SIST EN 60601-2-44:2009/A1:2014

Medical electrical equipment - Part 2-44: Particular requirements for the basic safety and essential performance of X-ray equipment for computed tomography

This International Standard applies to the BASIC SAFETY and ESSENTIAL PERFORMANCE of CT SCANNERS, hereafter also referred to as ME EQUIPMENT. If a clause or subclause is specifically intended to be applicable to ME EQUIPMENT only, or to ME SYSTEMS only, the title and content of that clause or subclause will say so. If that is not the case, the clause or subclause applies both to ME EQUIPMENT and to ME SYSTEMS, as relevant. NOTE 1 See also 4.2 of the general standard. The scope of this document is limited to CT SCANNERS intended to be used for both head and body characterised by an ENCLOSURE of the X-ray source(s) and imaging detector(s) in a common protective cover in the shape of a toroid. It includes safety requirements for the XRAY GENERATORS used in CT SCANNERS, including those where HIGH-VOLTAGE GENERATORS are integrated with an X-RAY TUBE ASSEMBLY. NOTE 2 Requirements for X-RAY GENERATORS and for ASSOCIATED EQUIPMENT, which were previously specified in IEC 60601-2-7 and IEC 60601-2-32, have been included in either IEC 60601-1:2005 (Ed3) or this edition of IEC 60601-2-44. Therefore IEC 60601-2-7 and IEC 60601-2-32 are not part of the 3rd edition scheme for COMPUTED TOMOGRAPHY.

Medizinische elektrische Geräte - Teil 2-44: Besondere Festlegungen für die Sicherheit einschließlich der wesentlichen Leistungsmerkmale von Röntgeneinrichtungen für die Computertomographie

Appareils electromédicaux - Partie 2-44: Exigences particulières pour la sécurité de base et les performances essentielles des équipements à rayonnement X de tomodensitométrie

Medicinska električna oprema - 2-44. del: Posebne zahteve za osnovno varnost in bistvene lastnosti rentgenske opreme za računalniško tomografijo - Dopolnilo A1(IEC 60601-2-44:2009/A1:2012)

Ta mednarodni standard velja za OSNOVNO VARNOST in BISTVENE LASTNOSTI RENTGENOV ZA RAČUNALNIŠKO TOMOGRAFIJO, v nadaljevanju ME OPREMA. Če bo točka ali podtočka izrecno namenjena samo uporabi za ME OPREMO ali samo za ME SISTEME, bosta naslov in vsebina te točke ali podtočke to tudi navedla. Sicer točka in podtočka veljata za ustrezno ME OPREMO in ME SISTEME.  OPOMBA 1: Prav tako glej 4.2 splošnega standarda. Obseg tega dokumenta je omejen na RENTGENE ZA RAČUNALNIŠKO TOMOGRAFIJO, namenjene uporabi na glavi in telesu, za katere je značilno OHIŠJE rentgenskega vira(-ov) in slikovnega detektorja(-ev) v splošnem zaščitnem ohišju v obliki toroida. Vključuje varnostne zahteve RENTGENSKIH GENERATORJEV, ki se uporabljajo pri RENTGENIH ZA RAČUNALNIŠKO TOMOGRAFIJO, vključno s tistimi, kjer so VISOKONAPETOSTNI GENERATORJI vgrajeni v SESTAV RENTGENSKE CEVI. OPOMBA 2: Zahteve za rentgenske GENERATORJE in POVEZANO OPREMO, ki so bili predhodno določeni v IEC 60601-2-7 in IEC 60601-2-32, so bili vključeni v IEC 60601-1:2005 (Ed3) ali v to izdajo IEC 60601-2-44. Zato IEC 60601-2-7 in IEC 60601-2-32 nista del sheme 3. izdaje za RAČUNALNIŠKOTOMOGRAFIJO.

General Information

• Status: Published
• Publication Date: 02-Jan-2014
• ICS: 11.040.50 - Radiographic equipment
• Technical Committee: IEMO - Electrical equipment in medical practice
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 16-Dec-2013
• Due Date: 20-Feb-2014
• Completion Date: 03-Jan-2014
• Directive: 93/42/EEC - Council Directive 93/42/EEC of 14 June 1993 concerning medical devices
• Ref Project: EN 60601-2-44:2009/A1:2012 - Medical electrical equipment - Part 2-44: Particular requirements for the basic safety and essential performance of X-ray equipment for computed tomography

Relations

• Amends: SIST EN 60601-2-44:2009 - Medical electrical equipment - Part 2-44: Particular requirements for basic safety and essential performance of X-ray equipment for computed tomography (IEC 60601-2-44:2009)
• Effective Date: 29-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60601-2-44:2009/A1:2014
01-februar-2014
0HGLFLQVNDHOHNWULþQDRSUHPDGHO3RVHEQH]DKWHYH]DRVQRYQRYDUQRVWLQ
ELVWYHQHODVWQRVWLUHQWJHQVNHRSUHPH]DUDþXQDOQLãNRWRPRJUDILMR'RSROQLOR$
,(&$
Medical electrical equipment - Part 2-44: Particular requirements for the basic safety and
essential performance of X-ray equipment for computed tomography
Medizinische elektrische Geräte - Teil 2-44: Besondere Festlegungen für die Sicherheit
einschließlich der wesentlichen Leistungsmerkmale von Röntgeneinrichtungen für die
Computertomographie
Appareils electromédicaux - Partie 2-44: Exigences particulières pour la sécurité de base
et les performances essentielles des équipements à rayonnement X de
tomodensitométrie
Ta slovenski standard je istoveten z: EN 60601-2-44:2009/A1:2012
ICS:
11.040.50 Radiografska oprema Radiographic equipment
SIST EN 60601-2-44:2009/A1:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60601-2-44:2009/A1:2014

---------------------- Page: 2 ----------------------

SIST EN 60601-2-44:2009/A1:2014

EUROPEAN STANDARD
EN 60601-2-44/A1

NORME EUROPÉENNE
October 2012
EUROPÄISCHE NORM

ICS 11.040.50


English version


Medical electrical equipment -
Part 2-44: Particular requirements for the basic safety and essential
performance of X-ray equipment for computed tomography
(IEC 60601-2-44:2009/A1:2012)


Appareils electromédicaux -  Medizinische elektrische Geräte -
Partie 2-44: Exigences particulières Teil 2-44: Besondere Festlegungen
pour la sécurité de base für die Sicherheit einschließlich
et les performances essentielles der wesentlichen Leistungsmerkmale
des équipements à rayonnement X von Röntgeneinrichtungen
de tomodensitométrie für die Computertomographie
(CEI 60601-2-44:2009/A1:2012) (IEC 60601-2-44:2009/A1:2012)




This amendment A1 modifies the European Standard EN 60601-2-44:2009; it was approved by CENELEC on
2012-10-04. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this amendment 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 amendment 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, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60601-2-44:2009/A1:2012 E

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SIST EN 60601-2-44:2009/A1:2014
EN 60601-2-44:2009/A1:2012 - 2 -
Foreword
The text of document 62B/869/FDIS, future amendment 1 to edition 3 of IEC 60601-2-44, 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 60601-2-44:2009/A1:2012.
The following dates are fixed:
(dop) 2013-07-04
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2015-10-04
standards conflicting with the
document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.

This document has been prepared under a mandate given to CENELEC by the European Commission
and the European Free Trade Association, and supports essential requirements of EU Directive(s).

Endorsement notice
The text of the International Standard IEC 60601-2-44:2009/A1:2012 was approved by CENELEC as
a European Standard without any modification.

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SIST EN 60601-2-44:2009/A1:2014
- 3 - EN 60601-2-44:2009/A1:2012
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year
In Annex ZA of EN 60601-2-44:2009, add under Replacement the following new
reference:
IEC 60601-1-2 2007 Medical electrical equipment - EN 60601-1-2 2007
(mod) Part 1-2: General requirements for basic + corr. March 2010
safety and essential performance - Collateral
standard: Electromagnetic compatibility -
Requirements and tests

In Annex ZA of EN 60601-2-44:2009, add under Addition the following new
reference:
IEC 60336 - Medical electrical equipment - X-ray tube EN 60336 -
assemblies for medical diagnosis -
Characteristics of focal spots

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SIST EN 60601-2-44:2009/A1:2014

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SIST EN 60601-2-44:2009/A1:2014




IEC 60601-2-44

®


Edition 3.0 2012-08




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE
colour

inside



AMENDMENT 1

AMENDEMENT 1





Medical electrical equipment –

Part 2-44: Particular requirements for the basic safety and essential performance

of X-ray equipment for computed tomography




Appareils électromédicaux –

Partie 2-44: Exigences particulières pour la sécurité de base et les performances


essentielles des équipements à rayonnement X de tomodensitométrie













INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX U


ICS 11.040.50 ISBN 978-2-83220-304-0



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 60601-2-44:2009/A1:2014
– 2 – 60601-2-44 Amend.1 © IEC:2012
FOREWORD
This amendment has been prepared by subcommittee SC 62B: Diagnostic imaging equipment,
of IEC Technical Committee 62: Electrical equipment in medical practice.
The text of this amendment is based on the following documents:
FDIS Report on voting
62B/879/FDIS 62B/890/RVD

Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
NOTE The attention of National Committees is drawn to the fact that equipment MANUFACTURERS and testing
organizations may need a transitional period following publication of a new, amended or revised IEC publication in
which to make products in accordance with the new requirements and to equip themselves for conducting new or
revised tests. It is the recommendation of the committee that the content of this publication be adopted for
implementation nationally not earlier than 3 years from the date of publication.

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 60601-2-44:2009/A1:2014
60601-2-44 Amend.1 © IEC:2012 – 3 –
Introduction to Amendment 1
The main topic addressed in this amendment is an extended concept of CTDI to
accommodate CT SCANNERS with very large z-coverage. The other principal subject areas
include:
1) a dose-check feature associated with a pre-scanning alert if expected values of dose
DOSE NOTIFICATION VALUES or DOSE ALERT VALUES and
indices exceed user-configurable
2) requirements covering the use of CT data in radiotherapy treatment planning (RTP).
The CT dose metric in use has been based on the CTDI , i.e. measurement of dose in
100
PHANTOMs and limited integration of scattered radiation, and it is used in many countries’
legislation to define "dose reference values" (also called "diagnostic reference levels") for CT
examinations. Many people use these indices, CTDI and DLP, to derive estimates for
vol
is also part of CT acceptance and constancy
effective dose via conversion factors. CTDI
100
testing. The introduction of a new dose index would change all CT SCANNERS’ CTDI values.
Therefore the intention is to stay with the CTDI , i.e. the integration of primary radiation and
100
scatter over 100 mm, but adapt the way of measuring and reporting the dose index to
incorporate large collimations and to rate all collimations the same way, i.e. to reflect
approximately the same percentage of CTDI for all collimations.
∞
As defined in the amendment, CTDI is to be measured only for collimations up to 40 mm
100
with the current equipment, i.e. the PMMA PHANTOMs and a 100-mm chamber, or other
suitable methods that use a RADIATION DETECTOR. For these collimations there is no significant
change of the ratio CTDI / CTDI according to published data. For larger collimations at
100 ∞
the same CT CONDITIONS OF OPERATION, the z-efficiency may be different and must be
evaluated in the dose measurement. This can be accomplished by the measurement of dose
and the CTDI have been refined. Both
‘free air’. Based on these considerations CTDI
100 free air
types of measurement are combined now to determine the CTDI values for larger collimations
and they are explained in detail in informative Annexes CC and DD.
Some additional requirements and refinements related to dose have been added: CTDI and
vol
DLP are defined for a new type of scan mode (‘shuttle mode’). In body CT EXAMINATION it is
clarified that the CTDI and DLP always be reported for the 32-cm diameter PHANTOM. In the
vol
SCANNERS support user-configurable DOSE NOTIFICATION
amendment it is now required that CT
VALUES and DOSE ALERT VALUES.
A new subject area in this Amendment 1 covers requirements for CT SCANNERS providing
images for radiotherapy treatment planning. With this amendment begins the implementation
of this important CT application into the CT safety standard with a set of requirements that is
considered to be safety relevant. It mainly covers scanner hardware adjustments, accuracy of
CT image data, and the conversion of HU to electron and mass density.

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SIST EN 60601-2-44:2009/A1:2014
– 4 – 60601-2-44 Amend.1 © IEC:2012
201.1.1 Scope
Add the following new sentence:
The scope of this International Standard excludes RADIOTHERAPY SIMULATORS and systems
where the image is created by a source other than an X-RAY TUBE.
201.1.3 Collateral standards
Replace the existing text of this subclause with the following:
Addition:
This particular standard refers to those applicable collateral standards that are listed in
Clause 2 of the general standard and Clause 201.2 of this particular standard.
IEC 60601-1-2 and IEC 60601-1-3 apply as modified in Clauses 202 and 203. IEC 60601-1-8,
1) 2) 3)
IEC 60601-1-9, IEC 60601-1-10 , IEC 60601-1-11 and IEC 60601-1-12 do not apply. All
other published collateral standards in the IEC 60601-1 series apply as published.
For collateral standards published after this particular standard, MANUFACTURERS need to
determine the applicability in accordance with the RISK MANAGEMENT PROCESS.
201.2 Normative references
Add, under "Replacement", the following new reference:
IEC 60601-1-2:2007, Medical electrical equipment – Part 1-2: General requirements for basic
safety and essential performance – Collateral standard: Electromagnetic compatibility –
Requirements and tests
Add, under "Addition", the following new reference:
IEC 60336 Medical electric equipment – X-Ray Tube assemblies for medical diagnosis –
Characteristics of focal spots
201.3 Terms and definitions
201.3.202
CT CONDITIONS OF OPERATION
Add a note 3 to this definition:
NOTE 3 CT CONDITIONS OF OPERATION include parameters that are derived by the system from the user-selectable
parameters.
___________
1)
IEC 60601-1-10, Medical electrical equipment – Part 1-10: General requirements for basic safety and essential
performance – Collateral Standard: Requirements for the development of physiologic closed-loop controllers
2)
 IEC 60601-1-11, Medical electrical equipment – Part 1-11: General requirements for basic safety and essential
performance – Collateral Standard: Requirements for medical electrical equipment and medical electrical
systems used in the home healthcare environment
3)
  IEC 60601-1-12, Medical electrical equipment – Part 1-12: General requirements for basic safety and essential
performance – Collateral Standard: Requirements for medical electrical equipment and medical electrical
systems intended to be used in the emergency medical services environment

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SIST EN 60601-2-44:2009/A1:2014
60601-2-44 Amend.1 © IEC:2012 – 5 –
201.3.203
COMPUTED TOMOGRAPHY DOSE INDEX 100
CTDI
100
Replace the existing text of the definition by the following:
integral of the DOSE PROFILE representative of a single axial scan along a line perpendicular to
the TOMOGRAPHIC PLANE divided by N x T according to the following:
for N × T less than or equal to 40 mm
+50 mm
D (z)

=  dz
CTDI
100
∫
N × T
−50 mm
for N × T greater than 40 mm (all CT CONDITIONS OF OPERATION except collimation are kept the
same for these measurements)
+50 mm
CTDI
D (z)
Ref free air, N×T

=  dz ×
CTDI100
∫
(N ×T) CTDI
Ref free air, Ref
−50 mm
where
D(z) is the DOSE PROFILE representative of a single axial scan along a line z
perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as
ABSORBED DOSE in air and is evaluated within a polymethylmethacrylate
PHANTOM (see 203.108);
(PMMA) dosimetry
(N × T) is a specific N × T of 20 mm or the largest N × T available not greater than
Ref
20 mm;
D (z) is the DOSE PROFILE representative of a single axial scan along a line z
Ref
perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as
ABSORBED DOSE in air and is evaluated within a polymethylmethacrylate
(PMMA) dosimetry PHANTOM (see 203.108) for (N × T) ;
Ref
CTDI is the CTDI (201.3.215) for a specific value of N × T;
free air, N × T free air
CTDI is the CTDI (201.3.215) for (N × T) ;
free air, Ref free air Ref
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of
the X-ray source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS.
NOTE 1 The dose is reported as ABSORBED DOSE to air, but for practical purposes the evaluation of ABSORBED
DOSE to air within a PMMA dosimetry PHANTOM is well approximated by measurement of the AIR KERMA.
NOTE 2 This definition assumes that the DOSE PROFILE is centred on z = 0.
NOTE 3 A single axial scan is typically a 360° rotation of the X-ray source.
NOTE 4 When the TOMOGRAPHIC SECTIONS overlap, e.g. in CT SCANNERS with a “z-flying FOCAL SPOT”, the
denominator of the integral needs to be replaced by the total nominal width along z of overlapping tomographic
sections. For example, if the percentage of overlap is 50%, then the denominator would be replaced by 0,5 × N × T.
NOTE 5 Typically the z-axis is the axis of rotation.
NOTE 6 The CTDI is designed to include most of the scattered radiation.
100
NOTE 7 See Annex CC for explanation.
201.3.204
CT PITCH FACTOR
Replace, in Note 3, the text “or N × T are” by the word “is”.

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SIST EN 60601-2-44:2009/A1:2014
– 6 – 60601-2-44 Amend.1 © IEC:2012
201.3.212
VOLUME CTDI
w
CTDI
vol
a) for axial scanning
Replace Notes 1 and 2 by the following:
NOTE 1 For the selected CT CONDITIONS OF OPERATION, but irrespective of any scanning length that may be used
clinically, the VOLUME CTDI (CTDI ) is an index of dose based on a convention of 100 mm range of integration
w vol
along the z-axis. For axial scanning, CTDI corresponds to the average dose that would accrue in the PHANTOM
vol
central section of volume equal to the cross sectional area × ∆d.
NOTE 2 For axial scanning with a total table travel much less than N × T, CTDI as defined overestimates the
vol
average dose that would accrue in the PHANTOM central section of volume equal to the cross sectional area ×Δd.
b) for helical scanning
In Note 1 replace the text “or N × T are” by the text “is”.
Replace Notes 2 and 3 by the following:
NOTE 2 For the selected CT CONDITIONS OF OPERATION, but irrespective of any scanning length that may be used
clinically, the VOLUME CTDI (CTDI ) is an index of dose based on a convention of 100 mm range of integration
w vol
along the z-axis. For helical scanning, CTDI corresponds to the average dose that would accrue in the centre of
vol
a 100 mm scan length.
NOTE 3 For helical scanning, when the product of a small number of rotations times the table travel per rotation
is much less than N × T, CTDI as defined overestimates the average dose that would accrue in the centre of a
vol
100-mm scan length.
Add the following new item:
d) for axial scanning without gaps and helical scanning, both involving back-and-forth
PATIENT SUPPORT movement between two positions (shuttle mode)
N ×T
CTDI = n CTDI
vol w
(N ×T ) + R
where
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
n is equal to the total number of rotations for the entire scan series;
R is the distance between the two positions;
CTDI is the WEIGHTED CTDI .
W 100
NOTE 1 Seen Figure 201.102.
NOTE 2 CTDI is evaluated as the time weighed CTDI reflecting the varying CT CONDITIONS OF OPERATION.
w w

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SIST EN 60601-2-44:2009/A1:2014
60601-2-44 Amend.1 © IEC:2012 – 7 –

Z
F F
R
I I
N × T
(N × T) + R
IEC  1615/12

F FOCAL SPOT
I ISOCENTRE
Z z-direction
Figure 201.102 – Illustration of N × T,R and (N × T) + R
201.3.214
DOSE-LENGTH PRODUCT
DLP
b) For helical scanning
Replace the existing text:
L is the table travel during the entire LOADING.
by the following new text:
L is the table travel during the entire LOADING, adjusted for dynamic collimation modes if
applicable.
Add the following new note:
NOTE 3 A way for obtaining L could be to use the FWHM along a line perpendicular to the TOMOGRAPHIC PLANE at
isocenter of the free-in-air DOSE PROFILE for the entire scan. In the absence of dynamic collimation this is
approximately equivalent to table travel during the entire LOADING.
Add the following new item:
d) for axial scanning without gaps and helical scanning, both involving back-and-forth
PATIENT SUPPORT movement between two positions (shuttle mode)
DLP = CTDI × ((N ×T) + R)
vol
where
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
R is the distance between the two positions.

201.3.215
COMPUTED TOMOGRAPHY DOSE INDEX FREE-IN-AIR
CTDI
FREE AIR
Replace the existing symbol by the following:
CTDI
free air

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SIST EN 60601-2-44:2009/A1:2014
– 8 – 60601-2-44 Amend.1 © IEC:2012

Replace the existing text of the definition by the following:
integral of the DOSE PROFILE representative of a single axial scan along a line through the
ISOCENTRE and perpendicular to the TOMOGRAPHIC PLANE divided by N × T according to the
following
+L/2
D (z)

=  dz
CTDIfree air
∫
N × T
−L/2
where
D(z) is the DOSE PROFILE representative of a single axial scan along a line z through
ISOCENTRE and perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as
ABSORBED DOSE in air and is evaluated free-in-air in the absence of a PHANTOM and the
PATIENT SUPPORT;
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
L is at least (N × T) +40 mm, but not less than 100 mm.
NOTE 1 This definition assumes that the DOSE PROFILE is centred on z = 0.
NOTE 2 When the TOMOGRAPHIC SECTIONS overlap, e.g. in CT SCANNERS with a “z-flying FOCAL SPOT”, the
denominator of the integral needs to be replaced by the total nominal width along z of overlapping tomographic
sections. For example, if the percentage of overlap is 50 %, then the denominator would be replaced by
0,5 × N × T.
NOTE 3 Typically a RADIATION DETECTOR of length L or longer is used. Annex DD provides an example for
alternate measurements.
Add the following new terms and definitions:
201.3.216
PROTOCOL ELEMENT
set of the particular CT CONDITIONS OF OPERATION necessary to perform a scan
NOTE 1 The following modes are examples of different types of scan: helical, axial, axial series, scanning without
movement of the patient support and shuttle mode.
NOTE 2 To maintain consistency with their respective user interfaces and documentation, various CT SCANNERS
might use terminology different from “PROTOCOL ELEMENT”, e.g., “scan”, “scan group”, “scan series”, etc., which
actually means “PROTOCOL ELEMENT”
NOTE 3 A PROTOCOL ELEMENT is typically associated with a defined clinical task, clinical context, anatomical
region, and/or age or size group. It corresponds to one sequence of scanning in a CT EXAMINATION.
201.3.217
CT EXAMINATION
group of PROTOCOL ELEMENTS used for the entire COMPUTED TOMOGRAPHY PROCEDURE for a
particular PATIENT
201.3.218
DOSE NOTIFICATION VALUE
value of CTDI , CTDI per second, or DLP used to trigger a notification on the control
vol vol
panel
NOTE A DOSE NOTIFICATION VALUE could represent a level of concern associated with a dose index value that
would exceed a value normally expected for the PROTOCOL ELEMENT (e.g. a diagnostic reference level or similar
value determined by the RESPONSIBLE ORGANIZATION).

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201.3.219
DOSE ALERT VALUE
value of CTDI or DLP used to trigger an alert on the control panel
vol
NOTE A DOSE ALERT VALUE could represent a level of concern (e.g. avoidance of deterministic effects) higher than
that of a DOSE NOTIFICATION VALUE, and it would therefore warrant more stringent review and consideration before
proceeding.”
201.4 General requirements
201.4.3 ESSENTIAL PERFORMANCE
Replace the existing text of this subclause with the following:
Addition:
For CT SCANNERS for which the INTENDED USE includes COMPUTED TOMOGRAPHY as the
principal means of guidance in invasive procedures (e.g., involving the introduction of a
device, such as a needle or a catheter into the body of the PATIENT), any ESSENTIAL
aspects related to such use shall be identified in the ACCOMPANYING DOCUMENTS
PERFORMANCE
and in the RISK MANAGEMENT FILE.
NOTE An example of what would not be considered ESSENTIAL PERFORMANCE is the extraction of needles where
images are not required for guidance.
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS and the RISK
MANAGEMENT FILE.
201.7.9.101 Reference to ACCOMPANYING DOCUMENTS
Replace the following line:
– LIGHT FIELD 203.115
by the following new line:
– Light marker 203.115 c)
Add the following new lines:
– ESSENTIAL PERFORMANCE 201.4.3
– Alignment of the top of the PATIENT SUPPORT 201.101.2
– Top of the PATIENT SUPPORT 201.101.3
– Table sag (stiffness of the PATIENT SUPPORT) 201.101.4
– Integral light markers for PATIENT marking 201.101.5
– Typical scan mode to provide images for RTP 201.101.6
– HU-value conversion 201.101.7
– Geometric accuracy of image data 201.101.8
– Information in the ACCOMPANYING DOCUMENTS 203.10.2
– Display and recording of CTDI and DLP 203.112
vol
201.8.8.3 Dielectric strength
Replace the existing third paragraph with the following:

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If the HIGH-VOLTAGE GENERATOR can only be tested with the X-RAY TUBE connected, the test
voltage may be lower but shall not be less than 1,1 times the NOMINAL X-RAY TUBE VOLTAGE of
the HIGH-VOLTAGE GENERATOR or X-RAY TUBE ASSEMBLY ( whichever is lower).
NOTE 101 For the NOMINAL X-RAY TUBE VOLTAGE of the HIGH-VOLTAGE GENERATOR, see also subclause 201.8.4.101,
Limitation of high voltage to the NOMINAL X-RAY TUBE VOLTAGE.
201.9.2.4.101.3 Linear movements of the PATIENT SUPPORT and gantry
In the last sentence of the first paragraph replace "25 mm after actuation" with "50 mm after
actuation".
Add the following two new paragraphs after the existing first paragraph:
If a scan mode is selected in which the PATIENT SUPPORT cannot stop within 25 mm after
actuation of the emergency stop, before the scan is initiated the CT SCANNER shall display an
alert on the CONTROL PANEL regarding this situation and instruct the OPERATOR to ensure the
PATIENT area of travel is free from obstruction.
The ACCOMPANYING DOCUMENTS shall identify the scan modes that cannot meet the 25 mm
emergency stop distance.
Replace the existing compliance statement by:
Compliance is checked by functional test and inspection of the ACCOMPANYING DOCUMENTS.
201.12.1.102 Accuracy of recorded CT EXAMINATION data
Replace existing item a)by the following:
a) When a RADIOGRAM for preview (as described in 203.115 of this particular standard) is
provided, the position of the TOMOGRAPHIC SECTIONS shall be clearly indicated on the
RADIOGRAM.
The indication of the position of the TOMOGRAPHIC SECTIONS shall be accurate within
± 2 mm.
Add the following additional clauses:
201.101 Requirements for CT SCANNERS providing images for RADIOTHERAPY
TREATMENT PLANNING (RTP)
201.101.1 General
Clause 201.101 applies only to CT SCANNERS whose INTENDED USE includes providing image
data for RADIOTHERAPY TREATMENT PLANNING (RTP).
Requirements related to the CT SCANNER (gantry, PATIENT SUPPORT, light markers) and
conversion of Hounsfield Units to electron and mass density are addressed.
201.101.2 Alignment of the top of the PATIENT SUPPORT
201.101.2.1 General
The ACCOMPANYING DOCUMENTS shall describe the procedures for aligning the top of the
PATIENT SUPPORT with respect to the TOMOGRAPHIC PLANE such that the long axis of the top of
the PATIENT SUPPORT is aligned vertically and horizontally over the maximum scan range along
the z direction.

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Compliance of the alignment requirements in subclauses 201.101.2.2 and 201.101.2.3 is
checked by inspection of the ACCOMPANYING DOCUMENTS.
201.101.2.2 Alignment of the PATIENT SUPPORT in the vertical plane (tilt)
The alignment procedure shall require the accuracy of the alignment to be ±0,5º or less with
respect to the horizontal plane (Figure 201.103).
The alignment procedure shall require this measurement to be taken on the retracted top of
the PATIENT SUPPORT, without load, after installation.
Y
Z′
t
Z
1 2
IEC  1616/12

Z Z-axis
Z’ Axis of the top of the PATIENT SUPPORT
t Tilt angle
1 Gantry
2 PATIENT SUPPORT
Figure 201.103 – Vertical alignment of the PATIENT SUPPORT
201.101.2.3 Alignment of the PATIENT SUPPORT in the horizontal plane
a) The alignment procedure shall require the axis of the horizontal movement of the top of
the PATIENT SUPPORT to be perpendicular to the x-axis of the TOMOGRAPHIC PLANE within
± 1º.
b) The alignment procedure shall require the centerline of the top of the PATIENT SUPPORT to
be marked at the front end (M1) and at a distance of 1 m from the front end (M2). The
difference between the centerline and the z-axis indicated by the sagittal light marker shall
be measured at the position of the scan plane for both M1 and M2. Neither d1
...