IEC 60601-2-44:2001

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

Applies to X-ray equipment for computed tomography (CT scanners). Includes safety requirements for the X-ray generator, and those where high voltage generators are integrated with an X-ray tube assembly. Specify methods for demonstrating compliance with those requirements for CT scanners.

General Information

• Status: Published
• Publication Date: 14-Nov-2002
• ICS: 11.040.50 - Radiographic equipment
• Technical Committee: SC 62B - Medical imaging equipment, software, and systems
• Current Stage: DELPUB - Deleted Publication
• Start Date: 25-Feb-2009
• Completion Date: 26-Oct-2025

Relations

• Amended By: IEC 60601-2-44:2001/AMD1:2002 - Amendment 1 - Medical electrical equipment - Part 2-44: Particular requirements for the safety of X-ray equipment for computed tomography
• Effective Date: 05-Sep-2023
• Corrected By: IEC 60601-2-44:2001/COR1:2006 - Corrigendum 1 - Medical electrical equipment - Part 2-44: Particular requirements for the safety of X-ray equipment for computed tomography
• Effective Date: 05-Sep-2023
• Revised: IEC 60601-2-44:2009 - Medical electrical equipment - Part 2-44: Particular requirements for the basic safety and essential performance of X-ray equipment for computed tomography
• Effective Date: 05-Sep-2023
• Revises: IEC 60601-2-44:1999 - Medical electrical equipment - Part 2-44: Particular requirements for the safety of X-ray equipment for computed tomography
• Effective Date: 05-Sep-2023

Overview

IEC 60601-2-44:2001 is a Particular Standard of the IEC 60601 series that addresses the safety of X‑ray equipment for computed tomography (CT scanners). It supplements the General Standard (IEC 60601‑1) and specifies particular safety requirements and test methods for CT X‑ray generators, including cases where high‑voltage generators are integrated with X‑ray tube assemblies. The standard focuses on electrical, mechanical and radiological safety and on methods for demonstrating compliance.

Key topics and requirements

• Scope and object: Applies specifically to X‑ray equipment for computed tomography; establishes requirements necessary for safety and specifies compliance demonstration methods.
• Electrical safety: Requirements for protection against electric shock, including limitation of voltage/energy, enclosure/protective covers, leakage currents and dielectric strength testing.
• Radiation protection: Controls and tests for X‑radiation output, accuracy, reproducibility, linearity and constancy where relevant to patient and operator safety; references radiological protection principles (ICRP).
• Mechanical and thermal safety: Protection against moving parts, excessive temperatures and other constructional hazards.
• Electromagnetic compatibility (EMC): Collateral requirements to manage EMC in diagnostic imaging equipment.
• Operational accuracy and hazardous output: Accuracy of operating data, radiation output accuracy and protection against hazardous outputs from abnormal operation or fault conditions.
• Testing and verification: Defines test methods, loading‑factors for representative tests (informative Annex BB), tables (e.g., half‑value layers for CT) and normative terminology (Annex AA).
• Documentation and marking: Requirements for identification, marking, indicator lights and accompanying documents for safe use and maintenance.

Applications and who uses this standard

• Manufacturers and design engineers: Use IEC 60601‑2‑44 to design CT scanners that meet international safety criteria and to prepare technical documentation for conformity assessment.
• Test laboratories and certification bodies: Apply the standard’s test methods and acceptance criteria during type testing and certification of CT equipment.
• Clinical physicists and hospital biomedical engineers: Reference the standard when performing acceptance testing, commissioning and periodic QA to ensure safe radiation output and electrical performance.
• Regulatory authorities and procurement teams: Use the standard as a benchmark for regulatory compliance, product approval and purchasing specifications.

Related standards

• IEC 60601‑1 (General requirements for medical electrical equipment)
• IEC 60601‑1‑2 (EMC)
• IEC 60601‑1‑3 (Radiation protection in diagnostic X‑ray equipment)
• IEC 60601‑2‑28, IEC 60664‑1, IEC 60788 and ISO 2092 (listed as related in the standard)

Keywords: IEC 60601‑2‑44, CT scanner safety, X‑ray equipment standard, medical electrical equipment, high‑voltage generator, radiological protection, compliance testing, medical device safety.

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
60601-2-44
Second edition
2001-06
Medical electrical equipment –
Part 2-44:
Particular requirements for the safety of
X-ray equipment for computed tomography
Appareils électromédicaux –
Partie 2-44:
Règles particulières de sécurité pour les équipements
à rayonnement X de tomodensitométrie

Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.

Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,

edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the
base publication incorporating amendment 1 and the base publication incorporating
amendments 1 and 2.
Further information on IEC publications
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology. Information relating to
this publication, including its validity, is available in the IEC Catalogue of
publications (see below) in addition to new editions, amendments and corrigenda.
Information on the subjects under consideration and work in progress undertaken
by the technical committee which has prepared this publication, as well as the list
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INTERNATIONAL IEC
STANDARD
60601-2-44
Second edition
2001-06
Medical electrical equipment –
Part 2-44:
Particular requirements for the safety of
X-ray equipment for computed tomography
Appareils électromédicaux –
Partie 2-44:
Règles particulières de sécurité pour les équipements
à rayonnement X de tomodensitométrie

 IEC 2001  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http://www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
V
International Electrotechnical Commission
For price, see current catalogue

– 2 – 60601-2-44 IEC:2001(E)

CONTENTS
FOREWORD 4
..........................................................................................................................

SECTION 1: GENERAL
1 Scope and object 6
.............................................................................................................

1.1 Scope 6
.....................................................................................................................

1.2 Object 6
....................................................................................................................
1.3 Particular Standards 7
...............................................................................................
2 Terminology and definitions 8
.............................................................................................
3 General requirements 10
....................................................................................................
5 Classification 10
.................................................................................................................
6 Identification, marking and documents 11
...........................................................................
6.1 Marking on the outside of EQUIPMENT or EQUIPMENT parts 11
......................................
6.7 Indicator lights and push-buttons 11
..........................................................................
6.8 ACCOMPANYING DOCUMENTS 12
...................................................................................
SECTION 2: ENVIRONMENTAL CONDITIONS
10 Environmental conditions 13
...............................................................................................
SECTION 3: PROTECTION AGAINST ELECTRIC SHOCK HAZARDS
15 Limitation of voltage and/or energy 14
.................................................................................
16 ENCLOSURES and PROTECTIVE COVERS 14
............................................................................
19 Continuous LEAKAGE CURRENTS and PATIENT AUXILIARY CURRENTS 15
...................................
19.3 Allowable values 15
...................................................................................................
20 Dielectric strength 15
..........................................................................................................
20.3 Values of test voltages 15
..........................................................................................
20.4 Tests 16
....................................................................................................................
SECTION 4: PROTECTION AGAINST MECHANICAL HAZARDS
22 Moving parts 17
..................................................................................................................

27 Pneumatic and hydraulic power 18
......................................................................................
SECTION 5: PROTECTION AGAINST HAZARDS FROM UNWANTED OR
EXCESSIVE RADIATION
29 X-RADIATION 19
...................................................................................................................
36 Electromagnetic compatibility 26
.........................................................................................

60601-2-44 © IEC:2001(E) – 3 –

SECTION 6: PROTECTION AGAINST HAZARDS OF IGNITION OF

FLAMMABLE ANAESTHETIC MIXTURES

SECTION 7: PROTECTION AGAINST EXCESSIVE TEMPERATURES AND

OTHER SAFETY HAZARDS
42 Excessive temperatures 26
.................................................................................................

SECTION 8: ACCURACY OF OPERATING DATA AND PROTECTION
AGAINST HAZARDOUS OUTPUT
50 Accuracy of operating data 27
.............................................................................................
50.101 Accuracy of radiation output 27
..............................................................................
50.102 Accuracy of recorded examination data 27
.............................................................
51 Protection against hazardous output 28
..............................................................................
SECTION 9: ABNORMAL OPERATION AND FAULT CONDITIONS;
ENVIRONMENTAL TESTS
SECTION 10: CONSTRUCTIONAL REQUIREMENTS
56 Components and general assembly 28
................................................................................
56.7 Batteries 29
...............................................................................................................
57 MAINS PARTS, components and layout 29
.............................................................................
57.10 CREEPAGE DISTANCES and AIR CLEARANCES 29
..........................................................
Tables
101 HALF-VALUE LAYERS in CT SCANNERS 24
..............................................................................
Figures
101 Coordinate system 9
...........................................................................................................
Annex AA (normative) Terminology – Index of defined terms 30
...............................................
Annex BB (informative) Choosing LOADING FACTORS for tests 33
..............................................
Bibliography 34
.........................................................................................................................

– 4 – 60601-2-44 IEC:2001(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
MEDICAL ELECTRICAL EQUIPMENT –

Part 2-44: Particular requirements for the safety of

X-ray equipment for computed tomography

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60601-2-44 has been prepared by subcommittee 62B: Diagnostic
imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice.
This second edition cancels and replaces the first edition published in 1999 and constitutes a
technical revision.
The text of this Particular Standard is based on the following documents:
FDIS Report of voting
62B/426/FDIS 62B/437/RVD
Full information on the voting for the approval of this standard can be found in the report of
voting indicated in the above table.
Annex AA forms an integral part of this standard.
Annex BB is for information only.

60601-2-44 © IEC:2001(E) – 5 –

In this standard, the following print types are used:

– requirements, compliance with which can be tested and definitions: roman type:

– explanations, advice, notes, general statements and exceptions: smaller type;

– test specifications and headings of subclauses: italic type;

– TERMS DEFINED IN CLAUSE 2 OF THE GENERAL STANDARD OR IN IEC 60788: SMALL CAPITALS.

The committee has decided that the contents of this publication will remain unchanged until

2002-12. At this date, the publication will be

• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
The contents of the corrigendum of April 2006 have been included in this copy.

– 6 – 60601-2-44 IEC:2001(E)

MEDICAL ELECTRICAL EQUIPMENT –

Part 2-44: Particular requirements for the safety of

X-ray equipment for computed tomography

SECTION 1: GENERAL
The clauses and subclauses of this section of the General Standard apply except as follows:

1 Scope and object
This clause of the General Standard applies except as follows:
1.1 Scope
Addition:
This Particular Standard applies to X-RAY EQUIPMENT for COMPUTED TOMOGRAPHY (CT
SCANNERS).
It includes safety requirements for the X-RAY GENERATOR, and those where HIGH VOLTAGE
GENERATORS are integrated with an X-RAY TUBE ASSEMBLY.
1.2 Object
Replacement:
The object of this standard is to establish particular requirements to ensure safety, and to
SCANNERS
specify methods for demonstrating compliance with those requirements, for CT .
NOTE 1 Requirements for reproducibility, linearity, constancy and accuracy are given because of their relationship
to the quality and quantity of the IONIZING RADIATION produced and are confined to those considered necessary for
safety.
NOTE 2 Both the levels for compliance and the tests prescribed to determine compliance reflect the fact that the
safety of HIGH-VOLTAGE GENERATORS is not sensitive to small differences in levels of performance. The combinations
of LOADING FACTORS specified for the tests are therefore limited in number but chosen from experience as being
LOADING FACTORS
appropriate in most cases. It is considered important to standardize the choice of combinations of
so that comparison can be made between tests performed in different places on different occasions. However,
combinations other than those specified could be of equal technical validity.
NOTE 3 The safety philosophy on which this standard is based is described in the introduction to the General
Standard and in IEC 60513.
RADIOLOGICAL PROTECTION
NOTE 4 Concerning it has been assumed in the preparation of this standard that
MANUFACTURERS USERS
and do accept the general principles of the ICRP as stated in ICRP 60, 1990,
1)
paragraph 112, namely:
"(a) No practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the
exposed individuals or to society to offset the radiation detriment it causes. (The justification of a practice.)
(b) In relation to any particular source within a practice, the magnitude of individual doses, the number of people
exposed, and the likelihood of incurring exposures where these are not certain to be received should all be kept as
low as reasonably achievable, economic and social factors being taken into account. This procedure should be
constrained by restrictions on the doses to individuals (dose constraints), or the risks to individuals in the case of
potential exposures (risk constraints), so as to limit the inequity likely to result from the inherent economic and
social judgements. (The optimisation of protection.)
___________
1)
ICRP Publication 60: Recommendations of the International Commission on Radiological Protection (Annals of
the ICRP Vol. 21 No 1-3, 1990). Published by Pergamon Press

60601-2-44 © IEC:2001(E) – 7 –

(c) The exposure of individuals resulting from the combination of all the relevant practices should be subject to

dose limits, or to some control of risk in the case of potential exposures. These are aimed at ensuring that no

individual is exposed to radiation risks that are judged to be unacceptable from these practices in any normal
circumstances. Not all sources are susceptible of control by action at the source and it is necessary to specify the

sources to be included as relevant before selecting a dose limit. (Individual dose and risk limits.)"

NOTE 5 Most of the requirements on X-RAY EQUIPMENT and its sub-assemblies for protection against IONIZING

RADIATION
are given in the Collateral Standard IEC 60601-1-3.

RADIOLOGICAL PROTECTION
This standard does, however, deal with some aspects of , mainly those that depend upon

HIGH VOLTAGE GENERATOR
the supply, control and indication of electrical energy from the - .

NOTE 6 It is recognized that many of the judgements necessary to follow the ICRP general principles have to be

made by the USER and not by the MANUFACTURER of the EQUIPMENT.

1.3 Particular Standards
Addition:
This Particular Standard, hereinafter referred to as "this standard", amends and supplements
a set of IEC publications, hereinafter referred to as "General Standard", consisting of
IEC 60601-1:1988, Medical electrical equipment – Part 1: General requirements for safety, its
amendments No. 1 (1991) and No. 2 (1995), and all Collateral Standards. The numbering of
sections, clauses and subclauses of this standard corresponds to that of the General Standard.
The changes to the text of the General Standard are specified by the use of the following
words:
"Replacement" means that the clause or subclause of the General Standard is replaced
completely by the text of this standard.
"Addition" means that the text of this standard is additional to the requirements of the General
Standard.
"Amendment" means that the clause or subclause of the General Standard is amended as
indicated by the text of this standard.
Subclauses or figures which are additional to those of the General Standard are numbered
starting from 101, additional annexes are lettered AA, BB, etc., and additional items aa), bb),
etc.
Where there is no corresponding section, clause or subclause in this standard, the section,
clause or subclause of the General Standard applies without modification.
Where it is intended that any part of the General Standard, although possibly relevant, is not to
be applied, a statement to that effect is given in this standard.

A requirement of this standard replacing or modifying requirements of the General Standard
takes precedence over the original requirements concerned.
1.3.101 Related International Standards
IEC 60601-1-2:1993, Medical electrical equipment – Part 1: General requirements for safety –
2. Collateral Standard: Electromagnetic compatibility – Requirements and tests
IEC 60601-1-3:1994, Medical electrical equipment – Part 1: General requirements for safety –
3. Collateral Standard: General requirements for radiation protection in diagnostic X-ray
equipment
– 8 – 60601-2-44 IEC:2001(E)

IEC 60601-2-28:1993, Medical electrical equipment – Part 2: Particular requirements for the

safety of X-ray source assemblies and X-ray tube assemblies for medical diagnosis

IEC 60664-1:1992, Insulation coordination for equipment within low-voltage systems – Part 1:

Principles, requirements and tests

IEC 60788:1984, Medical radiology – Terminology

ISO 2092:1981, Light metals and their alloys – Code of designation based on chemical symbols

2 Terminology and definitions
This clause of the General Standard applies except as follows:
Addition before 2.1:
In this standard, terms printed in SMALL CAPITALS are used in accordance with their definitions
in the General Standard or in IEC 60788.
NOTE Attention is drawn to the fact, that in cases where the concept addressed is not strongly confined to the
definition given in one of the publications listed above a corresponding term is printed in lower case letters.
An index of defined terms used in this standard is given in annex AA.
Associated conditions qualifying the usage of certain terms are given in the additional
definitions below.
In this standard unless otherwise indicated:
– values of X-RAY TUBE VOLTAGE refer to peak values, transients being disregarded;
– values of X-RAY TUBE CURRENT refer to average values.
Additional definitions:
2.101
CT SCANNER
X-RAY EQUIPMENT for COMPUTED TOMOGRAPHY (CT). A computed tomography X-ray system is a
diagnostic X-ray system intended to generate cross-sectional images of the body by computer
reconstruction of X-ray transmission data from the same axial plane at different angles. This

generic type of device may include signal analysis and display equipment, patient and
equipment supports, support parts and ACCESSORIES.
NOTE Secondary imaging processing is not included in the scope of this standard.
2.102
CONDITIONS OF OPERATION
CT
all selectable parameters governing the operation of a CT SCANNER, for example NOMINAL
TOMOGRAPHIC SECTION THICKNESS, PITCH FACTOR, FILTRATION, peak X-RAY TUBE VOLTAGE and
either X-RAY TUBE CURRENT and LOADING TIME or CURRENT TIME PRODUCT

60601-2-44 © IEC:2001(E) – 9 –

y
T x
z
IEC  522/01
1TOMOGRAPHIC PLANE
2 PHANTOM
Figure 101 – Coordinate system
2.103
DOSE PROFILE
the representation of the dose as a function of position along a line
2.104
SENSITIVITY PROFILE
COMPUTED TOMOGRAPHY
the relative response of a system for as a function of position along a
line perpendicular to the TOMOGRAPHIC PLANE
2.105
TOMOGRAPHIC PLANE
the geometric plane perpendicular to the axis of rotation (see figure 101)
2.106
CTDI
COMPUTED TOMOGRAPHY DOSE INDEX 100 ( )
the integral of the DOSE PROFILE along a line perpendicular to the TOMOGRAPHIC PLANE from
–50 mm to +50 mm, divided by the product of the number of TOMOGRAPHIC SECTIONS
N
produced in a single scan and the NOMINAL TOMOGRAPHIC SECTION THICKNESS
T
+50 mm
D (z)
=  dz
CTDI100
∫
N x T
−50 mm
where
is the DOSE PROFILE along a line perpendicular to the TOMOGRAPHIC PLANE, where dose
D(z) z
AIR KERMA
is measured in ;
is the number of TOMOGRAPHIC SECTIONS produced in a single rotation of the RADIATION
N
SOURCE;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS.

– 10 – 60601-2-44 IEC:2001(E)

NOTE 1 The term CTDI100 has been introduced as a more representative value for dose than the traditional CTDI

integrated from –7T to +7T as defined by the FDA in 21 CFR Ch. I § 1020.33 .

NOTE 2 The dose is measured as AIR KERMA. This is required in order to avoid present confusion, as some

MANUFACTURERS of CT SCANNERS express dose values calculated as ABSORBED DOSE to air and others as ABSORBED

DOSE to polymethyl-methacrylate (PMMA).

NOTE 3 This definition assumes that the DOSE PROFILE is centred on z = 0 and that for CT SCANNERS, which

acquire two or more TOMOGRAPHIC SECTIONS in one rotation, the increment between adjacent scans is N T. For
×
helical scans it assumes that the horizontal table travel per rotation is equal to N times the NOMINAL TOMOGRAPHIC

SECTION THICKNESS.
2.107
CT PITCH FACTOR
the ratio of the PATIENT SUPPORT travel in horizontal direction per rotation of the X-RAY TUBE
divided by the NOMINAL TOMOGRAPHIC SECTION THICKNESS T
Δd
CT pitch factor = where
T
is the PATIENT SUPPORT travel in horizontal direction;
Δd
is the NOMINAL TOMOGRAPHIC SECTION THICKNESS
T
2.108
TOMOGRAPHIC SECTION
the volume of an object in which the properties of ATTENUATION of X-RADIATION are imaged
2.109
TOMOGRAPHIC SECTION THICKNESS
the FULL WIDTH AT HALF MAXIMUM of the SENSITIVITY PROFILE taken at the centre of the cross-
TRANSMISSION RADIATION
sectional volume over which data of X- are collected
2.110
NOMINAL TOMOGRAPHIC SECTION THICKNESS
In CT SCANNERS the TOMOGRAPHIC SECTION THICKNESS which is selected and indicated on the
CONTROL PANEL
3 General requirements
This clause of the General Standard applies except as follows:
3.1 Addition:
CT SCANNERS shall be designed so as not to deliver a voltage higher than the NOMINAL X-RAY
TUBE VOLTAGE RAY TUBE ASSEMBLY
for the X- .
5 Classification
This clause of the General Standard applies except as follows:

5.1 Replacement:
HIGH VOLTAGE GENERATORS in CT SCANNERS shall be CLASS I EQUIPMENT or INTERNALLY
POWERED EQUIPMENT.
5.6 Replacement:
___________
See bibliography.
60601-2-44 © IEC:2001(E) – 11 –

Unless otherwise specified, CT SCANNERS or sub-assemblies thereof shall be classified as

suitable for continuous connection to the SUPPLY MAINS in the STAND-BY STATE and for specified

LOADINGS; see also 6.1 m) and 6.8.101.

6 Identification, marking and documents

This clause of the General Standard applies except as follows:

EQUIPMENT EQUIPMENT
6.1 Marking on the outside of or parts

g) Connection to the supply
Addition:
SCANNERS
For CT that are specified to be permanently installed, the information required in
6.1 g) of the General Standard may be stated only in the ACCOMPANYING DOCUMENTS.
m) Mode of operation
Replacement:
The mode of operation – where appropriate, together with maximum permissible ratings – shall
be stated in the ACCOMPANYING DOCUMENTS; see 6.8.101.
p) Output
Replacement:
This subclause of the General Standard does not apply.
t) Cooling conditions
Addition:
SCANNER
The cooling requirements for the safe operation of a CT , or a sub-assembly thereof,
shall be indicated in the ACCOMPANYING DOCUMENTS, including as appropriate the maximum
heat dissipation.
6.7 Indicator lights and push-buttons
a) Colours of indicator lights
Addition after the first paragraph:
For CT SCANNERS, the colours to be used for indicator lights shall be as follows:
– the colour green shall be used at the CONTROL PANEL to indicate the state from which one
further action leads to the LOADING STATE; see 29.1.101.1 a);

– 12 – 60601-2-44 IEC:2001(E)

– the colour yellow shall be used at the CONTROL PANEL to indicate the LOADING STATE; see

29.1.101.1 b).
NOTE The colours of indicator lights need to be chosen according to the message to be given. Thus, the same

EQUIPMENT
operational state of an can have simultaneous indications in different colours depending upon the place

of indication, for example green at the CONTROL PANEL and red at the entrance to the EXAMINATION ROOM.

6.8 ACCOMPANYING DOCUMENTS
6.8.2 INSTRUCTIONS FOR USE
a) General information
Addition:
INSTRUCTIONS FOR USE LOADING FACTORS
Electric output data shall be stated in the in terms of
as described in 6.8.2 a) 1) to 6.8.2 a) 4).
For CT SCANNERS in which part of the HIGH-VOLTAGE GENERATOR is integrated with the X-RAY
TUBE ASSEMBLY (for example X-RAY TUBE HEADS) the stated values shall refer to the complete
device.
The following combinations and data shall be stated:
1) The corresponding NOMINAL X-RAY TUBE VOLTAGE together with the highest X-RAY TUBE
CURRENT obtainable from the HIGH-VOLTAGE GENERATOR when operated at that X-RAY TUBE
VOLTAGE
.
RAY TUBE CURRENT RAY TUBE
2) The corresponding highest X- together with the highest X-
VOLTAGE HIGH VOLTAGE GENERATOR RAY TUBE
, obtainable from the - when operating at that X-
CURRENT.
3) The corresponding combination of X-RAY TUBE VOLTAGE and X-RAY TUBE CURRENT which
results in the highest electric output power.
4) The NOMINAL ELECTRIC POWER given as the highest constant electric output power in
kilowatts which the HIGH-VOLTAGE GENERATOR can deliver, for a LOADING TIME of 4 s at an
X-RAY TUBE VOLTAGE of 120 kV, or if these values are not selectable, with an X-RAY TUBE
VOLTAGE LOADING TIME
nearest to 120 kV and the value of nearest to but not less than 4 s.
The NOMINAL ELECTRIC POWER shall be given together with the combination of X-RAY TUBE
VOLTAGE and X-RAY TUBE CURRENT and the LOADING TIME which are used in the CT SCANNER.
6.8.3 Technical description
a) General
Addition:
The technical description shall contain information about the combination or, if necessary, the
combinations of sub-assemblies and ACCESSORIES of a CT SCANNER.
NOTE Attention is drawn to the usefulness in the technical description of
– data and essential characteristics to determine the ratings of an earth leakage circuit breaker, or
– indication of the types of earth leakage circuit breakers which can be used with the HIGH-VOLTAGE GENERATOR.

60601-2-44 © IEC:2001(E) – 13 –

Addition:
6.8.101 Reference to ACCOMPANYING DOCUMENTS

Clauses and subclauses of this standard in which additional requirements concerning the

content of ACCOMPANYING DOCUMENTS are given:

Mode of operation and specified LOADINGS 5.6 and 6.1 m)
..........................................................

Connection to the supply 6.1 g)
..................................................................................................

Frequency of SUPPLY MAINS 6.1 h)
..............................................................................................

Power input 6.1 j)
......................................................................................................................
PPARENT RESISTANCE OF SUPPLY MAINS
A 10.2.2
............................................................................
Cooling conditions 6.1 t)
............................................................................................................
Electric output data of the HIGH-VOLTAGE GENERATOR
and LOADING FACTORS 6.8.2 a) and 50.101
............................................................................
Suitable combinations for compliance test 6.8.3 a) and 50.1
.......................................................
Earth leakage circuit breaker 6.8.3 a)
........................................................................................
Compliance with this standard 6.8.102
.......................................................................................
Central connection point PROTECTIVE EARTH CONDUCTOR 19.3
......................................................
6.8.102 Statement of compliance
If for a CT SCANNER, or a sub-assembly thereof, compliance with this standard is to be stated,
the statement shall be stated in the ACCOMPANYING DOCUMENTS:
++)
SCANNER
CT . IEC 60601-2-44: 2001
++)
MODEL OR TYPE REFERENCE
ACCOMPANYING DOCUMENTS
Compliance is checked by inspection of the .
SECTION 2: ENVIRONMENTAL CONDITIONS
The clauses and subclauses of this section of the General Standard apply except as follows:

10 Environmental conditions
This clause of the General Standard applies except as follows:
10.2.2 Power supply
Item a)
Addition:
The internal impedance of a SUPPLY MAINS is to be considered sufficiently low for the operation
of a CT SCANNER if the value of the APPARENT RESISTANCE OF SUPPLY MAINS does not exceed
the value specified in the ACCOMPANYING DOCUMENTS.

– 14 – 60601-2-44 IEC:2001(E)

NOTE If a NOMINAL voltage is claimed for a mains power supply system, it is assumed that there is no voltage of a

higher value between any of the conductors of the system or between any of these conductors and earth.

An alternating voltage is considered in practice to be sinusoidal if any instantaneous value of the waveform

concerned differs from the instantaneous value of the ideal waveform at the same moment by no more than ±2 % of

the peak value of the ideal waveform.

SUPPLY MAINS
A three-phase is considered to have a practical symmetry if it delivers symmetrical voltages and

produces, when loaded symmetrically, symmetrical currents.

The requirements of this standard are based upon the assumption that three-phase systems have a symmetrical
MAINS VOLTAGE
configuration of the with respect to earth. Single-phase systems may be derived from such
three-phase systems. Where the supply system is not earthed at the source it is assumed that adequate measures

have been provided to detect, limit and remedy any disturbance of symmetry within a reasonably short time.

SCANNER NOMINAL ELECTRIC
A CT is considered to comply with the requirements of this standard only if its specified

POWER APPARENT RESISTANCE OF SUPPLY MAINS
can be demonstrated at an having a value not less than the
APPARENT RESISTANCE OF SUPPLY MAINS specified by the MANUFACTURER in the ACCOMPANYING DOCUMENTS.
Compliance is checked by inspection.
SECTION 3: PROTECTION AGAINST ELECTRIC SHOCK HAZARDS
The clauses and subclauses of this section of the General Standard apply except as follows:
15 Limitation of voltage and/or energy
This clause of the General Standard applies except as follows:
Addition:
aa) Detachable high-voltage cable connections to the X-RAY TUBE ASSEMBLY shall be
designed so that the use of TOOLS is required to disconnect them or to remove their
PROTECTIVE COVERS.
Compliance is checked by inspection.
bb) Provision shall be made to prevent the appearance of an unacceptably high-voltage in
MAINS PART
the or in any other low-voltage circuit.
NOTE This may be achieved for example:
– by provision of a winding layer or a conductive screen connected to the PROTECTIVE EARTH TERMINAL between
high-voltage and low-voltage circuits;
– by provision of a voltage-limiting device across terminals to which external devices are connected and between

which an excessive voltage might arise if the external path becomes discontinuous.
Compliance is checked by inspection of design data and construction.
NCLOSURES PROTECTIVE COVERS
16 E and
This clause of the General Standard applies except as follows:
Addition:
NOTE Requirements concerning the resistance and earthing of a flexible conductive screen of high-voltage cables
connected to X-RAY TUBE ASSEMBLIES are given in IEC 60601-2-28.

60601-2-44 © IEC:2001(E) – 15 –

LEAKAGE CURRENTS PATIENT AUXILIARY CURRENTS
19 Continuous and
This clause of the General Standard applies except as follows:

19.3 Allowable values
Addition:
FOR CT SCANNERS the column on TYPE B and the rows on EARTH LEAKAGE CURRENT in NORMAL

CONDITION and SINGLE FAULT CONDITION and on ENCLOSURE LEAKAGE CURRENT in NORMAL

CONDITION of table IV, including the notes, of the General Standard apply.
The allowable values of EARTH LEAKAGE CURRENT are permitted for each sub-assembly of CT
SCANNERS SUPPLY MAINS
that is supplied by its own exclusive connection to the or to a central
connection point, if the latter is fixed and permanently installed.
A fixed and permanently installed central PROTECTIVE EARTH TERMINAL may be provided inside
the outer ENCLOSURE or cover of the CT SCANNER. If other sub-assemblies or ASSOCIATED
EQUIPMENT are connected to the PROTECTIVE EARTH TERMINAL, the EARTH LEAKAGE CURRENT
between such a central connection point and the external protective system may exceed the
allowable values for any one of the single devices connected.
NOTE The limitation of the EARTH LEAKAGE CURRENTS within the environment of a CT SCANNER is intended to
ensure that ACCESSIBLE PARTS do not become live and to prevent interference in other electrical equipment.
The provision of a central PROTECTIVE EARTH TERMINAL is acceptable, as for fixed and PERMANENTLY INSTALLED
EQUIPMENT the interruption of the PROTECTIVE EARTH CONDUCTOR is not considered to be a SINGLE FAULT CONDITION.
However, in such cases, adequate information on the combination of ASSOCIATED EQUIPMENT needs to be provided
in accordance with 6.8.3 a).
Compliance is checked by inspection.
20 Dielectric strength
This clause of the General Standard applies except as follows:
20.3 Values of test voltages
Addition:
The dielectric strength of the electrical insulation of high-voltage circuits shall be sufficient to
withstand the test voltages for the durations given in 20.4 a).
The test shall be made without an X-RAY TUBE connected and with a test voltage of 1,2 times
the NOMINAL X-RAY TUBE VOLTAGE of the HIGH-VOLTAGE GENERATOR.
HIGH VOLTAGE GENERATOR RAY TUBE
If the - can only be tested with the X- 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.
– 16 – 60601-2-44 IEC:2001(E)

20.4 Tests
Item a)
Addition:
The high-voltage circuits of HIGH-VOLTAGE GENERATORS or sub-assemblies thereof are tested by

applying a test voltage of 50 % of its final value according to 20.3 and raising it over a period of

10 s or less to the final value, which then is maintained for 3 min.

If during the dielectric strength test there is a risk of overheating a transformer or associated
circuitry under test, it is permitted to carry out the test at a higher supply frequency or to supply
the test voltage to the secondary side by another generator.
Item
d)
Replacement:
During the dielectric strength test, the test voltage in the high-voltage circuit should be kept to
100 % to 105 % of the value required.
Item f)
Addition:
During the dielectric strength test of HIGH-VOLTAGE GENERATORS slight corona discharges in the
high-voltage circuit are to be disregarded if they cease when the test voltage is lowered to
1,1 times the voltage to which the test condition is referred.
Item l)
Addition:
The test voltage for the dielectric strength testing of stator and stator circuits used for the
operation of the rotating ANODE of the X-RAY TUBE is to be referred to the voltage existing after
reduction of the stator supply voltage to its steady state operating value.
Additional item aa):
1) HIGH-VOLTAGE GENERATORS or sub-assemblies thereof that are integrated with an X-RAY
TUBE ASSEMBLY RAY TUBE
are to be tested with an appropriately loaded X- .
RAY TUBE
2) If the dielectric strength test is performed with an X- connected and the
high-voltage circuit is not accessible for the measurement of the test voltage applied,
appropriate measures are to be taken to ensure that the values lie within the limits required
in 20.4 d).
60601-2-44 © IEC:2001(E) – 17 –

SECTION 4: PROTECTION AGAINST MECHANICAL HAZARDS

The clauses and subclauses of this section of the General Standard apply except as follows:

22 Moving parts
Subclause 22.4 of IEC 60601-2-32 applies except as follows:

Addition:
22.4.101 Gantry and PATIENT SUPPORT
a) General
SUPPLY MAINS
1) Interruption or failure of powered movements or of the shall cause any
parts in motion to be stopped within the limits given in items b) and c). The maximum
value of distance and angle for each stopping condition shall be given in the
ACCOMPANYING DOCUMENTS.
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS and by interruption of
the SUPPLY MAINS to powered movements and measurement of stopping distances. These tests
shall be performed with a PATIENT-equivalent mass of 135 kg distributed evenly over the
PATIENT SUPPORT
.
2) When a part is provided with one or several devices designed to reduce, in NORMAL USE,
PATIENT
the risk of collision with the , the operation and limitations of each device shall
be described in the INSTRUCTIONS FOR USE.
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS.
3) Where there is a possibility that a failure of a powered movement during NORMAL USE of
the EQUIPMENT might result in the PATIENT being trapped, controls and switches shall be
provided to permit the release of the PATIENT. These means shall be described in the
INSTRUCTIONS FOR USE and on a label on the EQUIPMENT when a deliberate action is
required.
ACCOMPANYING DOCUMENTS
Compliance is checked by inspection of the .
b) Tilting of the gantry
When the emergency stop control is actuated, the gantry tilt shall stop within an angle of 0,5 .
°
Compliance is checked by inspection.

c) Linear movements of the PATIENT SUPPORT
When the emergency stop control is actuated, the PATIENT SUPPORT shall stop within a distance
of 10 mm.
Compliance is checked by inspection.
22.4.102 Operation of EQUIPMENT movements from inside the RADIATION room
Any motorized movements of equipment parts which may cause physical injury to the PATIENT
OPERATOR
shall be controlled by continuous deliberate action by the .

– 18 – 60601-2-44 IEC:2001(E)

The control shall be located close to the PATIENT SUPPORT so that the OPERATOR can
continuously observe the PATIENT and thus avoid possible injury to the latter and be positioned
in such a way that it cannot easily be touched by the PATIENT.

22.4.103 Operation of EQUIPMENT movements from outside the RADIATION room

Any motorized movements of equipment parts which may cause physical injury to the PATIENT

shall be controlled by continuous deliberate action by the OPERATOR. Those movements which

are part of a pre-programmed scanning protocol are exempt from this requirement.

Subclause 22.7 of IEC 60601-1 applies except as follows:
Addition:
22.7.101 Emergency stop of motorized movements
Readily identifiable and accessible controls and switches shall be provided in hard-wired
circuits near to, or on, the PATIENT SUPPORT and/or gantry, for emergency stopping of all
motorized movements by interruption of the SUPPLY MAINS to the movement system. When
operated, any movement shall stop within the limits given in 22.4.101. These controls and
switches shall be positioned in such a way that they cannot be operated accidentally.
CONTROL PANEL
Similar controls shall also be provided near to, or on, any remote from which
movements can be actuated.
The time to effect the disconnection of the SUPPLY MAINS after initiation by the controls and
switches shall not exceed 0,5 s.
SUPPLY
NOTE The controls provided for emergency stopping of all motorized movements by interruption of the
MAINS to the movement system should also terminate LOADING as described in 29.1.101. Both controls may be the
same emergency stop button.
Compliance is checked by inspection and measurement of stopping distances and
disconnection time.
27 Pneumatic and hydraulic power
This clause of the General Standard applies except as follows:
Addition:
27.101 Variations of PRESSURE in PRESSURE-powered movements of CT SCANNERS
If a hazardous situation can arise from a change in the PRESSURE of a system used to provide
power for movements, all movements shall stop within the limits specified in 22.4.101.
Compliance is checked by simulation of a fault condition, the operation of protective devices
and measurement of stopping distances.

60601-2-44 © IEC:2001(E) – 19 –

SECTION 5: PROTECTION AGAINST HAZARDS FROM UNWANTED OR

EXCESSIVE RADIATION
The clauses and subclauses of this section of the General Standard apply except as follows:

29 X-RADIATION
This clause of the General Standard applies except as follows:

Additional subclauses:
RADIATION
29.1.101 Emergency termination of X-
Readily identifiable and accessible means shall be provided in hard-wired circuits near to, or
PATIENT SUPPORT LOADING
on, the and/or the gantry for emergency interruption to terminate .
NOTE The means provided for emergency interruption of all SUPPLY MAINS to terminate LOADING should also stop
all movements as described in 22.4.101 b), 22.4.101 c) and 22.7.101. Both means may be the same emergency
stop button.
Compliance is checked by the appropriate functional tests.
29.1.101.1 Indication of operational states
a) READY STATE
Visible indication shall be provided on the CONTROL PANEL indicating the state when one further
actuation of a control from that CONTROL PANEL will initiate the LOADING of the X-RAY TUBE.
If this state is indicated by means of a single-function indicator light, the colour green shall be
used; see 6.7 a).
Means shall be provided for a connection to enable this state to be indicated remotely from the
CONTROL PANEL. This requirement does not apply for MOBILE EQUIPMENT.
b) LOADING STATE
The LOADING STATE shall be indicated by a yellow indicator light on the CONTROL PANEL of the
CT system; see 6.7 a).
Compliance is checked by inspection and by the appropriate functional tests.
RADIATION
29.1.101.2 Limitation of output
a) Means shall be provided to limit the electric energy to be delivered by the use of fixed or
LOADING FACTORS
pre-selected combinations of suitable and modes of operation.
During IRRADIATION, the OPERATOR shall be able to
...

IEC 60601-2-44
Edition 2.1 2002-11
INTERNATIONAL
STANDARD
Medical electrical equipment –
Part 2-44: Particular requirements for the safety of X-ray equipment for
computed tomography
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

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IEC 60601-2-44
Edition 2.1 2002-11
INTERNATIONAL
STANDARD
Medical electrical equipment –
Part 2-44: Particular requirements for the safety of X-ray equipment for
computed tomography
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
CM
ICS 11.040.50 ISBN 2-8318-6691-X

– 2 – 60601-2-44 © IEC:2001+A1:2002(E)

CONTENTS
FOREWORD . 4

SECTION 1: GENERAL
1 Scope and object . 6

1.1 Scope . 6

1.2 Object . 6

1.3 Particular Standards. 7
2 Terminology and definitions. 8
3 General requirements.11
5 Classification.11
6 Identification, marking and documents.11
6.1 Marking on the outside of EQUIPMENT or EQUIPMENT parts .11
6.7 Indicator lights and push-buttons.12
6.8 ACCOMPANYING DOCUMENTS.12
SECTION 2: ENVIRONMENTAL CONDITIONS
10 Environmental conditions .14
SECTION 3: PROTECTION AGAINST ELECTRIC SHOCK HAZARDS
15 Limitation of voltage and/or energy.15
16 ENCLOSURES and PROTECTIVE COVERS .15
19 Continuous LEAKAGE CURRENTS and PATIENT AUXILIARY CURRENTS.15
19.3 Allowable values .15
20 Dielectric strength .16
20.3 Values of test voltages .16
20.4 Tests.16
SECTION 4: PROTECTION AGAINST MECHANICAL HAZARDS
22 Moving parts .18
27 Pneumatic and hydraulic power .19

SECTION 5: PROTECTION AGAINST HAZARDS FROM UNWANTED OR
EXCESSIVE RADIATION
29 X-RADIATION.20
36 Electromagnetic compatibility .28

60601-2-44 © IEC:2001+A1:2002(E) – 3 –

SECTION 6: PROTECTION AGAINST HAZARDS OF IGNITION OF

FLAMMABLE ANAESTHETIC MIXTURES

SECTION 7: PROTECTION AGAINST EXCESSIVE TEMPERATURES AND

OTHER SAFETY HAZARDS
42 Excessive temperatures .29

SECTION 8: ACCURACY OF OPERATING DATA AND PROTECTION

AGAINST HAZARDOUS OUTPUT
50 Accuracy of operating data.29

50.101 Accuracy of radiation output .29
50.102 Accuracy of recorded examination data .29
51 Protection against hazardous output.30
SECTION 9: ABNORMAL OPERATION AND FAULT CONDITIONS;
ENVIRONMENTAL TESTS
SECTION 10: CONSTRUCTIONAL REQUIREMENTS
56 Components and general assembly.31
56.7 Batteries .31
57 MAINS PARTS, components and layout .31
57.10 CREEPAGE DISTANCES and AIR CLEARANCES .31
Tables
101 HALF-VALUE LAYERS in CT SCANNERS .26
Figures
101 Coordinate system . 9
Annex AA (normative) Terminology – Index of defined terms .32
Annex BB (informative) Choosing LOADING FACTORS for tests.35
Bibliography.36

– 4 – 60601-2-44 © IEC:2001+A1:2002(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
MEDICAL ELECTRICAL EQUIPMENT –

Part 2-44: Particular requirements for the safety of

X-ray equipment for computed tomography

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60601-2-44 has been prepared by subcommittee 62B: Diagnostic
imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice.
This consolidated version of IEC 60601-2-44 consists of the second edition (2001)
[documents 62B/426/FDIS and 62B/437/RVD] and its amendment 1 (2002) [documents
62B/472/FDIS and 62B/478/RVD].
The technical content is therefore identical to the base edition and its amendment and has
been prepared for user convenience.
It bears the edition number 2.1.
A vertical line in the margin shows where the base publication has been modified by
amendment 1.
Annex AA forms an integral part of this standard.
Annex BB is for information only.

60601-2-44 © IEC:2001+A1:2002(E) – 5 –

In this standard, the following print types are used:

– requirements, compliance with which can be tested and definitions: roman type:

– explanations, advice, notes, general statements and exceptions: smaller type;

– test specifications and headings of subclauses: italic type;

– TERMS DEFINED IN CLAUSE 2 OF THE GENERAL STANDARD OR IN IEC 60788: SMALL CAPITALS.

The committee has decided that the contents of the base publication and its amendment 1 will

remain unchanged until 2004. At this date, the publication will be

• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 6 – 60601-2-44 © IEC:2001+A1:2002(E)

MEDICAL ELECTRICAL EQUIPMENT –

Part 2-44: Particular requirements for the safety of

X-ray equipment for computed tomography

SECTION 1: GENERAL
The clauses and subclauses of this section of the General Standard apply except as follows:

1 Scope and object
This clause of the General Standard applies except as follows:
1.1 Scope
Addition:
This Particular Standard applies to X-RAY EQUIPMENT for COMPUTED TOMOGRAPHY (CT
SCANNERS).
It includes safety requirements for the X-RAY GENERATOR, and those where HIGH VOLTAGE
GENERATORS are integrated with an X-RAY TUBE ASSEMBLY.
1.2 Object
Replacement:
The object of this standard is to establish particular requirements to ensure safety, and to
specify methods for demonstrating compliance with those requirements, for CT SCANNERS.
NOTE 1 Requirements for reproducibility, linearity, constancy and accuracy are given because of their
relationship to the quality and quantity of the IONIZING RADIATION produced and are confined to those considered
necessary for safety.
NOTE 2 Both the levels for compliance and the tests prescribed to determine compliance reflect the fact that the
safety of HIGH-VOLTAGE GENERATORS is not sensitive to small differences in levels of performance. The
combinations of LOADING FACTORS specified for the tests are therefore limited in number but chosen from
experience as being appropriate in most cases. It is considered important to standardize the choice of
combinations of LOADING FACTORS so that comparison can be made between tests performed in different places on
different occasions. However, combinations other than those specified could be of equal technical validity.
NOTE 3 The safety philosophy on which this standard is based is described in the introduction to the General
Standard and in IEC 60513.
NOTE 4 Concerning RADIOLOGICAL PROTECTION it has been assumed in the preparation of this standard that
MANUFACTURERS and USERS do accept the general principles of the ICRP as stated in ICRP 60, 1990,
1)
paragraph 112, namely:
"(a) No practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the
exposed individuals or to society to offset the radiation detriment it causes. (The justification of a practice.)
(b) In relation to any particular source within a practice, the magnitude of individual doses, the number of people
exposed, and the likelihood of incurring exposures where these are not certain to be received should all be kept as
low as reasonably achievable, economic and social factors being taken into account. This procedure should be
constrained by restrictions on the doses to individuals (dose constraints), or the risks to individuals in the case of
potential exposures (risk constraints), so as to limit the inequity likely to result from the inherent economic and
social judgements. (The optimisation of protection.)
___________
1)
ICRP Publication 60: Recommendations of the International Commission on Radiological Protection (Annals of
the ICRP Vol. 21 No 1-3, 1990). Published by Pergamon Press.

60601-2-44 © IEC:2001+A1:2002(E) – 7 –

(c) The exposure of individuals resulting from the combination of all the relevant practices should be subject to

dose limits, or to some control of risk in the case of potential exposures. These are aimed at ensuring that no
individual is exposed to radiation risks that are judged to be unacceptable from these practices in any normal

circumstances. Not all sources are susceptible of control by action at the source and it is necessary to specify the

sources to be included as relevant before selecting a dose limit. (Individual dose and risk limits.)"

NOTE 5 Most of the requirements on X-RAY EQUIPMENT and its sub-assemblies for protection against IONIZING

RADIATION are given in the Collateral Standard IEC 60601-1-3.

This standard does, however, deal with some aspects of RADIOLOGICAL PROTECTION, mainly those that depend upon

the supply, control and indication of electrical energy from the HIGH-VOLTAGE GENERATOR.

NOTE 6 It is recognized that many of the judgements necessary to follow the ICRP general principles have to be
made by the USER and not by the MANUFACTURER of the EQUIPMENT.

1.3 Particular Standards
Addition:
This Particular Standard, hereinafter referred to as "this standard", amends and supplements
a set of IEC publications, hereinafter referred to as "General Standard", consisting of
IEC 60601-1:1988, Medical electrical equipment – Part 1: General requirements for safety, its
amendments No. 1 (1991) and No. 2 (1995), and all Collateral Standards. The numbering of
sections, clauses and subclauses of this standard corresponds to that of the General
Standard. The changes to the text of the General Standard are specified by the use of the
following words:
"Replacement" means that the clause or subclause of the General Standard is replaced
completely by the text of this standard.
"Addition" means that the text of this standard is additional to the requirements of the General
Standard.
"Amendment" means that the clause or subclause of the General Standard is amended as
indicated by the text of this standard.
Subclauses or figures which are additional to those of the General Standard are numbered
starting from 101, additional annexes are lettered AA, BB, etc., and additional items aa), bb),
etc.
Where there is no corresponding section, clause or subclause in this standard, the section,
clause or subclause of the General Standard applies without modification.
Where it is intended that any part of the General Standard, although possibly relevant, is not
to be applied, a statement to that effect is given in this standard.

A requirement of this standard replacing or modifying requirements of the General Standard
takes precedence over the original requirements concerned.
1.3.101 Related International Standards
IEC 60601-1-2:1993, Medical electrical equipment – Part 1: General requirements for safety –
2. Collateral Standard: Electromagnetic compatibility – Requirements and tests
IEC 60601-1-3:1994, Medical electrical equipment – Part 1: General requirements for safety –
3. Collateral Standard: General requirements for radiation protection in diagnostic X-ray
equipment
– 8 – 60601-2-44 © IEC:2001+A1:2002(E)

IEC 60601-2-28:1993, Medical electrical equipment – Part 2: Particular requirements for the
safety of X-ray source assemblies and X-ray tube assemblies for medical diagnosis

IEC 60664-1:1992, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests

IEC 60788:1984, Medical radiology – Terminology

ISO 2092:1981, Light metals and their alloys – Code of designation based on chemical
symbols
2 Terminology and definitions
This clause of the General Standard applies except as follows:
Addition before 2.1:
In this standard, terms printed in SMALL CAPITALS are used in accordance with their definitions
in the General Standard or in IEC 60788.
NOTE Attention is drawn to the fact, that in cases where the concept addressed is not strongly confined to the
definition given in one of the publications listed above a corresponding term is printed in lower case letters.
An index of defined terms used in this standard is given in annex AA.
Associated conditions qualifying the usage of certain terms are given in the additional
definitions below.
In this standard unless otherwise indicated:
– values of X-RAY TUBE VOLTAGE refer to peak values, transients being disregarded;
– values of X-RAY TUBE CURRENT refer to average values.
Additional definitions:
2.101
CT SCANNER
X-RAY EQUIPMENT for COMPUTED TOMOGRAPHY (CT)
diagnostic X-ray system intended to generate cross-sectional images of the body by computer

reconstruction of X-ray transmission data obtained at different angles. This generic type of
device may include signal analysis and display equipment, PATIENT SUPPORT, support parts
and ACCESSORIES
NOTE Secondary imaging processing is not included in the scope of this standard.
2.102
CT CONDITIONS OF OPERATION
all selectable parameters governing the operation of a CT SCANNER, for example NOMINAL
TOMOGRAPHIC SECTION THICKNESS, PITCH FACTOR, FILTRATION, peak X-RAY TUBE VOLTAGE and
either X-RAY TUBE CURRENT and LOADING TIME or CURRENT TIME PRODUCT

60601-2-44 © IEC:2001+A1:2002(E) – 9 –

y
T
x
z
IEC  522/01
1TOMOGRAPHIC PLANE
2 PHANTOM
Figure 101 – Coordinate system
2.103
DOSE PROFILE
the representation of the dose as a function of position along a line
2.104
SENSITIVITY PROFILE
the relative response of a system for COMPUTED TOMOGRAPHY as a function of position along a
line perpendicular to the TOMOGRAPHIC PLANE
2.105
TOMOGRAPHIC PLANE
the geometric plane perpendicular to the axis of rotation (see figure 101)

– 10 – 60601-2-44 © IEC:2001+A1:2002(E)

2.106
COMPUTED TOMOGRAPHY DOSE INDEX 100 (CTDI )
integral of the DOSE PROFILE produced in a single axial scan along a line perpendicular to

the TOMOGRAPHIC PLANE from –50 mm to +50 mm, divided by the product of the number of

TOMOGRAPHIC SECTIONS N and the NOMINAL TOMOGRAPHIC SECTION THICKNESS T:

+50 mm
D (z)
=  dz
CTDI
∫
N × T
−50 mm
where
D(z) is the DOSE PROFILE along a line z perpendicular to the TOMOGRAPHIC PLANE, where
dose is reported as ABSORBED DOSE to air;
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 term CTDI has been introduced as a more representative value for dose than the traditional CTDI
1)
integrated from –7T to +7T as defined by the FDA in 21 CFR 1020.33 .
NOTE 2 The dose is reported as ABSORBED DOSE to air. This is required in order to avoid present confusion, as
some MANUFACTURERS of CT SCANNERS express dose values calculated as ABSORBED DOSE to air and others as
ABSORBED DOSE to polymethyl-methacrylate (PMMA).
Although CTDI refers to ABSORBED DOSE to air, for practical purposes the evaluation of ABSORBED DOSE to
air within a PMMA dosimetry PHANTOM is well approximated by measurement of the AIR KERMA with an
ionization chamber in the PHANTOM.
NOTE 3 This definition assumes that the DOSE PROFILE is centred on z = 0.
NOTE 4 A single axial scan is typically a 360° rotation of the X-RAY SOURCE.
2.107
CT PITCH FACTOR
in helical scanning the ratio of the PATIENT SUPPORT travel ∆d along the z direction per rotation
of the X-RAY SOURCE divided by the product of the NOMINAL TOMOGRAPHIC SECTION THICKNESS T
and the number of TOMOGRAPHIC SECTIONS N:
∆d
CT pitch factor =
N ×T
where
Δd is the PATIENT SUPPORT travel along the z direction per rotation of the X-RAY SOURCE;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;

N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-RAY
SOURCE.
2.108
TOMOGRAPHIC SECTION
volume over which TRANSMISSION data of X-RADIATION are collected in a single axial scan
NOTE In a CT SCANNER with multiple detector elements along the z-axis, it is the volume over which data are
collected by a single acquisition channel (selected grouping of elements) and not the total volume irradiated.
___________
1)
See bibliography.
60601-2-44 © IEC:2001+A1:2002(E) – 11 –

2.109
TOMOGRAPHIC SECTION THICKNESS
FULL WIDTH AT HALF MAXIMUM of the SENSITIVITY PROFILE taken at the iso-centre of a

TOMOGRAPHIC SECTION
2.110
NOMINAL TOMOGRAPHIC SECTION THICKNESS

in CT SCANNERS the TOMOGRAPHIC SECTION THICKNESS which is selected and indicated on the
CONTROL PANEL
NOTE In helical scanning the thickness of a reconstructed image depends on the helical reconstruction algorithm
and pitch, and hence this thickness may not equal the NOMINAL TOMOGRAPHIC SECTION THICKNESS. The thickness of

the reconstructed image may be indicated or selected prior to the helical scan.
3 General requirements
This clause of the General Standard applies except as follows:
3.1 Addition:
CT SCANNERS shall be designed so as not to deliver a voltage higher than the NOMINAL X-RAY
TUBE VOLTAGE for the X-RAY TUBE ASSEMBLY.
5 Classification
This clause of the General Standard applies except as follows:
5.1 Replacement:
HIGH VOLTAGE GENERATORS in CT SCANNERS shall be CLASS I EQUIPMENT or INTERNALLY
POWERED EQUIPMENT.
5.6 Replacement:
Unless otherwise specified, CT SCANNERS or sub-assemblies thereof shall be classified as
suitable for continuous connection to the SUPPLY MAINS in the STAND-BY STATE and for
specified LOADINGS; see also 6.1 m) and 6.8.101.
6 Identification, marking and documents

This clause of the General Standard applies except as follows:
6.1 Marking on the outside of EQUIPMENT or EQUIPMENT parts
g) Connection to the supply
Addition:
For CT SCANNERS that are specified to be permanently installed, the information required in
6.1 g) of the General Standard may be stated only in the ACCOMPANYING DOCUMENTS.

– 12 – 60601-2-44 © IEC:2001+A1:2002(E)

m) Mode of operation
Replacement:
The mode of operation – where appropriate, together with maximum permissible ratings –

shall be stated in the ACCOMPANYING DOCUMENTS; see 6.8.101.

p) Output
Replacement:
This subclause of the General Standard does not apply.
t) Cooling conditions
Addition:
The cooling requirements for the safe operation of a CT SCANNER, or a sub-assembly thereof,
shall be indicated in the ACCOMPANYING DOCUMENTS, including as appropriate the maximum
heat dissipation.
6.7 Indicator lights and push-buttons
a) Colours of indicator lights
Addition after the first paragraph:
For CT SCANNERS, the colours to be used for indicator lights shall be as follows:
– the colour green shall be used at the CONTROL PANEL to indicate the state from which one
further action leads to the LOADING STATE; see 29.1.101.1 a);
– the colour yellow shall be used at the CONTROL PANEL to indicate the LOADING STATE; see
29.1.101.1 b).
NOTE The colours of indicator lights need to be chosen according to the message to be given. Thus, the same
operational state of an EQUIPMENT can have simultaneous indications in different colours depending upon the place
of indication, for example green at the CONTROL PANEL and red at the entrance to the EXAMINATION ROOM.
6.8 ACCOMPANYING DOCUMENTS
6.8.2 INSTRUCTIONS FOR USE
a) General information
Addition:
Electric output data shall be stated in the INSTRUCTIONS FOR USE in terms of LOADING FACTORS
as described in 6.8.2 a) 1) to 6.8.2 a) 4).
For CT SCANNERS in which part of the HIGH-VOLTAGE GENERATOR is integrated with the X-RAY
TUBE ASSEMBLY (for example X-RAY TUBE HEADS) the stated values shall refer to the complete
device.
60601-2-44 © IEC:2001+A1:2002(E) – 13 –

The following combinations and data shall be stated:

1) The corresponding NOMINAL X-RAY TUBE VOLTAGE together with the highest X-RAY TUBE

CURRENT obtainable from the HIGH-VOLTAGE GENERATOR when operated at that X-RAY TUBE

VOLTAGE.
2) The corresponding highest X-RAY TUBE CURRENT together with the highest X-RAY TUBE

VOLTAGE, obtainable from the HIGH-VOLTAGE GENERATOR when operating at that X-RAY TUBE

CURRENT.
3) The corresponding combination of X-RAY TUBE VOLTAGE and X-RAY TUBE CURRENT which

results in the highest electric output power.

4) The NOMINAL ELECTRIC POWER given as the highest constant electric output power in
kilowatts which the HIGH-VOLTAGE GENERATOR can deliver, for a LOADING TIME of 4 s at an
X-RAY TUBE VOLTAGE of 120 kV, or if these values are not selectable, with an X-RAY TUBE
VOLTAGE nearest to 120 kV and the value of LOADING TIME nearest to but not less than 4 s.
The NOMINAL ELECTRIC POWER shall be given together with the combination of X-RAY TUBE
VOLTAGE and X-RAY TUBE CURRENT and the LOADING TIME which are used in the CT SCANNER.
6.8.3 Technical description
a) General
Addition:
The technical description shall contain information about the combination or, if necessary, the
combinations of sub-assemblies and ACCESSORIES of a CT SCANNER.
NOTE Attention is drawn to the usefulness in the technical description of
– data and essential characteristics to determine the ratings of an earth leakage circuit breaker, or
– indication of the types of earth leakage circuit breakers which can be used with the HIGH-VOLTAGE GENERATOR.
Addition:
6.8.101 Reference to ACCOMPANYING DOCUMENTS
Clauses and subclauses of this standard in which additional requirements concerning the
content of ACCOMPANYING DOCUMENTS are given:
Mode of operation and specified LOADINGS .5.6 and 6.1 m)
Connection to the supply. 6.1 g)

Protection against STRAY RADIATION .29.208
APPARENT RESISTANCE OF SUPPLY MAINS .10.2.2
Cooling conditions. 6.1 t)
Electric output data of the HIGH-VOLTAGE GENERATOR
and LOADING FACTORS . 6.8.2 a) and 50.101
Suitable combinations for compliance test. 6.8.3 a) and 50.1
Earth leakage circuit breaker. 6.8.3 a)
Compliance with this standard.6.8.102
Central connection point PROTECTIVE EARTH CONDUCTOR .19.3

– 14 – 60601-2-44 © IEC:2001+A1:2002(E)

6.8.102 Statement of compliance

If for a CT SCANNER, or a sub-assembly thereof, compliance with this standard is to be stated,
the statement shall be stated in the ACCOMPANYING DOCUMENTS:

++)
CT SCANNER. IEC 60601-2-44: 2001

++)
MODEL OR TYPE REFERENCE
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS.

SECTION 2: ENVIRONMENTAL CONDITIONS
The clauses and subclauses of this section of the General Standard apply except as follows:
10 Environmental conditions
This clause of the General Standard applies except as follows:
10.2.2 Power supply
Item a)
Addition:
The internal impedance of a SUPPLY MAINS is to be considered sufficiently low for the operation
of a CT SCANNER if the value of the APPARENT RESISTANCE OF SUPPLY MAINS does not exceed
the value specified in the ACCOMPANYING DOCUMENTS.
NOTE If a NOMINAL voltage is claimed for a mains power supply system, it is assumed that there is no voltage of a
higher value between any of the conductors of the system or between any of these conductors and earth.
An alternating voltage is considered in practice to be sinusoidal if any instantaneous value of the waveform
concerned differs from the instantaneous value of the ideal waveform at the same moment by no more than ±2 % of
the peak value of the ideal waveform.
A three-phase SUPPLY MAINS is considered to have a practical symmetry if it delivers symmetrical voltages and
produces, when loaded symmetrically, symmetrical currents.
The requirements of this standard are based upon the assumption that three-phase systems have a symmetrical
configuration of the MAINS VOLTAGE with respect to earth. Single-phase systems may be derived from such
three-phase systems. Where the supply system is not earthed at the source it is assumed that adequate measures

have been provided to detect, limit and remedy any disturbance of symmetry within a reasonably short time.
A CT SCANNER is considered to comply with the requirements of this standard only if its specified NOMINAL ELECTRIC
POWER can be demonstrated at an APPARENT RESISTANCE OF SUPPLY MAINS having a value not less than the
APPARENT RESISTANCE OF SUPPLY MAINS specified by the MANUFACTURER in the ACCOMPANYING DOCUMENTS.
Compliance is checked by inspection.

60601-2-44 © IEC:2001+A1:2002(E) – 15 –

SECTION 3: PROTECTION AGAINST ELECTRIC SHOCK HAZARDS

The clauses and subclauses of this section of the General Standard apply except as follows:

15 Limitation of voltage and/or energy

This clause of the General Standard applies except as follows:

Addition:
aa) Detachable high-voltage cable connections to the X-RAY TUBE ASSEMBLY shall be
designed so that the use of TOOLS is required to disconnect them or to remove their
PROTECTIVE COVERS.
Compliance is checked by inspection.
bb) Provision shall be made to prevent the appearance of an unacceptably high-voltage in
the MAINS PART or in any other low-voltage circuit.
NOTE This may be achieved for example:
– by provision of a winding layer or a conductive screen connected to the PROTECTIVE EARTH TERMINAL between
high-voltage and low-voltage circuits;
– by provision of a voltage-limiting device across terminals to which external devices are connected and between
which an excessive voltage might arise if the external path becomes discontinuous.
Compliance is checked by inspection of design data and construction.
16 ENCLOSURES and PROTECTIVE COVERS
This clause of the General Standard applies except as follows:
Addition:
NOTE Requirements concerning the resistance and earthing of a flexible conductive screen of high-voltage
cables connected to X-RAY TUBE ASSEMBLIES are given in IEC 60601-2-28.
19 Continuous LEAKAGE CURRENTS and PATIENT AUXILIARY CURRENTS
This clause of the General Standard applies except as follows:
19.3 Allowable values
Addition:
FOR CT SCANNERS the column on TYPE B and the rows on EARTH LEAKAGE CURRENT in NORMAL
CONDITION and SINGLE FAULT CONDITION and on ENCLOSURE LEAKAGE CURRENT in NORMAL
CONDITION of table IV, including the notes, of the General Standard apply.
The allowable values of EARTH LEAKAGE CURRENT are permitted for each sub-assembly of CT
SCANNERS that is supplied by its own exclusive connection to the SUPPLY MAINS or to a central
connection point, if the latter is fixed and permanently installed.

– 16 – 60601-2-44 © IEC:2001+A1:2002(E)

A fixed and permanently installed central PROTECTIVE EARTH TERMINAL may be provided inside
the outer ENCLOSURE or cover of the CT SCANNER. If other sub-assemblies or ASSOCIATED

EQUIPMENT are connected to the PROTECTIVE EARTH TERMINAL, the EARTH LEAKAGE CURRENT

between such a central connection point and the external protective system may exceed the

allowable values for any one of the single devices connected.

NOTE The limitation of the EARTH LEAKAGE CURRENTS within the environment of a CT SCANNER is intended to
ensure that ACCESSIBLE PARTS do not become live and to prevent interference in other electrical equipment.

The provision of a central PROTECTIVE EARTH TERMINAL is acceptable, as for fixed and PERMANENTLY INSTALLED
EQUIPMENT the interruption of the PROTECTIVE EARTH CONDUCTOR is not considered to be a SINGLE FAULT CONDITION.

However, in such cases, adequate information on the combination of ASSOCIATED EQUIPMENT needs to be provided

in accordance with 6.8.3 a).
Compliance is checked by inspection.
20 Dielectric strength
This clause of the General Standard applies except as follows:
20.3 Values of test voltages
Addition:
The dielectric strength of the electrical insulation of high-voltage circuits shall be sufficient to
withstand the test voltages for the durations given in 20.4 a).
The test shall be made without an X-RAY TUBE connected and with a test voltage of 1,2 times
the NOMINAL X-RAY TUBE VOLTAGE of the HIGH-VOLTAGE GENERATOR.
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.
20.4 Tests
Item a)
Addition:
The high-voltage circuits of HIGH-VOLTAGE GENERATORS or sub-assemblies thereof are tested

by applying a test voltage of 50 % of its final value according to 20.3 and raising it over a
period of 10 s or less to the final value, which then is maintained for 3 min.
If during the dielectric strength test there is a risk of overheating a transformer or associated
circuitry under test, it is permitted to carry out the test at a higher supply frequency or to
supply the test voltage to the secondary side by another generator.

60601-2-44 © IEC:2001+A1:2002(E) – 17 –

Item d)
Replacement:
During the dielectric strength test, the test voltage in the high-voltage circuit should be kept to

100 % to 105 % of the value required.

Item f)
Addition:
During the dielectric strength test of HIGH-VOLTAGE GENERATORS slight corona discharges in
the high-voltage circuit are to be disregarded if they cease when the test voltage is lowered
to 1,1 times the voltage to which the test condition is referred.
Item l)
Addition:
The test voltage for the dielectric strength testing of stator and stator circuits used for the
operation of the rotating ANODE of the X-RAY TUBE is to be referred to the voltage existing after
reduction of the stator supply voltage to its steady state operating value.
Additional item aa):
1) HIGH-VOLTAGE GENERATORS or sub-assemblies thereof that are integrated with an X-RAY
TUBE ASSEMBLY are to be tested with an appropriately loaded X-RAY TUBE.
2) If the dielectric strength test is performed with an X-RAY TUBE connected and the
high-voltage circuit is not accessible for the measurement of the test voltage applied,
appropriate measures are to be taken to ensure that the values lie within the limits
required in 20.4 d).
– 18 – 60601-2-44 © IEC:2001+A1:2002(E)

SECTION 4: PROTECTION AGAINST MECHANICAL HAZARDS

The clauses and subclauses of this section of the General Standard apply except as follows:

22 Moving parts
Subclause 22.4 of IEC 60601-2-32 applies except as follows:

Addition:
22.4.101 Gantry and PATIENT SUPPORT
a) General
1) Interruption or failure of powered movements or of the SUPPLY MAINS shall cause any
parts in motion to be stopped within the limits given in items b) and c). The maximum
value of distance and angle for each stopping condition shall be given in the
ACCOMPANYING DOCUMENTS.
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS and by interruption of
the SUPPLY MAINS to powered movements and measurement of stopping distances. These
tests shall be performed with a PATIENT-equivalent mass of 135 kg distributed evenly over the
PATIENT SUPPORT.
2) When a part is provided with one or several devices designed to reduce, in NORMAL
USE, the risk of collision with the PATIENT, the operation and limitations of each device
shall be described in the INSTRUCTIONS FOR USE.
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS.
3) Where there is a possibility that a failure of a powered movement during NORMAL USE of
the EQUIPMENT might result in the PATIENT being trapped, controls and switches shall
be provided to permit the release of the PATIENT. These means shall be described in
the INSTRUCTIONS FOR USE and on a label on the EQUIPMENT when a deliberate action is
required.
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS.
b) Tilting of the gantry
When the emergency stop control is actuated, the gantry tilt shall stop within an angle of 0,5°.
Compliance is checked by inspection.

c) Linear movements of the PATIENT SUPPORT
When the emergency stop control is actuated, the PATIENT SUPPORT shall stop within a
distance of 10 mm.
Compliance is checked by inspection.
22.4.102 Operation of EQUIPMENT movements from inside the RADIATION room
Any motorized movements of equipment parts which may cause physical injury to the PATIENT
shall be controlled by continuous deliberate action by the OPERATOR.

60601-2-44 © IEC:2001+A1:2002(E) – 19 –

The control shall be located close to the PATIENT SUPPORT so that the OPERATOR can
continuously observe the PATIENT and thus avoid possible injury to the latter and be

positioned in such a way that it cannot easily be touched by the PATIENT.

22.4.103 Operation of EQUIPMENT movements from outside the RADIATION room

Any motorized movements of equipment parts which may cause physical injury to the PATIENT
shall be controlled by continuous deliberate action by the OPERATOR. Those movements which

are part of a pre-programmed scanning protocol are exempt from this requirement.

Subclause 22.7 of IEC 60601-1 applies except as follows:

Addition:
22.7.101 Emergency stop of motorized movements
Readily identifiable and accessible controls and switches shall be provided in hard-wired
circuits near to, or on, the PATIENT SUPPORT and/or gantry, for emergency stopping of all
motorized movements by interruption of the SUPPLY MAINS to the movement system. When
operated, any movement shall stop within the limits given in 22.4.101. These controls and
switches shall be positioned in such a way that they cannot be operated accidentally.
Similar controls shall also be provided near to, or on, any remote CONTROL PANEL from which
movements can be actuated.
The time to effect the disconnection of the SUPPLY MAINS after initiation by the controls and
switches shall not exceed 0,5 s.
NOTE The controls provided for emergency stopping of all motorized movements by interruption of the SUPPLY
MAINS to the movement system should also terminate LOADING as described in 29.1.101. Both controls may be the
same emergency stop button.
Compliance is checked by inspection and measurement of stopping distances and
disconnection time.
27 Pneumatic and hydraulic power
This clause of the General Standard applies except as follows:
Addition:
27.101 Variations of PRESSURE in PRESSURE-powered movements of CT SCANNERS
If a hazardous situation can arise from a change in the PRESSURE of a system used to provide
power for movements, all movements shall stop within the limits specified in 22.4.101.
Compliance is checked by simulation of a fault condition, the operation of protective devices
and measurement of stopping distances.

– 20 – 60601-2-44 © IEC:2001+A1:2002(E)

SECTION 5: PROTECTION AGAINST HAZARDS FROM UNWANTED OR

EXCESSIVE RADIATION
The clauses and subclauses of this section of the General Standard apply except as follows:

29 X-RADIATION
This clause of the General Standard applies except as follows:

Additional subclauses:
29.1.101 Emergency termination of X-RADIATION
Readily identifiable and accessible means shall be provided in hard-wired circuits near to, or
on, the PATIENT SUPPORT and/or the gantry for emergency interruption to terminate LOADING.
NOTE The means provided for emergency interruption of all SUPPLY MAINS to terminate LOADING should also stop
all movements as described in 22.4.101 b), 22.4.101 c) and 22.7.101. Both means may be the same emergency
stop button.
Compliance is checked by the appropriate functional tests.
29.1.101.1 Indication of operational states
a) READY STATE
Visible indication shall be provided on the CONTROL PANEL indicating the state when one
further actuation of a control from that CONTROL PANEL will initiate the LOADING of the X-RAY
TUBE.
If this state is indicated by means of a single-function indicator light, the colour green shall be
used; see 6.7 a).
Means shall be provided for a connection to enable this state to be indicated remotely from
the CONTROL PANEL. This requirement does not apply for MOBILE EQUIPMENT.
b) LOADING STATE
The LOADING STATE shall be indicated by a yellow indicator light on the CONTROL PANEL of the
CT system; see 6.7 a).
Compliance is checked b
...