –

Partie 1: Détermination de la filtration de qualité équivalenteet de la filtration

permanente
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 11.040.50 ISBN 978-2-8322-9036-1

– 2 – IEC 60522-1:2020 © IEC 2020
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Determination of QUALITY EQUIVALENT FILTRATION . 7
4.1 Alignment of X-RAY TUBE ASSEMBLIES and of the FILTERS . 7
4.2 Generation of the X-RAY BEAM for the determination . 7
4.3 Requirements for RADIATION DETECTOR . 8
4.4 Composition of reference material . 8
4.5 Determination of PERMANENT FILTRATION . 8
4.5.1 Guideline . 8
4.5.2 Direct determination of PERMANENT FILTRATION . 9
4.5.3 Indirect determination of PERMANENT FILTRATION – general case . 10
4.5.4 Indirect determination of PERMANENT FILTRATION – special case . 12
4.6 Determination of the QUALITY EQUIVALENT FILTRATION of a FILTERING MATERIAL
or of a stack of FILTERING MATERIALS . 13
4.6.1 Choice of TARGET ANGLE . 13
4.6.2 Determination method. 13
4.7 X-ray simulations . 15
4.8 Compliance test . 15
5 Indications and statements of QUALITY EQUIVALENT FILTRATION . 15
5.1 Presentation of QUALITY EQUIVALENT FILTRATION values . 15
5.2 Indications and statements of PERMANENT FILTRATION . 15
5.3 Indications and statements of FILTERING MATERIALS . 16
Annex A (informative) Historical background . 17
A.1 General . 17
A.2 The first edition of IEC 60522 (1976) . 17
A.3 The second edition of IEC 60522 (1999) . 17
A.4 The first edition of IEC 60522-1 (2020) . 17
Bibliography . 18
Index of defined terms . 19

Figure 1 – Measurement steps for determining the PERMANENT FILTRATION of an X-RAY
TUBE ASSEMBLY using a reference X-RAY TUBE ASSEMBLY . 9
Figure 2 – Measurement steps for determining the QUALITY EQUIVALENT FILTRATION of a
FILTER – general case . 11
Figure 3 – Measurement steps for determining the QUALITY EQUIVALENT FILTRATION of a
FILTER – special case . 12
Figure 4 – Measurement steps for determining the QUALITY EQUIVALENT FILTRATION of
FILTERING MATERIAL . 14

Table 1 – Overview for the selection of methods for the determination of PERMANENT
FILTRATION and of the QUALITY EQUIVALENT FILTRATION (QEF) . 9

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT – DIAGNOSTIC X-RAYS –

Part 1: Determination of quality equivalent
filtration and permanent filtration

FOREWORD
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60522-1 has been prepared by subcommittee 62B: Diagnostic
imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice.
This first edition cancels and replaces the second edition of IEC 60522 published in 1999. This
edition constitutes a technical revision. This edition includes the following significant technical
changes with respect to the IEC 60522:1999:
The scope of the IEC 60522-1 has been changed with respect to second edition of the
IEC 60522 as follows:
a) As radiotherapy standards do not reference IEC 60522, radiotherapy is no longer in the
scope. Consequently, the HIGH VOLTAGE is limited to 150 kV, and copper is no longer used
as reference material.
– 4 – IEC 60522-1:2020 © IEC 2020
b) While IEC 60522:1999 covers only PERMANENT FILTRATION, IEC 60522-1 also covers quite
generally “material filtering the X-RAY BEAM incident on the PATIENT”. This concerns materials
like ADDED FILTERS, table-tops, a breast COMPRESSION DEVICE, and materials in the BEAM
LIMITING DEVICE. For these materials the defined term FILTERING MATERIAL has been
introduced.
c) In order to provide technical and scientific background and rationale on the content of
IEC 60522-1, IEC TR 60522-2 [2] was introduced.
The text of this document is based on the following documents:
FDIS Report on voting
62B/1201/FDIS 62B/1213/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60522 series, published under the general title Medical electrical
equipment – Diagnostic X-rays, can be found on the IEC website.
In this document, the following print types are used:
– requirements and definitions: roman type;
– TERMS DEFINED IN CLAUSE 3 OF THIS DOCUMENT OR LISTED IN THE INDEX: 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 "http://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.
_____________
Numbers in square brackets refer to the Bibliography.

INTRODUCTION
The review of the second edition of IEC 60522 published in 1999 pointed to a number of
technical issues. The analysis of these issues is laid down in the accompanying Technical
Report, IEC TR 60522-2 [2]. This Technical Report identifies those items which are
substantially modified in the first edition of IEC 60522-1 compared with the second edition of
IEC 60522, and elucidates the analyses which led to the many new rationales and new
approaches for the determination of the QUALITY EQUIVALENT FILTRATION.
While the second edition of IEC 60522 covers only PERMANENT FILTRATION, IEC 60522-1 also
covers quite generally “material filtering the X-RAY BEAM incident on the PATIENT”. This concerns
materials like ADDED FILTERS, a PATIENT table, a breast COMPRESSION DEVICE, and materials in
the BEAM LIMITING DEVICE. For these materials the defined term FILTERING MATERIAL has been
introduced.
With the extension by FILTERING MATERIAL, IEC 60522-1 now explicitly covers what IEC 60601-
1-3:2008 requires in its Subclause 7.4 for irremovable materials, i.e.  represented FILTRATION by irremovable materials in an X-RAY SOURCE ASSEMBLY ……. If this
information is not obtainable, determine the QUALITY EQUIVALENT FILTRATION in accordance with
IEC 60522>.
– 6 – IEC 60522-1:2020 © IEC 2020
MEDICAL ELECTRICAL EQUIPMENT – DIAGNOSTIC X-RAYS –

Part 1: Determination of quality equivalent
filtration and permanent filtration

1 Scope
This document applies to X-RAY TUBE ASSEMBLIES and to FILTERING MATERIAL, in medical
diagnostic applications up to a HIGH VOLTAGE of 150 kV. For HIGH VOLTAGES greater than 50 kV,
this document applies to X-RAY TUBE ASSEMBLIES with tungsten or tungsten-alloy TARGETS only.
NOTE 1 The FILTERING MATERIAL in the X-RAY BEAM can be removable or irremovable; it can be positioned in any
orientation or can have any shape (e.g. tapering thickness) – although usually plane-parallel material, perpendicular
to the REFERENCE AXIS is applied. Examples of FILTERING MATERIALS are ADDED FILTERS, a PATIENT table (in case of
an under-table X-RAY TUBE ASSEMBLY), materials in the BEAM LIMITING DEVICE, or a breast COMPRESSION DEVICE.
NOTE 2 The methodology and statement of compliance given in this document is for flat FILTERS only, but the
methodology can be used for any kind of non-flat FILTER. In that case further data are included in order to produce
useful results, e.g. field size, geometry/position of FILTER, etc.
This document defines the concept of PERMANENT FILTRATION of X-RAY TUBE ASSEMBLIES, and it
defines the term FILTERING MATERIAL.
Methods are given to determine the PERMANENT FILTRATION of an X-RAY TUBE ASSEMBLY and for
determining the QUALITY EQUIVALENT FILTRATION of FILTERING MATERIALS.
It contains requirements for statements of compliance of X-RAY TUBE ASSEMBLIES in
ACCOMPANYING DOCUMENTS and for markings on X-RAY TUBE ASSEMBLIES, and for indications and
statements of compliance of FILTERING MATERIAL.
NOTE 3 This document does not contain requirements for any specific values of PERMANENT FILTRATION. For X-RAY
EQUIPMENT used for diagnostic purposes, FILTRATION requirements are given in e.g. IEC 60601-1-3:2008 and
IEC 60601-1-3:2008/AMD1:2013 or in the applicable particular standard.
NOTE 4 The method of determination described in this document is suitable as a type test. It is not intended as a
test to be applied by the USER.
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 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 TR 60788:2004, Medical electrical equipment – Glossary of defined terms

IEC 61674:2012, Medical electrical equipment – Dosimeters with ionization chambers and/or
semiconductor detectors as used in X-ray diagnostic imaging
3 Terms and definitions
For the purposes of this document, the terms and definitions given in 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 TR 60788:2004 and the following apply.
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
3.1
FILTERING MATERIAL
material between the X-RAY TUBE ASSEMBLY and the PATIENT which causes FILTRATION of the
X-RAY BEAM
3.2
PERMANENT FILTRATION
QUALITY EQUIVALENT FILTRATION effected in an X-RAY TUBE ASSEMBLY by permanently fixed
materials intercepting the X-RAY BEAM, that are not intended to be removed for any application
and are not provided with means for removal in NORMAL USE
3.3
QUALITY EQUIVALENT FILTRATION
quantitative indication of the FILTRATION effected by one or several layer(s) of reference
RADIATION QUALITY under NARROW BEAM
material(s) which, if substituted in a beam of specified
CONDITION for the material under consideration, give(s) the same RADIATION QUALITY as for the
material under consideration
Note 1 to entry: The QUALITY EQUIVALENT FILTRATION is expressed in suitable submultiples of the metre together
with the reference material(s).
Note 2 to entry: In this document, RADIATION QUALITY is characterized by its first HALF-VALUE LAYER.
[SOURCE IEC 60601-1-3:2008, 3.52, modified – Addition of a new Note 2 to entry.]
4 Determination of QUALITY EQUIVALENT FILTRATION
4.1 Alignment of X-RAY TUBE ASSEMBLIES and of the FILTERS
If, apart from the X-RAY TUBE ASSEMBLY under test, a reference X-RAY TUBE ASSEMBLY is used,
then their REFERENCE AXES shall be aligned.
NOTE The alignment of the REFERENCE AXES is important, as the HALF-VALUE LAYER depends strongly on the
effective TARGET ANGLE. Simulations show, that at the typical mammographic HIGH VOLTAGE of 30 kV, the typical error
in PERMANENT FILTRATION is of the order of 1,5 % per one-degree misalignment. At the typical radiographic HIGH
VOLTAGE of 75 kV, it is of the order of 4 %.
Unless otherwise stated, the FILTERS are positioned perpendicular to the REFERENCE AXIS.
4.2 Generation of the X-RAY BEAM for the determination
The PERCENTAGE RIPPLE shall not be larger than 10 %.
It is recommended to limit the PERCENTAGE RIPPLE to 4 %, in order to maintain accuracy,

– 8 – IEC 60522-1:2020 © IEC 2020
– if the HIGH VOLTAGE is smaller than 50 kV, or
– if the HIGH VOLTAGE is larger than 50 kV and if the atomic number of the FILTERS is larger
than 30, or
– if the HIGH VOLTAGE is larger than 50 kV and the atomic number of the FILTERS is not larger
than 30, while the sum of the QUALITY EQUIVALENT FILTRATION of all materials with atomic
number not larger than 26 is smaller than 0,5 mm Al.
The HIGH VOLTAGE shall be kept constant during all the steps in the determination.
NOTE Stability of the HIGH VOLTAGE during the determination is important, as the HALF-VALUE LAYER depends
strongly on the HIGH VOLTAGE. HIGH VOLTAGE-shift of the order of 1 % in one of the steps of the determination can
lead to an error in the determined value of the QUALITY EQUIVALENT FILTRATION of the order of 10 %.
Unless other standards prescribe the HIGH VOLTAGE, the following values of the HIGH VOLTAGE
are recommended:
– for mammographic applications, 28 kV,
– for dental applications, 60 kV,
– for any other application, 75 kV,
– unless the application does not include 75 kV or is centred outside 75 kV; then it is
recommended to apply a HIGH VOLTAGE in the range of the application.
4.3 Requirements for RADIATION DETECTOR
An AIR KERMA RATE RADIATION DETECTOR shall be used which complies with the requirements of
IEC 61674:2012 for the beam qualities seen by the detector during the QUALITY EQUIVALENT
FILTRATION-determination.
NOTE This requirement ensures that the detector used has a sufficiently flat AIR KERMA RATE response.
4.4 Composition of reference material
Values of HALF-VALUE LAYER and QUALITY EQUIVALENT FILTRATION determined in accordance with
this document apply to the reference material aluminium with 99,9 % purity or higher and density
2,70 g/cm .
4.5 Determination of PERMANENT FILTRATION
4.5.1 Guideline
NOTE For guidance and overview, Table 1 serves to support selecting the appropriate method for determining the
QUALITY EQUIVALENT FILTRATION. It does not replace the text of the paragraphs 4.5.2 to 4.5.4, which are to be
referenced to take the final decision on the method to be applied.

Table 1 – Overview for the selection of methods for the determination of PERMANENT
FILTRATION
Object under test Method for X-ray source(s) required HIGH VOLTAGE Figure
PERMANENT number
FILTRATION
Original X-RAY TUBE
ASSEMBLY with PERMANENT
X-RAY TUBE ASSEMBLY with
direct FILTRATION and X-RAY TUBE ≤150 kV Figure 1
PERMANENT FILTRATION
ASSEMBLY with minimal
FILTRATION
(Stack of) PERMANENT X-RAY TUBE ASSEMBLY with
indirect ≤150 kV Figure 2
FILTRATION materials minimal FILTRATION
Separate individual
Reference X-RAY TUBE
FILTER(S) or stack(s) of
ASSEMBLY whose X-RAY BEAM
FILTERS comprising the ≥50 kV and
indirect is only filtered by materials Figure 3
PERMANENT FILTRATION, the ≤150 kV
with Z ≤ 26, with a QEF of at
QEF-values of which can
least 0,5 mm Al
reliably be added
4.5.2 Direct determination of PERMANENT FILTRATION
For the direct determination, i.e. while applying a reference X-RAY TUBE ASSEMBLY with minimal
PERMANENT FILTRATION, the measurement arrangement indicated in Figure 1, is used.

Figure 1 – Measurement steps for determining the PERMANENT FILTRATION of an X-RAY
TUBE ASSEMBLY using a reference X-RAY TUBE ASSEMBLY
Steps for determining the PERMANENT FILTRATION:

– 10 – IEC 60522-1:2020 © IEC 2020
1a With the X-RAY TUBE ASSEMBLY under test, measure the AIR KERMA RATE 𝐾𝐾̇ at a fixed
reference HIGH VOLTAGE under the conditions stated in 4.2, using a suitable RADIATION
DETECTOR (D) as described in 4.3.
1b Using an iterative measurement process, determine the HALF-VALUE LAYER referenced to
aluminium of the X-RAY BEAM by adding aluminium reference FILTERS (R) into the beam
until the AIR KERMA RATE is halved from the value determined in step 1a.
1c Substitute a reference X-RAY TUBE ASSEMBLY with minimal PERMANENT FILTRATION (e.g. a
beryllium window X-RAY TUBE ASSEMBLY with all intervening layers of material in the X-
RAY BEAM removed) in place of the X-RAY TUBE ASSEMBLY under test. The reference X-
RAY TUBE ASSEMBLY shall have a TARGET with negligible roughness, and the TARGET shall
be of the same material and have the same TARGET ANGLE as the TARGET of the X-RAY
TUBE ASSEMBLY under test. While maintaining the reference FILTERS (R) determined from
step 1b in the beam, place an aluminium FILTER (Al) into the beam and measure the
resulting AIR KERMA RATE 𝐾𝐾̇. Using an iterative measurement process, adjust the total
thickness of the FILTER (Al) such that in step 1d the AIR KERMA RATE is doubled. The
resulting thickness of the FILTER (Al) represents the PERMANENT FILTRATION of the X-RAY
TUBE ASSEMBLY under test (indicated by the dashed arrow in Figure 1).
NOTE The intent of the term negligible roughness is to make sure the USER uses a tube with a non-damaged anode
without major cracks, fissures, or signs of surface melting, e.g. a new tube after minimal seasoning.
1d Remove reference FILTERS (R) and compare the AIR KERMA RATE to the value determined
in step 1c. The value at 1d shall be twice as large.
4.5.3 Indirect determination of PERMANENT FILTRATION – general case
The PERMANENT FILTRATION may also be determined in an indirect way, by determining the
QUALITY EQUIVALENT FILTRATION of the individual material(s) of the PERMANENT FILTRATION. If the
PERMANENT FILTRATION consists of one FILTER, then its QUALITY EQUIVALENT FILTRATION is the
PERMANENT FILTRATION. For the determination in this case, the method indicated in Figure 2
shall be used for the FILTER itself (F1) or for a representative sample.
PERMANENT FILTRATION consists of a combination of materials, then the method indicated
If the
in Figure 2 may be used for the combination of materials or for a representative stack of
materials.
First, the HALF-VALUE LAYER of the output from the source and the FILTER F1 is determined (steps
2a – 2b). Finally, the FILTER F1 is removed and a new FILTER Al is inserted and iteratively
adjusted until the HALF-VALUE LAYER is the same as above (steps 2c – 2d).

Figure 2 – Measurement steps for determining the QUALITY EQUIVALENT FILTRATION
of a FILTER – general case
Steps for determining the QUALITY EQUIVALENT FILTRATION:
2a The X-RAY TUBE ASSEMBLY used for this test shall have minimal PERMANENT FILTRATION
(e.g. a beryllium window X-RAY TUBE ASSEMBLY with all intervening layers of material in
the X-RAY BEAM path removed) and shall have a TARGET with negligible roughness. The
TARGET shall be of the same material and have the same TARGET ANGLE as the TARGET
of the X-RAY TUBE ASSEMBLY under test. Place the FILTER (F1) to be measured in the X-
RAY BEAM. Measure the AIR KERMA RATE 𝐾𝐾̇ at a fixed reference HIGH VOLTAGE, under the
conditions stated in 4.2, using a suitable RADIATION DETECTOR (D) as described in 4.3.
2b Using an iterative measurement process, determine the HALF-VALUE LAYER referenced to
aluminium of the X-RAY BEAM by adding aluminium reference FILTERS (R) into the beam
until the AIR KERMA RATE is one-half of the value determined in step 2a.
2c While maintaining the reference FILTERS (R) determined from step 2b in the beam,
remove the FILTER (F1) and replace it with aluminium FILTER (Al) and measure the
AIR KERMA RATE 𝐾𝐾̇. Using an iterative measurement process, adjust the total
resulting
thickness of the FILTER (Al) such that the AIR KERMA RATE is doubled in step 2d. The
resulting thickness of the FILTER (Al) represents the QUALITY EQUIVALENT FILTRATION of the
FILTER (F1) under test (indicated by the dashed arrow in Figure 2).
2d Remove reference FILTERS (R) and compare the AIR KERMA RATE to the value determined
in step 2c. The value at 2d shall be twice as large.

– 12 – IEC 60522-1:2020 © IEC 2020
4.5.4 Indirect determination of PERMANENT FILTRATION – special case
If the PERMANENT FILTRATION of the combination of materials could reliably be found by addition
of the QUALITY EQUIVALENT FILTRATION of the individual FILTERS or of the appropriate
(sub-)stack(s), then the method in Figure 3 may be applied for the individual FILTERS or
(sub-)stack(s). The PERMANENT FILTRATION is then found by adding the QUALITY EQUIVALENT
FILTRATIONS of the FILTERS and/or (sub-)stack(s).
The boundary conditions for this case are as follows:
The HIGH VOLTAGE is at least 50 kV, and none of the materials comprising the PERMANENT
FILTRATION:
– has an atomic number larger than 26,
or
QUALITY EQUIVALENT FILTRATION of
– has an atomic number larger than 30, and the sum of the
all other materials building the PERMANENT FILTRATION with atomic number 26 or smaller is
at least 0,5 mm Al.
NOTE Under these conditions the PERMANENT FILTRATION or the QUALITY EQUIVALENT FILTRATION of its constituent
FILTERS hardly depend on the RADIATION QUALITY i.e. on HIGH VOLTAGE or TARGET ANGLE – so addition of QUALITY
EQUIVALENT FILTRATION values is appropriate.

Figure 3 – Measurement steps for determining the QUALITY EQUIVALENT FILTRATION
of a FILTER – special case
Steps for determining the QUALITY EQUIVALENT FILTRATION:
RAY TUBE ASSEMBLY used produces an X-RAY BEAM which is filtered only
3a The reference X-
by materials with atomic number not larger than 26, with a combined QUALITY EQUIVALENT
FILTRATION of at least 0,5 mm Al. Its TARGET shall be of the same material as the TARGET
of the X-RAY TUBE ASSEMBLY under test. Place the FILTER (F2), or (sub-)FILTER-stack (F2)
to be measured in the X-RAY BEAM. Measure the AIR KERMA RATE 𝐾𝐾̇ at a HIGH VOLTAGE
under the conditions stated in 4.2, using a suitable RADIATION DETECTOR (D) as described
in 4.3.
3b Using an iterative measurement process, determine the HALF-VALUE LAYER referenced to
aluminium of the X-RAY BEAM by adding aluminium reference FILTERS (R) into the beam
until the AIR KERMA RATE is one-half of the value determined in step 3a.
3c While maintaining the reference FILTERS (R) determined from step 3b in the beam,
remove the FILTER (F2) or (sub-)stack (F2) and replace it with aluminium FILTER (Al) and
measure the resulting AIR KERMA RATE 𝐾𝐾̇. Using an iterative measurement process,
adjust the total thickness of the FILTER (Al) such that in step 3d the AIR KERMA RATE is
doubled. The resulting thickness of the FILTER (Al) represents the QUALITY EQUIVALENT
FILTRATION of the FILTER (F2) or (sub-)stack (F2) under test (indicated by the dashed
arrow in Figure 3).
3d Remove reference FILTERS (R) and compare the AIR KERMA RATE to the value determined
in step 3c. The value at 3d shall be twice as large.
4.6 Determination of the QUALITY EQUIVALENT FILTRATION of a FILTERING MATERIAL or of a
stack of FILTERING MATERIALS
4.6.1 Choice of TARGET ANGLE
Usually, the QUALITY EQUIVALENT FILTRATION depends on the RADIATION QUALITY, hence it
depends also on TARGET ANGLE.
If the FILTERING MATERIAL is combined with just one X-RAY TUBE ASSEMBLY, it is recommended to
perform the determination with an X-RAY TUBE ASSEMBLY with a TARGET with the same TARGET
ANGLE.
If it is not known with which X-RAY TUBE ASSEMBLY the FILTERING MATERIAL will be used, then it
is recommended to apply an X-RAY TUBE ASSEMBLY with a representative TARGET ANGLE such,
that the deviation of the QUALITY EQUIVALENT FILTRATION over the typical range OF TARGET ANGLES
in practical applications is minimized. For mammographic applications, this representative
TARGET ANGLE is 10 ° or 11 °; for applications above a HIGH VOLTAGE of 50 kV, this representative
TARGET ANGLE is 10 °, 11 °, or 12 °.
4.6.2 Determination method
If required per IEC 60601-1-3:2008 or per another document, the reference X-RAY TUBE
ASSEMBLY used for the determination in Figure 4 is equipped with FILTRATION for the intended
RADIATION QUALITY; otherwise a reference X-RAY TUBE ASSEMBLY with minimal FILTRATION is
applied. The TARGET material is chosen in line with the application.

– 14 – IEC 60522-1:2020 © IEC 2020

Figure 4 – Measurement steps for determining the QUALITY EQUIVALENT FILTRATION
of FILTERING MATERIAL
Steps for determining the QUALITY EQUIVALENT FILTRATION:
4a Place the FILTERING MATERIAL(S) (F3) to be measured in the X-RAY BEAM. Measure the AIR
KERMA RATE 𝐾𝐾̇ at a HIGH VOLTAGE under the conditions stated in 4.2, using a suitable
RADIATION DETECTOR (D) as described in 4.3.
4b Using an iterative measurement process, determine the HALF-VALUE LAYER referenced to
aluminium of the X-RAY BEAM by adding aluminium reference FILTERS (R) into the beam
until the AIR KERMA RATE is one-half of the value determined in step 4a.
4c While maintaining the reference FILTERS (R) determined from step 4b in the beam,
remove the FILTERING MATERIAL(S) (F3) and replace it with aluminium FILTER (Al) and
measure the resulting AIR KERMA RATE 𝐾𝐾̇. Using an iterative measurement process,
adjust the total thickness of the FILTER (Al) such that in step 4d the AIR KERMA RATE is
doubled. The resulting thickness of the FILTER (Al) represents the QUALITY EQUIVALENT
FILTRATION of the FILTERING MATERIAL(S) (F3) under test (indicated by the dashed arrow
in Figure 4).
4d Remove reference FILTERS (R) and compare the AIR KERMA RATE to the value determined
in step 4c. The value at 4d shall be twice as large.

4.7 X-ray simulations
A software tool may be used to simulate the RADIATION QUALITY and to determine the QUALITY
EQUIVALENT FILTRATION. If the method of simulation has been validated against the method
described in this document over the full range of use, including consideration of K-edge issues,
also a simulation can be used as base for a statement of compliance. The validated computed
value of the QUALITY EQUIVALENT FILTRATION shall not be larger than the MEASURED VALUE. On
request, the documentation of the method of validation and the results achieved shall be made
USERS of the product documentation which includes the corresponding statement
available to
of compliance. It shall be stated that a computed value is provided.
4.8 Compliance test
Compliance with a stated value of PERMANENT FILTRATION or with a stated value of the QUALITY
EQUIVALENT FILTRATION of a FILTERING MATERIAL is achieved if the MEASURED VALUE determined
in the above tests is not less than the stated value and does not exceed the stated value by
more than 30 %.
5 Indications and statements of QUALITY EQUIVALENT FILTRATION
5.1 Presentation of QUALITY EQUIVALENT FILTRATION values
The value of the QUALITY EQUIVALENT FILTRATION shall be expressed as the thickness in
millimetres of the reference material aluminium, described by its chemical symbol.
QUALITY EQUIVALENT FILTRATION values should be presented with a maximum of one decimal
place accuracy and a maximum of two significant figures.
NOTE The indicated accuracy is in line with the limited accuracy of QUALITY EQUIVALENT FILTRATION determinations;
see IEC TR 60522-2 [2].
5.2 Indications and statements of PERMANENT FILTRATION
If an indication or statement of compliance for PERMANENT FILTRATION with this document is to
be given, it shall take the applicable form, as given below as an example, which applies to a
stated value of 1,2 mm aluminium determined at HIGH VOLTAGE of 75 kV:
ACCOMPANYING DOCUMENTS:
a) for written statements, for example in
PERMANENT FILTRATION 1,2 mm Al/75 kV IEC 60522-1:2020
RAY TUBE ASSEMBLY:
b) for markings on the X-
1,2 Al/75 or 1,2 Al/75
NOTE 1 The symbol for the marking is IEC 60417-5381:2002-10 [1].
The HIGH VOLTAGE at which the PERMANENT FILTRATION has been determined may be omitted if
the HIGH VOLTAGE is at least 50 kV, and none of materials comprising the PERMANENT FILTRATION:
– has an atomic number larger than 26,
or
– has an atomic number larger than 30, while the sum of the QUALITY EQUIVALENT FILTRATION
of all materials with atomic number 26 or smaller is at least 0,5 mm Al.

– 16 – IEC 60522-1:2020 © IEC 2020
Under these circumstances it shall take the form as shown in example below:
a) for written statements, for example in ACCOMPANYING DOCUMENTS:
PERMANENT FILTRATION 1,2 mm Al IEC 60522-1:2020
RAY TUBE ASSEMBLY:
b) for markings on the X-
1,2 Al or 1,2 Al
NOTE 2 The symbol for the marking is IEC 60417-5381:2002-10 [1].
NOTE 3 IEC 60522-1 does not include the case of stating actual FILTERING MATERIAL (e.g. beryllium). See
IEC 60601-2-28 [3] or IEC 60601-1-3 for requirements.
In case the materials building the PERMANENT FILTRATION have non-uniform thickness and/or are
non-perpendicular to the REFERENCE AXIS the location and orientation of determination of the
PERMANENT FILTRATION shall be indicated.
5.3 Indications and statements of FILTERING MATERIALS
If an indication or statement of compliance for FILTERING MATERIALs with this document is to be
given, it shall take the applicable form, as given below, as an example, which applies to a stated
value of 1,2 mm aluminium determined at a HIGH VOLTAGE of 75 kV and a TARGET ANGLE of 12°:
a) for written statements, for example in ACCOMPANYING DOCUMENTS:
FILTERING MATERIAL 1,2 mm Al/75 kV/12° IEC 60522-1:2020
b) for markings on the FILTERING MATERIAL:
1,2 Al/75/12° or 1,2 Al/75/12°

NOTE The symbol for the marking is IEC 60417-5381:2002-10 [1].
In the case of a FILTER with non-uniform thickness or a FILTER which is not oriented
perpendicular to the REFERENCE AXIS, the location and orientation of determination of the
FILTERING MATERIAL shall be indicated.

Annex A
(informative)
Historical background
A.1 General
The purpose of this annex is to describe the history of the document and to elucidate the
reasons behind some difficult parts.
A.2 The first edition of IEC 60522 (1976)
This edition deals with the concept of INHERENT FILTRATION of X-RAY TUBE ASSEMBLIES, its
definition, methods of indication and its determination, and the statement of inherent FILTRATION
measured according to this document.
A.3 The second edition of IEC 60522 (1999)
This edition defines the concept of PERMANENT FILTRATION in X-RAY TUBE ASSEMBLIES for medical
diagnosis and radiotherapy and describes a method for its determination. It contains
requirements for statements of compliance for ACCOMPANYING DOCUMENTS and for markings on
X-RAY TUBE ASSEMBLIES. Methods are given to determine the PERMANENT FILTRATION in an X-RAY
TUBE ASSEMBLY with an accuracy that is sufficient to enable the appropriate ADDITIONAL
FILTRATION to be provided in order to attain the desired TOTAL FILTRATION.
A.4 The first edition of IEC 60522-1 (2020)
The document was separated into two parts IEC 60522-1 and IEC 60522-2, in which -1 is a
replacement for IEC 60522 and IEC TR 60522-2 [2] gives technical and scientific background
of the new methods and procedures of IEC 60522-1.
An overview of the changes and the rationale is given in the Foreword and in the Introduction.

– 18 – IEC 60522-1:2020 © IEC 2020
Bibliography
[1] IEC 60417, Graphical symbols for use on equipment (available at http://www.graphical-
symbols.info/equipment)
[2] IEC TR 60522-2, Medical electrical equipment – Diagnostics X-Rays – Part 2: Guidance
and rationale on quality equivalent filtration and permanent filtration
[3] IEC 60601-2-28:2017, Medical electrical equipment – Part 2-28: Particular requirements
for the basic safety and essential performance of X-ray tube assemblies for medical
diagnosis
_____________
Under preparation. Stage at the time of publication: IEC DECPUB 60522-2:2020.

Index of defined terms
ACCOMPANYING DOCUMENT. IEC 60601-1:2005, 3.4
ADDED FILTER .
...