EN IEC 60336:2021

Medical electrical equipment - X-ray tube assemblies for medical diagnosis - Focal spot dimensions and related characteristics

IEC 60336:2020 applies to FOCAL SPOTS in medical diagnostic X-RAY TUBE ASSEMBLIES for medical use, operating at X-RAY TUBE VOLTAGES up to and including 150 kV. This document describes the test methods employing digital detectors for determining: a) FOCAL SPOT dimensions in terms of NOMINAL FOCAL SPOT VALUES, ranging from 0,1 to 3,0; b) LINE SPREAD FUNCTIONS; c) one-dimensional MODULATION TRANSFER FUNCTIONS; d) FOCAL SPOT PINHOLE RADIOGRAMS, and the means for indicating compliance. In informative annexes, STAR PATTERN imaging and BLOOMING VALUE are described. IEC 60336:2020 cancels and replaces the fourth edition published in 2005. This edition constitutes a technical revision. The significant changes of this fifth edition with respect to the previous edition are detailed in Clause E.6. These changes are: a) introduction of digital detectors and discretization errors; b) fewer normative requirements; c) support for both SLIT CAMERA and PINHOLE CAMERA; d) reintroduction of distorted (skewed) FOCAL SPOT; e) keeping of STAR PATTERNS and BLOOMING VALUE as informative.

Medizinische elektrische Geräte - Röntgenstrahler für medizinische Diagnostik - Kennwerte von Brennflecken

Appareils électromédicaux - Gaines équipées pour diagnostic médical - Dimensions des foyers et caractéristiques connexes

L'IEC 60336:2020 s’applique aux FOYERS des GAINES EQUIPEES à usage médical, pour diagnostic médical, fonctionnant à des POTENTIELS D’ACCELERATION DE TUBES RADIOGENES inférieurs ou égaux à 150 kV. Le présent document décrit les méthodes d’essai ayant recours à des détecteurs numériques dans la détermination des: a) dimensions des FOYERS en matière de VALEURS NOMINALES DE FOYER, variant de 0,1 à 3,0; b) FONCTIONS DE DISTRIBUTION LINEAIRE; c) FONCTIONS DE TRANSFERT DE MODULATION suivant une dimension; d) RADIOGRAMMES A STENOPE, et des moyens d’indiquer la conformité. Les annexes informatives décrivent la MIRE ETOILE et la VALEUR DE DISPERSION. L'IEC 60336:2020 annule et remplace la quatrième édition parue en 2005. Cette édition constitue une révision technique. Les modifications majeures présentées dans cette cinquième édition par rapport à l’édition précédente sont énumérées dans l’Article E.6. Ces modifications sont: a) introduction des détecteurs numériques et des erreurs de discrétisation; b) exigences normatives moins nombreuses; c) informations d’accompagnement relatives aux CAMERAS A FENTE et aux CAMERAS A STENOPE; d) réintroduction de FOYER déformé (non linéaire); e) conservation des MIRES ETOILES et de la VALEUR DE DISPERSION comme documents informatifs.

Medicinska električna oprema - Rentgenske naprave za medicinsko diagnostiko - Mere žariščnih točk in s tem povezane značilnosti (IEC 60336:2020)

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN IEC 60336:2021
01-april-2021
Nadomešča:
SIST EN 60336:2006
Medicinska električna oprema - Rentgenske naprave za medicinsko diagnostiko -
Mere žariščnih točk in s tem povezane značilnosti (IEC 60336:2020)

Medical electrical equipment - X-ray tube assemblies for medical diagnosis - Focal spot

dimensions and related characteristics (IEC 60336:2020)
Medizinische elektrische Geräte - Röntgenstrahler für medizinische Diagnostik -
Kennwerte von Brennflecken (IEC 60336:2020)

Appareils électromédicaux - Gaines équipées pour diagnostic médical - Dimensions des

foyers et caractéristiques connexes (IEC 60336:2020)
Ta slovenski standard je istoveten z: EN IEC 60336:2021
ICS:
11.040.50 Radiografska oprema Radiographic equipment
11.040.55 Diagnostična oprema Diagnostic equipment
SIST EN IEC 60336:2021 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 60336:2021
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SIST EN IEC 60336:2021
EUROPEAN STANDARD EN IEC 60336
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2021
ICS 11.040.50 Supersedes EN 60336:2005 and all of its amendments
and corrigenda (if any)
English Version
Medical electrical equipment - X-ray tube assemblies for medical
diagnosis - Focal spot dimensions and related characteristics
(IEC 60336:2020)

Appareils électromédicaux - Gaines équipées pour Medizinische elektrische Geräte - Röntgenstrahler für

diagnostic médical - Dimensions des foyers et medizinische Diagnostik - Kennwerte von Brennflecken

caractéristiques connexes (IEC 60336:2020)
(IEC 60336:2020)

This European Standard was approved by CENELEC on 2021-01-21. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60336:2021 E
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SIST EN IEC 60336:2021
EN IEC 60336:2021 (E)
European foreword

The text of document 62B/1138/CDV, future edition 5 of IEC 60336, prepared by SC 62B "Diagnostic

imaging equipment" of IEC/TC 62 "Electrical equipment in medical practice" was submitted to the IEC-

CENELEC parallel vote and approved by CENELEC as EN IEC 60336:2021.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2021-10-21

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2024-01-21

document have to be withdrawn

This document supersedes EN 60336:2005 and all of its amendments and corrigenda (if any).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice

The text of the International Standard IEC 60336:2020 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards

indicated:
IEC 60601-2-28:2017 NOTE Harmonized as EN IEC 60601-2-28:2019 (not modified)
IEC 60336:2005 NOTE Harmonized as EN 60336:2005 (not modified)
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SIST EN IEC 60336:2021
EN IEC 60336:2021 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the

relevant EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available

here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60417 - Graphical symbols for use on equipment. - -
Index, survey and compilation of the single
sheets.
IEC 60601-1 2005 Medical electrical equipment - Part 1: EN 60601-1 2006
General requirements for basic safety and
essential performance
- - + corrigendum Mar. 2010
+ A1 2012 + A1 2013
- - + A12 2014
IEC 60601-1-3 2008 Medical electrical equipment - Part 1-3: EN 60601-1-3 2008
General requirements for basic safety and
essential performance - Collateral
Standard: Radiation protection in
diagnostic X-ray equipment
- - + corrigendum Mar. 2010
+ A1 2013 + A1 2013
- - + AC 2014
- - + A11 2016
IEC 60613 2010 Electrical and loading characteristics of X- EN 60613 2010
ray tube assemblies for medical diagnosis
IEC/TR 60788 2004 Medical electrical equipment - Glossary of - -
defined terms
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SIST EN IEC 60336:2021
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SIST EN IEC 60336:2021
IEC 60336
Edition 5.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Medical electrical equipment – X-ray tube assemblies for medical diagnosis –
Focal spot dimensions and related characteristics
Appareils électromédicaux – Gaines équipées pour diagnostic médical –
Dimensions des foyers et caractéristiques connexes
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 11.040.50 ISBN 978-2-8322-9162-7

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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SIST EN IEC 60336:2021
– 2 – IEC 60336:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 5

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Determinations for the evaluation of the FOCAL SPOT characteristics ................................. 9

4.1 Statement of the FOCAL SPOT characteristics ............................................................ 9

4.2 Longitudinal axis of the X-RAY TUBE ASSEMBLY ......................................................... 9

4.3 REFERENCE AXIS of the X-RAY TUBE ASSEMBLY .......................................................... 9

4.4 Direction of evaluation for the FOCAL SPOT length .................................................... 9

4.5 Direction of evaluation for the FOCAL SPOT width .................................................... 10

4.6 Directions of evaluation for distorted FOCAL SPOTS................................................. 10

5 FOCAL SPOT camera set-up ............................................................................................. 10

5.1 Overview............................................................................................................... 10

5.2 Diaphragm of the SLIT CAMERA ............................................................................... 10

5.3 Diaphragm of the PINHOLE CAMERA......................................................................... 11

5.4 Receptor ............................................................................................................... 12

5.5 Test arrangement .................................................................................................. 12

5.5.1 Position of the slit or pinhole diaphragm normal to the REFERENCE AXIS .......... 12

5.5.2 Position of the slit or pinhole diaphragm along the REFERENCE AXIS ................ 13

5.5.3 Orientation of the slit or pinhole diaphragm .................................................... 14

5.5.4 Position and orientation of the receptor of the DIGITAL FOCAL SPOT

DETECTOR....................................................................................................... 14

5.6 Total uncertainty of the camera set-up .................................................................. 15

6 Production of RADIOGRAMS ............................................................................................. 16

6.1 Overview............................................................................................................... 16

6.2 Operating conditions ............................................................................................. 16

6.2.1 X-RAY TUBE ASSEMBLY ..................................................................................... 16

6.2.2 LOADING FACTORS ........................................................................................... 16

6.2.3 Special LOADING FACTORS ............................................................................... 17

6.2.4 Special arrangements .................................................................................... 17

6.3 Production of FOCAL SPOT SLIT RADIOGRAMS, FOCAL SPOT PINHOLE RADIOGRAMS

and FOCAL SPOT LINE SPREAD FUNCTIONS ................................................................ 17

6.3.1 DIGITAL FOCAL SPOT DETECTOR requirements for FOCAL SPOT SLIT

RADIOGRAMS ................................................................................................... 17

6.3.2 DIGITAL FOCAL SPOT DETECTOR requirements for FOCAL SPOT PINHOLE

RADIOGRAMS ................................................................................................... 17

6.3.3 Determination of the RADIOGRAMS and of the LINE SPREAD FUNCTIONS ............. 18

6.4 Statement of compliance of the FOCAL SPOT PINHOLE RADIOGRAM............................ 18

6.5 Statement of compliance of LINE SPREAD FUNCTIONS .............................................. 18

7 Determination of FOCAL SPOT dimensions and NOMINAL FOCAL SPOT VALUES .................... 19

7.1 Overview............................................................................................................... 19

7.2 Measurement and determination of FOCAL SPOT dimensions .................................. 19

7.3 Specified NOMINAL FOCAL SPOT VALUEs ................................................................... 19

7.3.1 Nominal values .............................................................................................. 19

7.3.2 Actual dimensions ......................................................................................... 20

7.4 Statement of compliance ....................................................................................... 21

7.5 Marking of compliance .......................................................................................... 21

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IEC 60336:2020 © IEC 2020 – 3 –

8 Determination of the MODULATION TRANSFER FUNCTION .................................................... 22

8.1 Overview............................................................................................................... 22

8.2 Calculation and presentation of the MODULATION TRANSFER FUNCTION ..................... 22

8.3 Statement of compliance ....................................................................................... 22

9 Alternative measurement methods for determining NOMINAL FOCAL SPOT VALUES ............. 23

Annex A (informative) Alignment to the REFERENCE AXIS ....................................................... 24

Annex B (informative) FOCAL SPOT STAR RADIOGRAM ............................................................. 26

B.1 Overview............................................................................................................... 26

B.2 Test EQUIPMENT ..................................................................................................... 26

B.2.1 STAR PATTERN CAMERA .................................................................................... 26

B.2.2 RADIOGRAPHIC FILM ......................................................................................... 27

B.2.3 Position of the STAR PATTERN CAMERA normal to the REFERENCE AXIS .............. 27

B.2.4 Position of the STAR PATTERN CAMERA in REFERENCE DIRECTION ....................... 27

B.2.5 Alignment of the STAR PATTERN CAMERA .......................................................... 27

B.2.6 Position of the RADIOGRAPHIC FILM .................................................................. 28

B.2.7 Operating conditions ...................................................................................... 28

B.2.8 Production of the FOCAL SPOT STAR RADIOGRAM ............................................... 28

Annex C (informative) STAR PATTERN RESOLUTION LIMIT ......................................................... 29

C.1 Overview............................................................................................................... 29

C.2 Measurement ........................................................................................................ 29

C.3 Determination of the STAR PATTERN RESOLUTION LIMIT ............................................. 30

C.3.1 Determination of the magnification ................................................................. 30

C.3.2 STAR PATTERN RESOLUTION LIMIT for standard magnification ............................ 30

C.3.3 STAR PATTERN RESOLUTION LIMIT for finite magnification .................................. 30

C.3.4 Presentation of STAR PATTERN RESOLUTION LIMIT ............................................. 31

Annex D (informative) BLOOMING VALUE ................................................................................ 32

D.1 Overview............................................................................................................... 32

D.2 Determination of the BLOOMING VALUE .................................................................... 32

Annex E (informative) Historical background ........................................................................ 33

E.1 Overview............................................................................................................... 33

E.2 First edition (1970) ................................................................................................ 33

E.3 Second edition (1982) ........................................................................................... 33

E.4 Third edition (1993) ............................................................................................... 33

E.5 Fourth edition (2005) ............................................................................................ 36

E.6 Fifth edition (2020) ................................................................................................ 37

E.6.1 Overview ....................................................................................................... 37

E.6.2 Fifth edition technical details ......................................................................... 37

Bibliography .......................................................................................................................... 42

Index of defined terms .......................................................................................................... 43

Figure 1 – Directions of evaluation over distorted FOCAL SPOTS ............................................. 10

Figure 2 – Essential dimensions of the slit diaphragm ........................................................... 11

Figure 3 – Essential dimensions of the pinhole diaphragm .................................................... 12

Figure 4 – Position of the centre of the slit or pinhole diaphragm (marked as x in the

figure) with respect to the REFERENCE AXIS ............................................................................ 13

Figure 5 – Reference dimensions and planes ........................................................................ 14

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SIST EN IEC 60336:2021
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Figure 6 – Alignment of the receptor of the DIGITAL FOCAL SPOT DETECTOR with respect

to the slit diaphragm ............................................................................................................. 15

Figure 7 – LINE SPREAD FUNCTION .......................................................................................... 19

Figure 8 – Graphical symbols – FOCAL SPOTS ........................................................................ 21

Figure A.1 – REFERENCE AXIS and directions of evaluation ..................................................... 24

Figure A.2 – PROJECTION of the ACTUAL FOCAL SPOT on the IMAGE RECEPTION PLANE ............... 25

Figure B.1 – Essential dimensions of the star test pattern ..................................................... 26

Figure B.2 – Alignment of the STAR PATTERN CAMERA ............................................................. 27

Figure C.1 – Illustration of the zones of minimum modulation ................................................ 29

Figure E.1 – LSFs for a typical X-RAY TUBE with small FOCAL SPOT (< 0,3 mm) ....................... 34

Figure E.2 – LSFs for a typical X-RAY TUBE with large FOCAL SPOT (≥ 0,3 mm) ....................... 35

Figure E.3 – Corresponding MTFs for the LSFs in Figure E.2................................................ 35

Figure E.4 – Percentage error of 15 % width ......................................................................... 38

Figure E.5 – Percentage error of LINE SPREAD FUNCTION width at 15 % .................................. 39

Figure E.6 – Influence of the direction of evaluation on MTF-quality and on LINE SPREAD

width at 15 % ......................................................................................................... 40

FUNCTION
RADIOGRAMS ......................................................... 15
Table 1 – Recommended enlargement for

Table 2 – LOADING FACTORS................................................................................................... 16

Table 3 – Maximum permissible values of FOCAL SPOT dimensions for NOMINAL FOCAL

SPOT VALUES .......................................................................................................................... 20

Table C.1 – Standard magnifications for STAR PATTERN RESOLUTION LIMIT .............................. 30

Table D.1 – LOADING FACTORS for the determination of the BLOOMING VALUE .......................... 32

Table E.1 – Methods for evaluation of specific aspects characterising the FOCAL SPOT .......... 37

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SIST EN IEC 60336:2021
IEC 60336:2020 © IEC 2020 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –
X-RAY TUBE ASSEMBLIES FOR MEDICAL DIAGNOSIS –
FOCAL SPOT DIMENSIONS AND RELATED CHARACTERISTICS
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,

Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their

preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with

may participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

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assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60336 has been prepared by subcommittee 62B: Diagnostic imaging

equipment, of IEC technical committee 62: Electrical equipment in medical practice.

This fifth edition cancels and replaces the fourth edition published in 2005. This edition

constitutes a technical revision.

The significant changes of this fifth edition with respect to the previous edition are detailed in

Clause E.6. These changes are:
a) introduction of digital detectors and discretization errors;
b) fewer normative requirements;
SLIT CAMERA and PINHOLE CAMERA;
c) support for both
d) reintroduction of distorted (skewed) FOCAL SPOT;
STAR PATTERNS and BLOOMING VALUE as informative.
e) keeping of
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SIST EN IEC 60336:2021
– 6 – IEC 60336:2020 © IEC 2020
The text of this document is based on the following documents:
CDV Report on voting
62B/1138/CDV 62B/1181/RVC

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.

In this document, the following print types are used:
– requirements and definitions: roman type;

– informative material appearing outside of tables, such as notes, examples and references: in smaller type.

Normative text of tables is also in a smaller type;
– TERMS DEFINED IN CLAUSE 3 OF THIS DOCUMENT OR AS NOTED: 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it

contains colours which are considered to be useful for the correct understanding of its

contents. Users should therefore print this document using a colour printer.
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SIST EN IEC 60336:2021
IEC 60336:2020 © IEC 2020 – 7 –
MEDICAL ELECTRICAL EQUIPMENT –
X-RAY TUBE ASSEMBLIES FOR MEDICAL DIAGNOSIS –
FOCAL SPOT DIMENSIONS AND RELATED CHARACTERISTICS
1 Scope

This document applies to FOCAL SPOTS in medical diagnostic X-RAY TUBE ASSEMBLIES for medical

use, operating at X-RAY TUBE VOLTAGES up to and including 150 kV.

This document describes the test methods employing digital detectors for determining:

a) FOCAL SPOT dimensions in terms of NOMINAL FOCAL SPOT VALUES, ranging from 0,1 to 3,0;

b) LINE SPREAD FUNCTIONS;
c) one-dimensional MODULATION TRANSFER FUNCTIONS;
d) FOCAL SPOT PINHOLE RADIOGRAMS,
and the means for indicating compliance.
In informative annexes, STAR PATTERN imaging and BLOOMING VALUE are described.
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 60601-1-3:2008, 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 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
3 Terms and definitions

For the purposes of this document, terms and definitions given in IEC TR 60788:2004,

IEC 60613:2010, IEC 60601-1:2005 and IEC 60601-1:2005/AMD1:2012, IEC 60601-1-3:2008

and IEC 60601-1-3:2008/AMD1:2013 and the following apply.
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SIST EN IEC 60336:2021
– 8 – IEC 60336:2020 © IEC 2020

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
ACTUAL FOCAL SPOT

area on the surface of the TARGET that intercepts the beam of accelerated particles

Note 1 to entry: Regarding accelerated particles, only the intended primary beam is included.

3.2
BLOOMING VALUE
ratio of two resolution limits obtained under specific LOADING conditions

Note 1 to entry: The BLOOMING VALUE is a characteristic of the EFFECTIVE FOCAL SPOT of an X-RAY TUBE.

3.3
DIGITAL FOCAL SPOT DETECTOR

pixel-array device applied to FOCAL SPOT analysis of X-RAY TUBE ASSEMBLIES, providing a digital

output value per pixel which is linearly related to the input X-ray intensity
3.4
EFFECTIVE FOCAL SPOT
FOCAL SPOT
perpendicular PROJECTION of the ACTUAL FOCAL SPOT on the REFERENCE PLANE
3.5
FOCAL SPOT PINHOLE RADIOGRAM

RADIOGRAM obtained by means of a PINHOLE CAMERA, showing the shape and orientation of an

EFFECTIVE FOCAL SPOT, and the spatial distribution of intensity of radiation across it

3.6
FOCAL SPOT SLIT RADIOGRAM

RADIOGRAM obtained by means of a SLIT CAMERA, showing the distribution, across an EFFECTIVE

FOCAL SPOT, in the direction normal to the
...