IEC 60601-2-44:2009/AMD1:2012

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

IEC 60601-2-44:2009/A1:2012
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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

– 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• withdrawn,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.
_____________
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
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
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
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
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.

– 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

60601-2-44 Amend.1 © IEC:2012 – 5 –
201.3.203
COMPUTED TOMOGRAPHY DOSE INDEX 100
CTDI
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
∫
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 evalu
...