IEC 60601-2-44:1999

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

Establishes requirements for safe operation of X-ray equipment for computed tomography (CT scanners).

General Information

• Status: Published
• Publication Date: 09-Feb-1999
• ICS: 11.040.50 - Radiographic equipment
• Technical Committee: SC 62B - Medical imaging equipment, software, and systems
• Current Stage: DELPUB - Deleted Publication
• Start Date: 21-Jun-2001
• Completion Date: 26-Oct-2025

Relations

• Revised: IEC 60601-2-44:2001 - 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 60601-2-44:1999 is a Particular Standard of the IEC 60601 family that establishes safety requirements specifically for X‑ray equipment for computed tomography (CT scanners). It amends and supplements the General Standard (IEC 60601‑1) and relevant Collateral Standards to address hazards unique to CT systems, including X‑radiation control, mechanical safety of gantry and patient support, accuracy of operating data and documentation requirements.

Key topics and requirements

• Scope and objective: Applies to CT scanners (does not cover HV‑generators). Its purpose is to define requirements for safe operation not already covered by IEC 60601‑1 and Collateral Standards.
• Radiation protection and dosimetry:
  • Definitions and measurement concepts such as Dose Profile, Sensitivity Profile, Tomographic Section Thickness, CTDI100 and CT pitch factor are specified to standardize dose reporting and assessment.
  • CTDI100: a dose index derived from the dose profile integrated from –50 mm to +50 mm and normalized by the number of sections and nominal section thickness - used for CT dose characterization.
• Mechanical safety:
  • Requirements for gantry and patient support movements, including stopping behavior when mains or powered movements are interrupted. Tests use a patient‑equivalent mass of 135 kg.
  • Emergency stop limits are specified: gantry tilt must stop within 0.5° and patient support stop distance within 10 mm.
  • Controls for motorized movements inside the radiation room must be under continuous deliberate operator action to avoid injury.
• Identification, marking and documentation:
  • Accompanying documents and an explicit site test report are required when on‑site modifications (e.g., emergency switching of supply mains) are implemented.
  • Instructions must describe safety device operation and limits.
• Operational definitions: Standardizes terminology (e.g., CT scanner, tomographic plane, section thickness) to ensure consistent interpretation across manufacturers and test labs.

Practical applications and users

IEC 60601-2-44 is used by:

• CT manufacturers for design, risk mitigation and compliance testing of hardware, controls and dosimetry.
• Test laboratories and notified bodies for type testing and certification against CT‑specific safety criteria.
• Clinical engineers and hospital procurement teams to evaluate equipment safety, site installation requirements and acceptance testing (site test reports).
• Regulators and standards committees for harmonized radiation and mechanical safety expectations.

Related standards

• IEC 60601‑1 (General requirements for safety) and Collateral Standards (e.g., IEC 60601‑1‑2 EMC, IEC 60601‑1‑3 radiation protection, IEC 60601‑1‑4 software)
• IEC 60601‑2‑32 (associated X‑ray equipment)
• IEC 60788 (medical radiology terminology)
• ISO 2092 (designation of light metals)

Standards Content (Sample)

INTERNATIONAL
IEC
STANDARD
60601-2-44
First edition
1999-02
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
Numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series.
Consolidated publications
Consolidated versions of some IEC publications including amendments are

available. 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.

Validity of this publication
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 the date of the reconfirmation of the publication is available
in the IEC catalogue.
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 of
publications issued, is to be found at the following IEC sources:
• IEC web site*
• Catalogue of IEC publications
Published yearly with regular updates
(On-line catalogue)*
• IEC Bulletin
Available both at the IEC web site* and as a printed periodical
Terminology, graphical and letter symbols
For general terminology, readers are referred to IEC 60050: International
Electrotechnical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for
general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols
for diagrams.
* See web site address on title page.

INTERNATIONAL
IEC
STANDARD
60601-2-44
First edition
1999-02
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 1999  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
R
International Electrotechnical Commission
For price, see current catalogue

– 2 – 60601-2-44 © IEC:1999(E)

CONTENTS
Page
FOREWORD . 3

INTRODUCTION .4

Clause
SECTION 1: GENERAL
1 Scope and object .5

2 Terminology and definitions. 6
6 Identification, marking and documents. 8
SECTION 2: ENVIRONMENTAL CONDITIONS
SECTION 3: PROTECTION AGAINST ELECTRIC SHOCK HAZARDS
SECTION 4: PROTECTION AGAINST MECHANICAL HAZARDS
22 Moving parts.9
27 Pneumatic and hydraulic power . 10
SECTION 5: PROTECTION AGAINST HAZARDS FROM UNWANTED
OR EXCESSIVE RADIATION
29 X-RADIATION. 11
SECTION 6: PROTECTION AGAINST HAZARDS OF IGNITION OF
FLAMMABLE ANAESTHETIC MIXTURES
SECTION 7: PROTECTION AGAINST EXCESSIVE TEMPERATURES
AND OTHER SAFETY HAZARDS
SECTION 8: ACCURACY OF OPERATING DATA AND PROTECTION
AGAINST HAZARDOUS OUTPUT
50 Accuracy of operating data . 17

SECTION 9: ABNORMAL OPERATION AND FAULT CONDITIONS;
ENVIRONMENTAL TESTS
SECTION 10: CONSTRUCTIONAL REQUIREMENTS
Table 101 – HALF-VALUE LAYERS in CT SCANNERS . 15
Figure 101 – Coordinate system . 7
Annex AA (normative) Terminology – Index of defined terms. 18

60601-2-44 © IEC:1999(E) – 3 –

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 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.
The text of this Particular Standard is based on the following documents:
FDIS Report on voting
62B/360/FDIS 62B/364/RVD
Full information on the voting for the approval of this Particular Standard can be found in the
report on voting indicated in the above table.
Annex AA forms an integral part of this standard.
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: small roman type;
– test specifications: italic type;
– TERMS DEFINED IN CLAUSE 2 OF THE GENERAL STANDARD OR OF THIS PARTICULAR STANDARD OR
IN SMALL CAPITALS
IEC 60788: .
A bilingual version of this Standard may be issued at a later date.

– 4 – 60601-2-44 © IEC:1999(E)

INTRODUCTION
The relationship of this Particular Standard with IEC 60601-1 (including the amendments) and

the Collateral Standards is explained in 1.3.

60601-2-44 © IEC:1999(E) – 5 –

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 does not cover the safety requirements for HV-generators which will be the
subject of another standard.
1.2 Object
Replacement:
The object of this standard is to establish requirements for safe operation of CT SCANNERS in
as far as those requirements have not yet been specified in the General Standard, the
Collateral Standards or other Particular Standards.
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 1 (1991) and 2 (1995), and any Collateral Standard.

The numbering of sections, clauses and subclauses of this Particular 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 Particular Standard.
– "Addition" means that the text of this Particular 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 Particular Standard.
Subclauses, figures or tables 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 Particular Standard, the
section, clause or subclause of the General Standard applies without modification.

– 6 – 60601-2-44 © IEC:1999(E)

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 Particular Standard.

A requirement of this Particular Standard replacing or modifying requirements of the General

Standard takes precedence over the original requirements concerned.

1.3.101 Related international standards

IEC 60601-1-1:1992, Medical electrical equipment – Part 1: General requirements for safety –

1. Collateral Standard: Safety requirements for medical electrical systems

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
IEC 60601-1-4:1996, Medical electrical equipment – Part 1: General requirements for safety –
4. Collateral Standard: Programmable electrical medical systems
IEC 60601-2-32:1994, Medical electrical equipment – Part 2: Particular requirements for the
safety of associated equipment of X-ray equipment
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:
2.101 Definitions
In this Particular Standard, terms printed in SMALL CAPITALS are used in accordance with their
definitions in the General Standard, in this standard or in IEC 60788.

An index of defined terms used in this Particular Standard is given in annex AA.
Additional definitions:
2.101.1
CT SCANNER
X-RAY EQUIPMENT for COMPUTED TOMOGRAPHY
2.101.2
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:1999(E) – 7 –

y
T x
z
1 TOMOGRAPHIC PLANE
2 PHANTOM
IEC  210/99
Figure 101 – Coordinate system
2.101.3
DOSE PROFILE
representation of the dose as a function of position along a line
2.101.4
SENSITIVITY PROFILE
relative response of a system for COMPUTED TOMOGRAPHY as a function of position along a line
perpendicular to the TOMOGRAPHIC PLANE
2.101.5
TOMOGRAPHIC PLANE
geometric plane defined by the FOCAL SPOT and perpendicular to the axis of rotation; see
figure 101
2.101.6
COMPUTED TOMOGRAPHY DOSE INDEX 100 (CTDI )
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 360° rotation of the RADIATION SOURCE and the NOMINAL TOMOGRAPHIC
SECTION THICKNESS T in a single rotation of the RADIATION SOURCE

+50 mm
Dz
()
CTDI = dz
∫
NT×
− 50 mm
where
D(z) is the DOSE PROFILE along a line z perpendicular to the TOMOGRAPHIC PLANE, where dose
is measured as ABSORBED DOSE to air;
N is the number of TOMOGRAPHIC SECTIONS produced in a single rotation of the RADIATION
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
integrated from –7T to +7T as defined by the FDA in 21 CFR Ch. I § 1020.33.

– 8 – 60601-2-44 © IEC:1999(E)

NOTE 2 – Dose is calculated 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).

NOTE 3 – When the RADIATION SOURCE rotation is limited to less than 360°, the CTDI should be scaled
accordingly.
NOTE 4 – 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 and for
helical scans the CT PITCH FACTOR is equal to 1.

2.101.7
CT PITCH FACTOR
ratio of the PATIENT SUPPORT travel in the horizontal direction per rotation of the X-RAY TUBE
divided by the product of the number N of TOMOGRAPHIC SECTIONS irradiated simultaneously by
the X-RAY TUBE, and the NOMINAL TOMOGRAPHIC SECTION THICKNESS .
T
Δd
CT pitch factor =
NT×
where:
Δd is the PATIENT SUPPORT travel in horizontal direction;
N is the number of TOMOGRAPHIC SECTIONS produced by a single rotation of the X-RAY TUBE;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS.
2.101.8
TOMOGRAPHIC SECTION
volume of an object in which the properties of ATTENUATION of X-RADIATION are imaged
2.101.9
TOMOGRAPHIC SECTION THICKNESS
FULL WIDTH AT HALF MAXIMUM of the SENSITIVITY PROFILE taken at the centre of the cross-
sectional volume over which TRANSMISSION data of X-RADIATION are collected
2.101.10
NOMINAL TOMOGRAPHIC SECTION THICKNESS
in CT SCANNERS the TOMOGRAPHIC SECTION THICKNESS which is selected and indicated on the
CONTROL PANEL
2.202 Qualifying conditions for defined terms
This subclause of the General Standard does not apply.

6 Identification, marking and documents
This clause of the General Standard applies, except as follows:
6.8 ACCOMPANYING DOCUMENTS
Additional subclause:
6.8.101 Site test report
When means for emergency switching of the SUPPLY MAINS are to be incorporated on site by
the USER, the requirements and site test procedures shall be specified in the ACCOMPANYING
DOCUMENTS. The test results should be incorporated in the site test report.

60601-2-44 © IEC:1999(E) – 9 –

SECTION 2: ENVIRONMENTAL CONDITIONS

The clauses and subclauses of this section of the General Standard apply.

SECTION 3: PROTECTION AGAINST ELECTRIC SHOCK HAZARDS

The clauses and subclauses of this section of the General Standard apply.

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:
Additional subclauses:
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.

– 10 – 60601-2-44 © IEC:1999(E)

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.

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:
Additional subclause:
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 29.101. Both controls may be the
same emergency stop button.
Compliance is checked by inspection and measurement of stopping distances and dis-
connection time.
27 Pneumatic and hydraulic power

This clause of the General Standard applies, except as follows:
Replacement:
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:1999(E) – 11 –

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 Collateral Standard IEC 60601-1-3 applies, except as follows:

Additional subclauses:
29.101 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 of all SUPPLY MAINS 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.
29.102 Dose statements and test equipment
29.102.1 Dose statements
The following dose information shall be obtained by using the dosimetry PHANTOM for
COMPUTED TOMOGRAPHY. For any CT SCANNER designed to image both the head and body,
separate dose information shall be provided for each application in the ACCOMPANYING
DOCUMENTS. All dose measurements shall be performed with the PHANTOM specified in 29.102.2
placed on the PATIENT SUPPORT without additional attenuating material present. This dosimetry
PHANTOM shall be centred in the scanfield and on the axis of rotation of the scanner.
The following information shall be given in the ACCOMPANYING DOCUMENTS:
CONDITIONS OF OPERATION
a) The CTDI and the corresponding CT at the following locations
in the dosimetry using the PHANTOM specified in 29.102.2:
1) Along the axis of rotation of the PHANTOM (CTDI centre value).
2) Along a line parallel to the axis of rotation and 10 mm interior to the surface of the
PHANTOM with the PHANTOM positioned so that the CTDI is the maximum obtainable at
this depth (CTDI peripheral value).
3) Along a line parallel to the axis of rotation and 10 mm interior to the surface of the
PHANTOM at positions 90°, 180° and 270° from the position in item a) 2) of this
subclause. The CT CONDITIONS OF OPERATION shall be the typical values suggested by
the MANUFACTURER. The location of the position where the CTDI is maximum as
specified in item a) 2) of this subclause shall be given by the MANUFACTURER with
respect to the housing of the scanning mechanism or other readily identifiable part of
the CT SCANNER in such a manner as to permit placement of the dosimetry PHANTOM in
this orientation.
b) The CTDI in the centre location of the dosimetry PHANTOM for each selectable
CT CONDITION OF OPERATION that varies either the rate or duration of IRRADIATION or the
NOMINAL TOMOGRAPHIC SECTION THICKNESS. This CTDI shall be presented as a value that
is normalized to the CTDI in the centre location of the dosimetry PHANTOM from item a)
of this subclause, with the CTDI of item a) of this subclause having a value of 1. As a
single CT CONDITION OF OPERATION is changed, all other independent CT CONDITIONS OF
OPERATION shall be maintained at the typical values described in item a) of this subclause.
These data shall encompass the range of each CT CONDITION OF OPERATION stated by the
MANUFACTURER as appropriate. When more than three selections of a CT CONDITION OF

– 12 – 60601-2-44 © IEC:1999(E)

OPERATION are available, the normalized CTDI shall be provided, at least for the
minimum, maximum and one midrange value of the CT CONDITION OF OPERATION.

c) The CTDI at the location coincident with the maximum CTDI at 10 mm interior to the

100 100
surface of the dosimetry PHANTOM for each selectable peak X-RAY TUBE VOLTAGE. When

more than three selections of the peak X-RAY TUBE VOLTAGE are available, the normalized

CTDI shall be provided, at least for the minimum, maximum and one midrange value of
the peak X-RAY TUBE VOLTAGE. The CTDI shall be presented as a value that is
normalized to the maximum CTDI located at 10 mm interior to the surface of the
dosimetry PHANTOM from item a) above, with the CTDI of item a) above having a value
of 1.
d) A statement of the maximum deviation from the values given according to items a), b)

and c). Deviation of values shall not exceed these limits.
29.102.2 Dosimetry PHANTOM
The dosimetry PHANTOM shall consist of PMMA cylinders of diameter 160 mm for head
techniques and 320 mm for body techniques. The length of the PHANTOM shall be at least 140
mm. The PHANTOM shall be longer than the SENSITIVE VOLUME of the RADIATION DETECTOR used
for the measurements. The PHANTOM shall contain holes just large enough to accept the
RADIATION DETECTOR. These holes shall be parallel to the axis of symmetry of the PHANTOM and
the centres of the holes shall be located at the centre and 10 mm below the surface of the
PHANTOM
at 90° intervals.
For the holes not used during a measurement, properly fitting insert parts of the same material
as the P
...