SIST EN 61223-3-5:2005
(Main)Evaluation and routine testing in medical imaging departments -- Part 3-5: Acceptance tests - Imaging performance of computed tomography X-ray equipment
Evaluation and routine testing in medical imaging departments -- Part 3-5: Acceptance tests - Imaging performance of computed tomography X-ray equipment
This standard - defines the essential parameters which describe the performance of the CT scanners with regard to image quality, patient dose and positioning; - defines the methods of testing the essential parameters; - evaluates compliance with the tolerances of the parameters specified by the accompanying documents. These methods rely mainly on non-invasive measurements, using appropriate test equipment, performed during the installation or after it has been completed. Signed statements covering steps in the installation procedure may be used as part of the acceptance test report. This part of EN 61223 is intended to assist in performing the acceptance tests on a CT scanner. The aim is to verify compliance of the installation with specifications affecting the image quality, patient dose and positioning.
Bewertung und routinemäßige Prüfung in Abteilungen für medizinische Bildgebung -- Teil 3-5: Abnahmeprüfungen - Leistungsmerkmale zur Bildgebung von Röntgeneinrichtungen für Computertomographie
Essais d'évaluation et de routine dans les services d'imagerie médicale -- Partie 3-5: Essais d'acceptation - Performance d'imagerie des équipements de tomodensitométrie à rayonnement X
Cette norme - définit les paramètres importants qui décrivent les performances des tomodensitomètres en ce qui concerne la qualité d'image, la dose délivrée au patient et le positionnement; - définit les méthodes d'essais des paramètres importants; - évalue la conformité des paramètres par rapport aux tolérances spécifiées dans les documents d'accompagnement. Ces méthodes s'appuient principalement sur des mesures non invasives, exécutées pendant l'installation ou à l'issue de celle-ci, en utilisant les équipements d'essai appropriés. Des déclarations signées couvrant des étapes de la procédure d'installation peuvent être utilisées dans le cadre du rapport d'essai d'acceptation. La présente partie de la EN 61223 est destinée à aider à la réalisation des essais d'acceptation d'un tomodensitomètre. Le but est de vérifier la conformité de l'installation aux spécifications concernant la qualité de l'image, la dose délivrée au patient et lepositionnement.
Ovrednotenje in rutinsko preskušanje v medicinskih oddelkih za slikanje – 3-5. del: Preskusi sprejemljivosti – Slikovni učinek rentgenske opreme za računalniško podprto tomografijo
General Information
Relations
Standards Content (Sample)
SLOVENSKI SIST EN 61223-3-5:2005
STANDARD
januar 2005
Ovrednotenje in rutinsko preskušanje v medicinskih oddelkih za slikanje – 3-
5. del: Preskusi sprejemljivosti – Slikovni učinek rentgenske opreme za
računalniško podprto tomografijo
(istoveten EN 61223-3-5:2004)
Evaluation and routine testing in medical imaging departments - Part 3-5:
Acceptance tests - Imaging performance of computed tomography X-ray equipment
ICS 11.040.50 Referenčna številka
SIST EN 61223-3-5:2005(en)
© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno
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EUROPEAN STANDARD EN 61223-3-5
NORME EUROPÉENNE
EUROPÄISCHE NORM September 2004
ICS 11.040.50
English version
Evaluation and routine testing in medical imaging departments
Part 3-5: Acceptance tests –
Imaging performance of computed tomography X-ray equipment
(IEC 61223-3-5:2004)
Essais d'évaluation et de routine Bewertung und routinemäßige Prüfung in
dans les services d'imagerie médicale Abteilungen für medizinische Bildgebung
Partie 3-5: Essais d'acceptation – Teil 3-5: Abnahmeprüfungen –
Performance d'imagerie des équipements Leistungsmerkmale zur Bildgebung
de tomodensitométrie à rayonnement X von Röntgeneinrichtungen für
(CEI 61223-3-5:2004) Computertomographie
(IEC 61223-3-5:2004)
This European Standard was approved by CENELEC on 2004-09-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61223-3-5:2004 E
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EN 61223-3-5:2004 - 2 -
Foreword
The text of document 62B/525/FDIS, future edition 1 of IEC 61223-3-5, prepared by SC 62B,
Diagnostic imaging equipment, of IEC TC 62, Electrical equipment in medical practice, was submitted
to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61223-3-5 on 2004-09-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2005-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2007-09-01
In this standard, the following print types are used:
– requirements, compliance with which can be tested, and definitions: in roman type;
– explanations, advice, notes, general statements, exceptions and references: in smaller type;
– test specifications: in italic type;
– TERMS DEFINED IN EN 60601-1, EN 60788, EN 61223-1 OR IN OTHER STANDARDS REFERENCED IN
ANNEX A: SMALL CAPITALS.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61223-3-5:2004 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 61223-2-4 NOTE Harmonized as EN 61223-2-4:1994 (not modified).
IEC 61223-2-6 NOTE Harmonized as EN 61223-2-6:1994 (not modified).
IEC 60336 NOTE Harmonized as EN 60336:1995 (not modified).
IEC 60522 NOTE Harmonized as EN 60522:1999 (not modified).
IEC 60601-2-28 NOTE Harmonized as EN 60601-2-28:1993 (not modified).
IEC 60601-2-32 NOTE Harmonized as EN 60601-2-32:1994 (not modified).
IEC 61267 NOTE Harmonized as EN 61267:1994 (not modified).
__________
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- 3 - EN 61223-3-5:2004
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60601-1 - Medical electrical equipment EN 60601-1 1990
Part 1: General requirements for safety
IEC 60601-2-44 2001 Part 2-44: Particular requirements for the EN 60601-2-44 2001
safety of X-ray equipment for computed
tomography
A1 2002 A1 2003
1)
IEC/TR 60788 - Medical electrical equipment - Glossary of - -
defined terms
1)
Undated reference.
2)
Valid edition at date of issue.
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NORME CEI
INTERNATIONALE IEC
61223-3-5
INTERNATIONAL
Première édition
STANDARD
First edition
2004-08
Essais d'évaluation et de routine
dans les services d'imagerie médicale –
Partie 3-5:
Essais d'acceptation –
Performance d'imagerie des équipements
de tomodensitométrie à rayonnement X
Evaluation and routine testing
in medical imaging departments –
Part 3-5:
Acceptance tests –
Imaging performance of computed
tomography X-ray equipment
” IEC 2004 Droits de reproduction réservés Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
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Commission Electrotechnique Internationale PRICE CODE
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
Pour prix, voir catalogue en vigueur
For price, see current catalogue
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61223-3-5 ” IEC:2004 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.9
1 Scope and object.11
2 Normative references.11
3 Terms and definitions .13
4 General aspects of ACCEPTANCE TESTS .23
4.1 General conditions to be considered in test procedures .23
4.2 Documents and data for the tests.23
4.3 Identification of EQUIPMENT, instrumentation and test conditions.23
4.4 Scope of tests.25
4.5 Test EQUIPMENT, including PHANTOMS and TEST DEVICES .25
5 Test methods for CT SCANNERS .27
5.1 Positioning of the PATIENT SUPPORT .27
5.2 PATIENT positioning accuracy.29
5.3 TOMOGRAPHIC SECTION THICKNESS .33
5.4 Dose.35
5.5 NOISE, MEAN CT NUMBER and UNIFORMITY .37
5.6 SPATIAL RESOLUTION .41
Annex A (normative) Terminology – Index of defined terms.43
Annex B (informative) Recommended criteria for test results .47
Annex C (informative) Visual Method for LOW CONTRAST RESOLUTION .49
Annex D (informative) Accuracy of the gantry tilt .51
Annex E (informative) DOSE PROFILE.53
Annex F (informative) Alternate test methods for SPATIAL RESOLUTION.55
Annex G (informative) TOMOGRAPHIC SECTION THICKNESS for helical scanning.61
Bibliography .63
Figure 1 – Coordinate system .19
Table 1 Test pattern for dose .37
Table F.1 Comparison of SPATIAL RESOLUTION test procedures.55
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61223-3-5 ” IEC:2004 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
EVALUATION AND ROUTINE TESTING
IN MEDICAL IMAGING DEPARTMENTS –
Part 3-5: Acceptance tests –
Imaging performance of computed tomography
X-ray equipment
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61223-3-5 has been prepared by subcommittee 62B: Diagnostic
imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice.
The text of this standard is based on the following documents:
FDIS Report of voting
62B/525/FDIS 62B/544/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.
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61223-3-5 ” IEC:2004 – 7 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 61223-3 includes the following parts, under the general title Evaluation and routine
testing in medical imaging departments – Part 3: Acceptance tests:
Part 3-1: Imaging performance of X-ray equipment for radiographic and radioscopic systems
Part 3-2: Imaging performance of mammographic X-ray equipment
Part 3-3: Imaging performance of X-ray equipment for digital subtraction angiography (DSA)
Part 3-4: Imaging performance of dental X-ray equipment
Part 3-5: Imaging performance of computed tomography X-ray equipment
In this standard, the following print types are used:
– requirements, compliance with which can be tested, and definitions: in roman type;
– explanations, advice, notes, general statements, exceptions and references: in smaller type;
– test specifications and headings of subclauses: in italic type;
– TERMS DEFINED IN IEC 60601-1, IEC60788, IEC61223-1 OR IN OTHER IEC PUBLICATIONS
REFERENCED IN ANNEX A: SMALL CAPITALS.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
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61223-3-5 ” IEC:2004 – 9 –
INTRODUCTION
This International Standard forms part of the IEC 61223 series, which gives methods of
acceptance testing and constancy testing for medical diagnostic X-RAY EQUIPMENT.
The ACCEPTANCE TEST is carried out after new EQUIPMENT has been installed, or major
modifications have been made to existing EQUIPMENT, in order to facilitate verification of
applicable safety and performance standards, regulations, and contractual specifications
which influence the image quality, PATIENT dose and positioning.
To maintain the homogeneity of this IEC standard with the other two IEC standards
addressing CT SCANNERS, the measuring methods and the terminology are taken as
applicable from
– the CT safety standard IEC 60601-2-44, and
1)
– the CT constancy testing standard IEC 61223-2-6 >3@
Some provisions or statements in this standard require additional information. Additional
information is presented in the annexes. An asterisk in the left margin of a clause or
subclause indicates the presence of such additional information.
———————
1)
Figures in square brackets refer to the bibliography.
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61223-3-5 ” IEC:2004 – 11 –
EVALUATION AND ROUTINE TESTING
IN MEDICAL IMAGING DEPARTMENTS –
Part 3-5: Acceptance tests –
Imaging performance of computed tomography
X-ray equipment
1 Scope and object
This part of IEC 61223 applies to those components of CT SCANNERS which influence the
image quality, PATIENT dose and positioning.
This standard
– defines the essential parameters which describe the performance of the CT SCANNERS with
regard to image quality, PATIENT dose and positioning; the list of parameters to be tested
can be found in section 4.4.
– defines the methods of testing the essential parameters;
– evaluates compliance with the tolerances of the parameters specified by the
ACCOMPANYING DOCUMENTS.
These methods rely mainly on non-invasive measurements, using appropriate test EQUIPMENT,
performed during the installation or after it has been completed. Signed statements covering
steps in the installation procedure may be used as part of the ACCEPTANCE TEST report.
This part of IEC 61223 is intended to assist in performing the ACCEPTANCE TESTS on a CT
SCANNER The aim is to verify compliance of the installation with specifications affecting the
image quality, PATIENT dose and positioning.
It is not intended to consider:
– aspects of mechanical and electrical safety;
– aspects of mechanical, electrical and software performance, unless they are essential for
performing the ACCEPTANCE TESTS and are directly affecting image quality, PATIENT dose
and positioning.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
2)
IEC 60601-1, Medical electrical equipment – Part 1: General requirements for safety
IEC 60601-2-44:2001, Medical electrical equipment – Part 2-44: Particular requirements for
3)
the safety of X-ray equipment for computed tomography
Amendment 1 (2002)
IEC 60788, Medical electrical equipment – Glossary of defined terms
———————
2)
The new edition of IEC 60601-1 (to be published) will be entitled: Medical electrical equipment – Part 1: General
requirements for basic safety and essential performance
3) There exists a consolidated edition 2.1 (2002) including Edition 2 (2001) and its Amendment 1 (2002)
---------------------- Page: 10 ----------------------
61223-3-5 ” IEC:2004 – 13 –
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE 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 2 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.
NOTE 3 An index of defined terms used in this standard is given in Annex A.
NOTE 4 Associated conditions qualifying the usage of certain terms are given below.
3.1
ACCEPTANCE TEST
test carried out after new EQUIPMENT has been installed, or major modifications have been
made to existing EQUIPMENT, in order to verify compliance with contractual specifications
[IEC 61223-1:1993, definition 3.2.4] [1]
3.2
CONSTANCY TEST
each of a series of tests carried out to ensure that the functional performance of EQUIPMENT
meets established criteria; or to enable the early recognition of changes in the properties of
components of the EQUIPMENT
[IEC 61223-1:1993, definition 3.2.6]
3.3
CT CONDITIONS OF OPERATION
all selectable parameters governing the operation of a CT SCANNER, for example NOMINAL
TOMOGRAPHIC SECTION THICKNESS, CT PITCH FACTOR, filtration, peak X-RAY TUBE VOLTAGE and
either X-RAY TUBE CURRENT and LOADING TIME or CURRENT TIME PRODUCT
[IEC 60601-2-44, definition 2.102]
3.4
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.
[IEC 60601-2-44, definition 2.101]
3.5
COMPUTED TOMOGRAPHY DOSE INDEX 100
CTDI
100
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
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61223-3-5 ” IEC:2004 – 15 –
+50 mm
D (z)
= dz
CTDI
100
³
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
100
4)
integrated from –7 T to +7 T 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
100
within a PMMA dosimetry PHANTOM is well approximated by measurement of the air kerma with an lionization
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.
[IEC 60601-2-44, definition 2.106]
3.6
WEIGHTED CTDI
100
weighted CTDI (CTDI ) defined as
w
1 2
CTDI CTDI CTDI
W 100(centre) 100(peripheral)
3 3
where
CTDI is the value measured in the centre of the test object, and
100(centre)
CTDI is the average value measured in the periphery of the test object.
100(peripheral)
3.7
COMPUTED TOMOGRAPHY NUMBER
CT NUMBER
number used to represent the mean X-ray ATTENUATION associated with each elemental area
of the COMPUTED TOMOGRAPHY image
NOTE The CT NUMBER is normally expressed in Hounsfield units. MEASURED VALUES of the linear ATTENUATION
coefficients are transformed into CT NUMBERS using the international Hounsfield scale, using the expression:
P P
material water
CT NUMBER of material ˜1 000
P
water
where
µ is the linear ATTENUATION coefficient.
The CT NUMBER scale is defined so that water has a value of 0 and air a value of 1 000.
[IEC 61223-2-6:1994, definition 3.3.2] [3]
———————
4)
U.S.Code of Federal Regulations, Title 21, Chapter 1: Food and Drug Administration (FDA), Part 1020 –
Performance standards for ionizing radiation emitting products: Section 1020.33: Computed tomography (CT)
equipment
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61223-3-5 ” IEC:2004 – 17 –
3.8
DOSE PROFILE
representation of the dose as a function of position along a line
[60601-2-44, definition 2.103]
3.9
FULL WIDTH AT HALF-MAXIMUM
FWHM
interval parallel to the abscissa between the points on a curve with the value of one-half of the
maximum of the curve
[IEC 61223-2-6:1994, definition 3.3.4]
3.10
IMAGE DISPLAY DEVICE
device capable of displaying images from an input signal provided by an imaging system
3.11
LOW CONTRAST RESOLUTION
lowest contrast detail of an object of a SPECIFIED shape and area that can be resolved from a
uniform background
3.12
MEAN CT NUMBER
mean value of the CT NUMBERS of all pixels within a certain defined REGION OF INTEREST
[IEC 61223-2-6:1994, definition 3.3.6]
3.13
NOISE
variation of CT NUMBERS from a mean value in a defined area in the image of a uniform
substance.
The magnitude of NOISE is indicated by the standard deviation of the CT NUMBERS of a uniform
substance in the REGION OF INTEREST
[IEC 61223-2-6:1994, definition 3.3.7]
3.14
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.
[60601-2-44, definition 2.110]
3.15
REGION OF INTEREST
ROI
localised part of an image, which is of particular interest at a given time
[IEC 61223-2-6:1994, definition 3.3.9]
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61223-3-5 ” IEC:2004 – 19 –
3.16
SENSITIVITY PROFILE
relative response of a system for COMPUTED TOMOGRAPHY as a function of position along a line
perpendicular to the TOMOGRAPHIC PLANE
[source 60601-2-44, definition 2.104]
3.17
SPATIAL RESOLUTION
in EQUIPMENT for COMPUTED TOMOGRAPHY, the ability to resolve different objects in the
displayed image, when the difference in ATTENUATION between the objects and the
background is large compared to NOISE
NOTE 1 Normally a difference in ATTENUATION coefficient between the object and the background resulting in a
difference of the respective CT NUMBERS of several hundred Hounsfield units is regarded as large enough.
NOTE 2 high-contrast resolution is an alternative name for SPATIAL RESOLUTION.
[IEC 61223-2-6:1994, definition 3.3.12]
3.18
TOMOGRAPHIC PLANE
geometric plane perpendicular to the axis of rotation (see Figure 1)
y
1
T x
2
z
IEC 1069/04
Key
1 TOMOGRAPHIC PLANE
2 PHANTOM
Figure 1 – Coordinate system
3.19
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.
[source 60601-2-44, definition 2.108]
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61223-3-5 ” IEC:2004 – 21 –
3.20
TOMOGRAPHIC SECTION THICKNESS
FULL WIDTH AT HALF MAXIMUM of the SENSITIVITY PROFILE taken at the isocentre of a
TOMOGRAPHIC SECTION
[source 60601-2-44, definition 2.109]
3.21
UNIFORMITY
consistency of the CT NUMBERS of the image of a homogeneous material across the scan field
[IEC 61223-2-6:1994, definition 3.3.13]
3.22
CT PITCH FACTOR
in helical scanning the ratio of the PATIENT SUPPORT travel ǻd 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
'd 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.
[source 60601-2-44, definition 2.107]
3.23
VOLUMECTDI
W
CTDI
vol
average dose over the total volume scanned for the selected CT CONDITIONS OF OPERATION
The CTDI is defined as follows:
vol
a) for axial scanning
N ˜ T
CTDI ˜ CTDI
vol w
'd
where
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-RAY
SOURCE;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
ǻ d is the PATIENT SUPPORT travel in z-direction between consecutive scans.
CTDI is the weighted CTDI.
w
b) for helical scanning
CTDI
w
CTDI
vol
CT pitch factor
where CTDI is the weighted CTDI.
w
---------------------- Page: 15 ----------------------
61223-3-5 ” IEC:2004 – 23 –
3.24
CTDI
free air
CTDI measured at isocenter in the absence of a PHANTOM and the PATIENT SUPPORT
100
4 General aspects of ACCEPTANCE TESTS
4.1 General conditions to be considered in test procedures
The aim of an ACCEPTANCE TEST is to demonstrate that the SPECIFIED characteristics of the
EQUIPMENT lie within the SPECIFIED tolerances as stated in ACCOMPANYING DOCUMENTS.
An inventory of the EQUIPMENT under test and the ACCOMPANYING DOCUMENTS shall be
compiled before any ACCEPTANCE TESTS are carried out. Each item shall be identified by its
MODEL OR TYPE REFERENCE (type number) and SERIAL NUMBER, and the entire inventory shall be
compared with the purchase contract.
The performance of the IMAGE DISPLAY DEVICE will affect the measu
...
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