IEC 60601-2-44:2009/AMD1:2012
(Amendment)Amendment 1 - Medical electrical equipment - Part 2-44: Particular requirements for the basic safety and essential performance of X-ray equipment for computed tomography
Amendment 1 - Medical electrical equipment - Part 2-44: Particular requirements for the basic safety and essential performance of X-ray equipment for computed tomography
Amendement 1 - Appareils électromédicaux - Partie 2-44: Exigences particulières pour la sécurité de base et les performances essentielles des équipements à rayonnement X de tomodensitométrie
S'applique aux résistances fixes de dissipation supérieure à 1 W et inférieure à 1 000 W, pourvues d'un revêtement protecteur. Prescrit les valeurs préférentielles de caractéristiques. Choisit, dans la CEI 115-1, les procédures d'assurance de la qualité et les méthodes d'essai et de mesure appropriées. Fixe les exigences générales.
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IEC 60601-2-44 ®
Edition 3.0 2012-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
AMENDMENT 1
AMENDEMENT 1
Medical electrical equipment –
Part 2-44: Particular requirements for the basic safety and essential performance
of X-ray equipment for computed tomography
Appareils électromédicaux –
Partie 2-44: Exigences particulières pour la sécurité de base et les performances
essentielles des équipements à rayonnement X de tomodensitométrie
IEC 60601-2-44:2009/A1:2012
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IEC 60601-2-44 ®
Edition 3.0 2012-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
AMENDMENT 1
AMENDEMENT 1
Medical electrical equipment –
Part 2-44: Particular requirements for the basic safety and essential performance
of X-ray equipment for computed tomography
Appareils électromédicaux –
Partie 2-44: Exigences particulières pour la sécurité de base et les performances
essentielles des équipements à rayonnement X de tomodensitométrie
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 11.040.50 ISBN 978-2-83220-304-0
– 2 – 60601-2-44 Amend.1 © IEC:2012
FOREWORD
This amendment has been prepared by subcommittee SC 62B: Diagnostic imaging equipment,
of IEC Technical Committee 62: Electrical equipment in medical practice.
The text of this amendment is based on the following documents:
FDIS Report on voting
62B/879/FDIS 62B/890/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
NOTE The attention of National Committees is drawn to the fact that equipment MANUFACTURERS and testing
organizations may need a transitional period following publication of a new, amended or revised IEC publication in
which to make products in accordance with the new requirements and to equip themselves for conducting new or
revised tests. It is the recommendation of the committee that the content of this publication be adopted for
implementation nationally not earlier than 3 years from the date of publication.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
_____________
60601-2-44 Amend.1 © IEC:2012 – 3 –
Introduction to Amendment 1
The main topic addressed in this amendment is an extended concept of CTDI to
accommodate CT SCANNERS with very large z-coverage. The other principal subject areas
include:
1) a dose-check feature associated with a pre-scanning alert if expected values of dose
DOSE NOTIFICATION VALUES or DOSE ALERT VALUES and
indices exceed user-configurable
2) requirements covering the use of CT data in radiotherapy treatment planning (RTP).
The CT dose metric in use has been based on the CTDI , i.e. measurement of dose in
PHANTOMs and limited integration of scattered radiation, and it is used in many countries’
legislation to define "dose reference values" (also called "diagnostic reference levels") for CT
examinations. Many people use these indices, CTDI and DLP, to derive estimates for
vol
is also part of CT acceptance and constancy
effective dose via conversion factors. CTDI
testing. The introduction of a new dose index would change all CT SCANNERS’ CTDI values.
Therefore the intention is to stay with the CTDI , i.e. the integration of primary radiation and
scatter over 100 mm, but adapt the way of measuring and reporting the dose index to
incorporate large collimations and to rate all collimations the same way, i.e. to reflect
approximately the same percentage of CTDI for all collimations.
∞
As defined in the amendment, CTDI is to be measured only for collimations up to 40 mm
with the current equipment, i.e. the PMMA PHANTOMs and a 100-mm chamber, or other
suitable methods that use a RADIATION DETECTOR. For these collimations there is no significant
change of the ratio CTDI / CTDI according to published data. For larger collimations at
100 ∞
the same CT CONDITIONS OF OPERATION, the z-efficiency may be different and must be
evaluated in the dose measurement. This can be accomplished by the measurement of dose
and the CTDI have been refined. Both
‘free air’. Based on these considerations CTDI
100 free air
types of measurement are combined now to determine the CTDI values for larger collimations
and they are explained in detail in informative Annexes CC and DD.
Some additional requirements and refinements related to dose have been added: CTDI and
vol
DLP are defined for a new type of scan mode (‘shuttle mode’). In body CT EXAMINATION it is
clarified that the CTDI and DLP always be reported for the 32-cm diameter PHANTOM. In the
vol
SCANNERS support user-configurable DOSE NOTIFICATION
amendment it is now required that CT
VALUES and DOSE ALERT VALUES.
A new subject area in this Amendment 1 covers requirements for CT SCANNERS providing
images for radiotherapy treatment planning. With this amendment begins the implementation
of this important CT application into the CT safety standard with a set of requirements that is
considered to be safety relevant. It mainly covers scanner hardware adjustments, accuracy of
CT image data, and the conversion of HU to electron and mass density.
– 4 – 60601-2-44 Amend.1 © IEC:2012
201.1.1 Scope
Add the following new sentence:
The scope of this International Standard excludes RADIOTHERAPY SIMULATORS and systems
where the image is created by a source other than an X-RAY TUBE.
201.1.3 Collateral standards
Replace the existing text of this subclause with the following:
Addition:
This particular standard refers to those applicable collateral standards that are listed in
Clause 2 of the general standard and Clause 201.2 of this particular standard.
IEC 60601-1-2 and IEC 60601-1-3 apply as modified in Clauses 202 and 203. IEC 60601-1-8,
1) 2) 3)
IEC 60601-1-9, IEC 60601-1-10 , IEC 60601-1-11 and IEC 60601-1-12 do not apply. All
other published collateral standards in the IEC 60601-1 series apply as published.
For collateral standards published after this particular standard, MANUFACTURERS need to
determine the applicability in accordance with the RISK MANAGEMENT PROCESS.
201.2 Normative references
Add, under "Replacement", the following new reference:
IEC 60601-1-2:2007, Medical electrical equipment – Part 1-2: General requirements for basic
safety and essential performance – Collateral standard: Electromagnetic compatibility –
Requirements and tests
Add, under "Addition", the following new reference:
IEC 60336 Medical electric equipment – X-Ray Tube assemblies for medical diagnosis –
Characteristics of focal spots
201.3 Terms and definitions
201.3.202
CT CONDITIONS OF OPERATION
Add a note 3 to this definition:
NOTE 3 CT CONDITIONS OF OPERATION include parameters that are derived by the system from the user-selectable
parameters.
___________
1)
IEC 60601-1-10, Medical electrical equipment – Part 1-10: General requirements for basic safety and essential
performance – Collateral Standard: Requirements for the development of physiologic closed-loop controllers
2)
IEC 60601-1-11, Medical electrical equipment – Part 1-11: General requirements for basic safety and essential
performance – Collateral Standard: Requirements for medical electrical equipment and medical electrical
systems used in the home healthcare environment
3)
IEC 60601-1-12, Medical electrical equipment – Part 1-12: General requirements for basic safety and essential
performance – Collateral Standard: Requirements for medical electrical equipment and medical electrical
systems intended to be used in the emergency medical services environment
60601-2-44 Amend.1 © IEC:2012 – 5 –
201.3.203
COMPUTED TOMOGRAPHY DOSE INDEX 100
CTDI
Replace the existing text of the definition by the following:
integral of the DOSE PROFILE representative of a single axial scan along a line perpendicular to
the TOMOGRAPHIC PLANE divided by N x T according to the following:
for N × T less than or equal to 40 mm
+50 mm
D (z)
= dz
CTDI
∫
N × T
−50 mm
for N × T greater than 40 mm (all CT CONDITIONS OF OPERATION except collimation are kept the
same for these measurements)
+50 mm
CTDI
D (z)
Ref free air, N×T
= dz ×
CTDI100
∫
(N ×T) CTDI
Ref free air, Ref
−50 mm
where
D(z) is the DOSE PROFILE representative of a single axial scan along a line z
perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as
ABSORBED DOSE in air and is evaluated within a polymethylmethacrylate
PHANTOM (see 203.108);
(PMMA) dosimetry
(N × T) is a specific N × T of 20 mm or the largest N × T available not greater than
Ref
20 mm;
D (z) is the DOSE PROFILE representative of a single axial scan along a line z
Ref
perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as
ABSORBED DOSE in air and is evaluated within a polymethylmethacrylate
(PMMA) dosimetry PHANTOM (see 203.108) for (N × T) ;
Ref
CTDI is the CTDI (201.3.215) for a specific value of N × T;
free air, N × T free air
CTDI is the CTDI (201.3.215) for (N × T) ;
free air, Ref free air Ref
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of
the X-ray source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS.
NOTE 1 The dose is reported as ABSORBED DOSE to air, but for practical purposes the evaluation of ABSORBED
DOSE to air within a PMMA dosimetry PHANTOM is well approximated by measurement of the AIR KERMA.
NOTE 2 This definition assumes that the DOSE PROFILE is centred on z = 0.
NOTE 3 A single axial scan is typically a 360° rotation of the X-ray source.
NOTE 4 When the TOMOGRAPHIC SECTIONS overlap, e.g. in CT SCANNERS with a “z-flying FOCAL SPOT”, the
denominator of the integral needs to be replaced by the total nominal width along z of overlapping tomographic
sections. For example, if the percentage of overlap is 50%, then the denominator would be replaced by 0,5 × N × T.
NOTE 5 Typically the z-axis is the axis of rotation.
NOTE 6 The CTDI is designed to include most of the scattered radiation.
NOTE 7 See Annex CC for explanation.
201.3.204
CT PITCH FACTOR
Replace, in Note 3, the text “or N × T are” by the word “is”.
– 6 – 60601-2-44 Amend.1 © IEC:2012
201.3.212
VOLUME CTDI
w
CTDI
vol
a) for axial scanning
Replace Notes 1 and 2 by the following:
NOTE 1 For the selected CT CONDITIONS OF OPERATION, but irrespective of any scanning length that may be used
clinically, the VOLUME CTDI (CTDI ) is an index of dose based on a convention of 100 mm range of integration
w vol
along the z-axis. For axial scanning, CTDI corresponds to the average dose that would accrue in the PHANTOM
vol
central section of volume equal to the cross sectional area × ∆d.
NOTE 2 For axial scanning with a total table travel much less than N × T, CTDI as defined overestimates the
vol
average dose that would accrue in the PHANTOM central section of volume equal to the cross sectional area ×Δd.
b) for helical scanning
In Note 1 replace the text “or N × T are” by the text “is”.
Replace Notes 2 and 3 by the following:
NOTE 2 For the selected CT CONDITIONS OF OPERATION, but irrespective of any scanning length that may be used
clinically, the VOLUME CTDI (CTDI ) is an index of dose based on a convention of 100 mm range of integration
w vol
along the z-axis. For helical scanning, CTDI corresponds to the average dose that would accrue in the centre of
vol
a 100 mm scan length.
NOTE 3 For helical scanning, when the product of a small number of rotations times the table travel per rotation
is much less than N × T, CTDI as defined overestimates the average dose that would accrue in the centre of a
vol
100-mm scan length.
Add the following new item:
d) for axial scanning without gaps and helical scanning, both involving back-and-forth
PATIENT SUPPORT movement between two positions (shuttle mode)
N ×T
CTDI = n CTDI
vol w
(N ×T ) + R
where
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
n is equal to the total number of rotations for the entire scan series;
R is the distance between the two positions;
CTDI is the WEIGHTED CTDI .
W 100
NOTE 1 Seen Figure 201.102.
NOTE 2 CTDI is evaluated as the time weighed CTDI reflecting the varying CT CONDITIONS OF OPERATION.
w w
60601-2-44 Amend.1 © IEC:2012 – 7 –
Z
F F
R
I I
N × T
(N × T) + R
IEC 1615/12
F FOCAL SPOT
I ISOCENTRE
Z z-direction
Figure 201.102 – Illustration of N × T,R and (N × T) + R
201.3.214
DOSE-LENGTH PRODUCT
DLP
b) For helical scanning
Replace the existing text:
L is the table travel during the entire LOADING.
by the following new text:
L is the table travel during the entire LOADING, adjusted for dynamic collimation modes if
applicable.
Add the following new note:
NOTE 3 A way for obtaining L could be to use the FWHM along a line perpendicular to the TOMOGRAPHIC PLANE at
isocenter of the free-in-air DOSE PROFILE for the entire scan. In the absence of dynamic collimation this is
approximately equivalent to table travel during the entire LOADING.
Add the following new item:
d) for axial scanning without gaps and helical scanning, both involving back-and-forth
PATIENT SUPPORT movement between two positions (shuttle mode)
DLP = CTDI × ((N ×T) + R)
vol
where
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
R is the distance between the two positions.
201.3.215
COMPUTED TOMOGRAPHY DOSE INDEX FREE-IN-AIR
CTDI
FREE AIR
Replace the existing symbol by the following:
CTDI
free air
– 8 – 60601-2-44 Amend.1 © IEC:2012
Replace the existing text of the definition by the following:
integral of the DOSE PROFILE representative of a single axial scan along a line through the
ISOCENTRE and perpendicular to the TOMOGRAPHIC PLANE divided by N × T according to the
following
+L/2
D (z)
= dz
CTDIfree air
∫
N × T
−L/2
where
D(z) is the DOSE PROFILE representative of a single axial scan along a line z through
ISOCENTRE and perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as
ABSORBED DOSE in air and is evaluated free-in-air in the absence of a PHANTOM and the
PATIENT SUPPORT;
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
L is at least (N × T) +40 mm, but not less than 100 mm.
NOTE 1 This definition assumes that the DOSE PROFILE is centred on z = 0.
NOTE 2 When the TOMOGRAPHIC SECTIONS overlap, e.g. in CT SCANNERS with a “z-flying FOCAL SPOT”, the
denominator of the integral needs to be replaced by the total nominal width along z of overlapping tomographic
sections. For example, if the percentage of overlap is 50 %, then the denominator would be replaced by
0,5 × N × T.
NOTE 3 Typically a RADIATION DETECTOR of length L or longer is used. Annex DD provides an example for
alternate measurements.
Add the following new terms and definitions:
201.3.216
PROTOCOL ELEMENT
set of the particular CT CONDITIONS OF OPERATION necessary to perform a scan
NOTE 1 The following modes are examples of different types of scan: helical, axial, axial series, scanning without
movement of the patient support and shuttle mode.
NOTE 2 To maintain consistency with their respective user interfaces and documentation, various CT SCANNERS
might use terminology different from “PROTOCOL ELEMENT”, e.g., “scan”, “scan group”, “scan series”, etc., which
actually means “PROTOCOL ELEMENT”
NOTE 3 A PROTOCOL ELEMENT is typically associated with a defined clinical task, clinical context, anatomical
region, and/or age or size group. It corresponds to one sequence of scanning in a CT EXAMINATION.
201.3.217
CT EXAMINATION
group of PROTOCOL ELEMENTS used for the entire COMPUTED TOMOGRAPHY PROCEDURE for a
particular PATIENT
201.3.218
DOSE NOTIFICATION VALUE
value of CTDI , CTDI per second, or DLP used to trigger a notification on the control
vol vol
panel
NOTE A DOSE NOTIFICATION VALUE could represent a level of concern associated with a dose index value that
would exceed a value normally expected for the PROTOCOL ELEMENT (e.g. a diagnostic reference level or similar
value determined by the RESPONSIBLE ORGANIZATION).
60601-2-44 Amend.1 © IEC:2012 – 9 –
201.3.219
DOSE ALERT VALUE
value of CTDI or DLP used to trigger an alert on the control panel
vol
NOTE A DOSE ALERT VALUE could represent a level of concern (e.g. avoidance of deterministic effects) higher than
that of a DOSE NOTIFICATION VALUE, and it would therefore warrant more stringent review and consideration before
proceeding.”
201.4 General requirements
201.4.3 ESSENTIAL PERFORMANCE
Replace the existing text of this subclause with the following:
Addition:
For CT SCANNERS for which the INTENDED USE includes COMPUTED TOMOGRAPHY as the
principal means of guidance in invasive procedures (e.g., involving the introduction of a
device, such as a needle or a catheter into the body of the PATIENT), any ESSENTIAL
aspects related to such use shall be identified in the ACCOMPANYING DOCUMENTS
PERFORMANCE
and in the RISK MANAGEMENT FILE.
NOTE An example of what would not be considered ESSENTIAL PERFORMANCE is the extraction of needles where
images are not required for guidance.
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS and the RISK
MANAGEMENT FILE.
201.7.9.101 Reference to ACCOMPANYING DOCUMENTS
Replace the following line:
– LIGHT FIELD 203.115
by the following new line:
– Light marker 203.115 c)
Add the following new lines:
– ESSENTIAL PERFORMANCE 201.4.3
– Alignment of the top of the PATIENT SUPPORT 201.101.2
– Top of the PATIENT SUPPORT 201.101.3
– Table sag (stiffness of the PATIENT SUPPORT) 201.101.4
– Integral light markers for PATIENT marking 201.101.5
– Typical scan mode to provide images for RTP 201.101.6
– HU-value conversion 201.101.7
– Geometric accuracy of image data 201.101.8
– Information in the ACCOMPANYING DOCUMENTS 203.10.2
– Display and recording of CTDI and DLP 203.112
vol
201.8.8.3 Dielectric strength
Replace the existing third paragraph with the following:
– 10 – 60601-2-44 Amend.1 © IEC:2012
If the HIGH-VOLTAGE GENERATOR can only be tested with the X-RAY TUBE connected, the test
voltage may be lower but shall not be less than 1,1 times the NOMINAL X-RAY TUBE VOLTAGE of
the HIGH-VOLTAGE GENERATOR or X-RAY TUBE ASSEMBLY ( whichever is lower).
NOTE 101 For the NOMINAL X-RAY TUBE VOLTAGE of the HIGH-VOLTAGE GENERATOR, see also subclause 201.8.4.101,
Limitation of high voltage to the NOMINAL X-RAY TUBE VOLTAGE.
201.9.2.4.101.3 Linear movements of the PATIENT SUPPORT and gantry
In the last sentence of the first paragraph replace "25 mm after actuation" with "50 mm after
actuation".
Add the following two new paragraphs after the existing first paragraph:
If a scan mode is selected in which the PATIENT SUPPORT cannot stop within 25 mm after
actuation of the emergency stop, before the scan is initiated the CT SCANNER shall display an
alert on the CONTROL PANEL regarding this situation and instruct the OPERATOR to ensure the
PATIENT area of travel is free from obstruction.
The ACCOMPANYING DOCUMENTS shall identify the scan modes that cannot meet the 25 mm
emergency stop distance.
Replace the existing compliance statement by:
Compliance is checked by functional test and inspection of the ACCOMPANYING DOCUMENTS.
201.12.1.102 Accuracy of recorded CT EXAMINATION data
Replace existing item a)by the following:
a) When a RADIOGRAM for preview (as described in 203.115 of this particular standard) is
provided, the position of the TOMOGRAPHIC SECTIONS shall be clearly indicated on the
RADIOGRAM.
The indication of the position of the TOMOGRAPHIC SECTIONS shall be accurate within
± 2 mm.
Add the following additional clauses:
201.101 Requirements for CT SCANNERS providing images for RADIOTHERAPY
TREATMENT PLANNING (RTP)
201.101.1 General
Clause 201.101 applies only to CT SCANNERS whose INTENDED USE includes providing image
data for RADIOTHERAPY TREATMENT PLANNING (RTP).
Requirements related to the CT SCANNER (gantry, PATIENT SUPPORT, light markers) and
conversion of Hounsfield Units to electron and mass density are addressed.
201.101.2 Alignment of the top of the PATIENT SUPPORT
201.101.2.1 General
The ACCOMPANYING DOCUMENTS shall describe the procedures for aligning the top of the
PATIENT SUPPORT with respect to the TOMOGRAPHIC PLANE such that the long axis of the top of
the PATIENT SUPPORT is aligned vertically and horizontally over the maximum scan range along
the z direction.
60601-2-44 Amend.1 © IEC:2012 – 11 –
Compliance of the alignment requirements in subclauses 201.101.2.2 and 201.101.2.3 is
checked by inspection of the ACCOMPANYING DOCUMENTS.
201.101.2.2 Alignment of the PATIENT SUPPORT in the vertical plane (tilt)
The alignment procedure shall require the accuracy of the alignment to be ±0,5º or less with
respect to the horizontal plane (Figure 201.103).
The alignment procedure shall require this measurement to be taken on the retracted top of
the PATIENT SUPPORT, without load, after installation.
Y
Z′
t
Z
1 2
IEC 1616/12
Z Z-axis
Z’ Axis of the top of the PATIENT SUPPORT
t Tilt angle
1 Gantry
2 PATIENT SUPPORT
Figure 201.103 – Vertical alignment of the PATIENT SUPPORT
201.101.2.3 Alignment of the PATIENT SUPPORT in the horizontal plane
a) The alignment procedure shall require the axis of the horizontal movement of the top of
the PATIENT SUPPORT to be perpendicular to the x-axis of the TOMOGRAPHIC PLANE within
± 1º.
b) The alignment procedure shall require the centerline of the top of the PATIENT SUPPORT to
be marked at the front end (M1) and at a distance of 1 m from the front end (M2). The
difference between the centerline and the z-axis indicated by the sagittal light marker shall
be measured at the position of the scan plane for both M1 and M2. Neither d1 nor d2 shall
exceed 2 mm (see Figure 201.104). If the sagittal light marker does not extend to the scan
plane, the measurement shall be taken at the external light marker position.
– 12 – 60601-2-44 Amend.1 © IEC:2012
X
M1
d1
Z
Z′
M2
1 IEC 1617/12
Figure 201.104a
60601-2-44 Amend.1 © IEC:2012 – 13 –
X
M1
Z
d2
Z′
M2
IEC 1618/12
Figure 201.104b
Z Z-axis
Z’ Axis of the top of the PATIENT SUPPORT
1 Gantry
M1, M2 Markings on the top of the PATIENT SUPPORT
d1, d2 distance of Markings from Z-axis
Figure 201.104 – Z-axis alignment of the
PATIENT SUPPORT in the horizontal plane
201.101.3 Top of the PATIENT SUPPORT
The surface of the PATIENT SUPPORT shall be flat or an ACCESSORY to make it flat shall be
specified in the ACCOMPANYING DOCUMENTS and shall be made available.
The PATIENT SUPPORT should allow use of the positioning aids of the therapy system.
201.101.4 Table sag (stiffness of the PATIENT SUPPORT)
Table sag shall be specified for ranges of 40 cm (typical scan length plus shift to reach the
scan plane).
NOTE Corrections for table sag might be needed in the process of RTP.
The sag of the PATIENT SUPPORT in the scan plane shall be evaluated according to the
following test specification:
– 14 – 60601-2-44 Amend.1 © IEC:2012
– Starting at the gantry-side end of the top of the PATIENT SUPPORT, distribute a load of
135 kg evenly over a length of 1,9 m (or maximum length of the top of the PATIENT
SUPPORT whichever is less);
– position the gantry-side end of the top of the PATIENT SUPPORT in the scan plane
(position 1);
– measure the vertical position of the top of the PATIENT SUPPORT in the scan plane
(height 1);
– move the top of the PATIENT SUPPORT into the gantry by 400 mm
(position 2 = position 1 + 400 mm);
– measure the vertical position of the top of the PATIENT SUPPORT in the scan plane
(height 2);
– move the top of the PATIENT SUPPORT into the gantry by another 400 mm
(position 3 = position 2 + 400 mm) and measure the vertical position of the top of the
PATIENT SUPPORT in the scan plane (height 3);
– move the top of the PATIENT SUPPORT into the gantry by another 400 mm
(position 4 = position 3 + 400 mm) and measure the vertical position of the top of the
PATIENT SUPPORT in the scan plane (height 4);
– calculate and record the differences in height (the sag) between each pair of adjacent
positions.
Images may be generated at the described z-positions to measure the height of the top of the
PATIENT SUPPORT (e.g. distance between top of the PATIENT SUPPORT and the ISOCENTRE).
If the mechanical design of the PATIENT SUPPORT can be expected to cause the PATIENT
SUPPORT to sag over the exam time (e.g. in the case of a hydraulic device) the PATIENT
SUPPORT shall be left loaded in the most extended position for 1 h, and the measurement shall
be repeated at this position.
The results of the calculations of the differences in height shall be reported in the
ACCOMPANYING DOCUMENTS.
201.101.5 Integral light markers for PATIENT marking
If light markers are integral to the CT SCANNER, the ACCOMPANYING DOCUMENTS shall confirm
whether or not they are intended for the purpose of PATIENT marking in RTP.
If the integral light markers are intended for the purpose of PATIENT marking in RTP, they shall
have the following accuracy:
The accuracy of the axial light marker shall be ±1 mm at the ISOCENTRE and ±2 mm at a
distance of ± 250 mm in x-direction.
Sagittal and coronal light markers shall extend into the scan plane and shall be accurate
by ± 1 mm with respect to the axis of rotation.
The width of the light markers shall not exceed 1 mm (FWHM) at the ISOCENTRE.
NOTE Other light markers are covered by existing requirements in the CT equipment acceptance-test standard
(IEC 61223-3-5) as well as in IEC 60601-2-44. In IEC 61223-3-5, see 5.2.1.3.1 on the internal patient-positioning
light indicating the scan plane, and also see 5.2.1.3.2 on the external positioning light. In this standard, see
203.115(c).
201.101.6 Typical scan mode to provide images for RTP
The ACCOMPANYING DOCUMENTS shall specify CT CONDITIONS OF OPERATION that are typical for
providing images for RTP. Protocols not suitable for providing images for RTP shall be
identified in the ACCOMPANYING DOCUMENTS.
60601-2-44 Amend.1 © IEC:2012 – 15 –
Results of the tests for NOISE, MEAN CT-NUMBER, and UNIFORMITY, as measured with the
methodology of IEC 61223-3-5, shall be provided in the ACCOMPANYING DOCUMENTS for CT
CONDITIONS OF OPERATION that are typical for RTP.
201.101.7 HU-value conversion
A conversion of measured HU-values to electron and mass density values relative to those of
water using CT CONDITIONS OF OPERATION identified in 201.101.6 shall be provided in the
ACCOMPANYING DOCUMENTS as a representative figure for that scanner model. At a minimum,
conversion factors shall be provided for air, water, one soft-tissue-equivalent material and two
different bone-equivalent materials.
The PHANTOM and the CT CONDITIONS OF OPERATION used to provide this conversion shall be
specified in the ACCOMPANYING DOCUMENTS. The PHANTOM shall be commercially available.
The ACCOMPANYING DOCUMENTS shall state the limitations of the data for the full field-of-view
and specify if there are regions with different levels of accuracy.
201.101.8 Geometric accuracy of image data
201.101.8.1 General
The imaging data shall be geometrically accurate over the full scan field-of-view. The
subclauses of 201.101.8 fulfill this requirement.
The ACCOMPANYING DOCUMENTS shall state the limitations in geometric accuracy for the full
scan field-of-view and specify if there are regions with different levels of accuracy.
The ACCOMPANYING DOCUMENTS shall describe the test specifications to check the alignment
according to subclauses 201.101.8.2, 201.101.8.3 and 201.101.8.4.
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS.
201.101.8.2 Gantry tilt
It shall be possible to set the gantry tilt to zero-position with an accuracy of within ±1 º with
reference to the plane through the x-axis and perpendicular of table top.
The test method is according to IEC 61223-3-5, Annex D.
201.101.8.3 Angular alignment of CT images
Angular alignment of the reconstructed images is essential for accuracy in RTP. Image
alignment shall be checked with an object of known geometry.
• Test specification
Position a PHANTOM with markers aligned to the horizontal or vertical plane in the scan field.
Scan the PHANTOM and check orientation of the markers in the image.
The deviation of the marker from the vertical or horizontal reference shall be less than 3 mm
over a distance of 20 cm.
201.101.8.4 Accuracy of image z-position for helical scans
The accuracy of the actual z-position of the PATIENT SUPPORT and the z-position stated in the
image shall be checked.
– 16 – 60601-2-44 Amend.1 © IEC:2012
• Test specification
A PHANTOM with markers at z-position 0 cm, 15 cm and 30 cm is used. The markers have to
be visible in the CT-image (e.g. metal beads). The PHANTOM is positioned in a way that marker
“0 cm” is in the field of the light marker. The table is set to zero for that position. A helical
scan with a protocol intended for providing images for RTP is executed over a scan range
covering all three markers on the PHANTOM and overlapping images are reconstructed using
the thinnest available TOMOGRAPHIC SECTIONS. For each marker the slice position with the
maximum contrast for the marker shall be identified and recorded.
The deviation of the image positions from their corresponding nominal z-values shall be less
than 1 mm.
202 Electromagnetic compatibility – Requirements and tests
IEC 60601-1-2:2007 applies, except as follows:
Additional subclause:
202.101 Immunity testing of ESSENTIAL PERFORMANCE
The MANUFACTURER may minimize the test requirements of the additional ESSENTIAL
PERFORMANCE listed in subclause 201.4.3 to a practical level through the RISK MANAGEMENT
PROCESS.
When selecting the requirements to be tested, the MANUFACTURER shall take into account the
sensitivity to the EMC environment, probability of EMC condition and severity, probability and
contribution to unacceptable RISK through the RISK MANAGEMENT PROCESS.
The accuracy of the test instruments used to assess the immunity of the CT SCANNER shall not
be affected by the electromagnetic conditions for the test.
The test instrument shall not have an influence on the immunity of the CT SCANNER.
Only non-invasive measurements shall be performed.
The CT SCANNER being tested shall not be modified to perform this immunity test.
Compliance is checked by inspection of the RISK MANAGEMENT FILE.
203 General requirements for RADIATION protection in diagnostic X-ray
equipment
203.6.7.3 NOMINAL FOCAL SPOT value
Replace the existing text of this subclause by:
Amendment:
The requirement "and shall be compatible with each application within the INTENDED USE" shall
not apply.
Replacement of the compliance statement:
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS.
60601-2-44 Amend.1 © IEC:2012 – 17 –
203.10 ATTENUATION of the X-RAY BEAM between the PATIENT and the X-RAY IMAGE
RECEPTOR
Replace the existing text of this subclause by the following:
Clause 10 of the collateral standard applies with the following exception:
203.10.2 Information in the ACCOMPANYING DOCUMENTS
Subclause 10.2 of the collateral standard does not apply.
203.13.1 General
Delete, in the last sentence of the subclause, the phrase "of 500 cm ".
203.102 Visual indication
Replace the entire text of this subclause by the following:
Prior to initiation of the scan series, the user selected CT CONDITIONS OF OPERATION to be
used during a scan series shall be indicated on the CONTROL PANEL from which the READY
STATE can be initiated.
On ME EQUIPMENT having all or some of these CT CONDITIONS OF OPERATION at fixed values,
this requirement may be met by permanent markings.
For scans in which the TUBE CURRENT varies, indication of the expected time weighted average
over the scan series shall be available prior to scan initiation.
Compliance is checked by the appropriate functional tests.
203.107 Safety measures against excessive X-RADIATION
Add the following new items:
g) Means shall be provided to allow users to optionally enter and save a DOSE NOTIFICATION
VALUE in terms of CTDI , CTDI per second, DLP, and/or DLP per second as part of
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each PROTOCOL ELEMENT. When a PROTOCOL ELEMENT is confirmed, the CT SCANNER shall
display a notification on the CONTROL PANEL if any of the estimated dose index values
exceeds the corresponding DOSE NOTIFICATION VALUE. The OPERATOR shall be required to
confirm this notification before continuing. Means shall be provided to allow the OPERATOR
to enter comments regarding the exceedance.
When a scan is performed that exceeds a DOSE NOTIFICATION VALUE, the system shall
record the date and time, a unique identifier for the CT EXAMINATION and the PROTOCOL
ELEMENT, the DOSE NOTIFICATION VALUES which were exceeded at the pre-scan confirmation,
the corresponding dose index values which triggered the notification, and comments, if
provided. This record shall be available to the user.
Means shall be provided to generate a list of all PROTOCOL ELEMENTS with their
corresponding DOSE NOTIFICATION VALUES. If the DOSE NOTIFICATION VALUE is not set for a
particular PROTOCOL ELEMENT, the list shall indicate this status.
h) Means shall be provided to allow users to optionally enter and save at least one DOSE
ALERT VALUE in terms of CTDI and/or a DLP. For each CT EXAMINATION, the system shall
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accumulate values of CTDI at each position on the z-axis and shall accumulate the total
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DLP as the CT EXAMINATION proceeds. The system may set the accumulated CTDI to
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zero when the PATIENT coordinate system shifts, e.g. when the PATIENT changes position
on the PATIENT SUPPORT. When a PROTOCOL ELEMENT is confirmed, the CT SCANNER shall
display an alert on the CONTROL PANEL if the accumulated CTDI or the accumulated DLP,
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– 18 – 60601-2-44 Amend.1 © IEC:2012
plus the corresponding values estimated for the confirmed PROTOCOL ELEMENTS, exceeds
the corresponding DOSE ALERT VALUE. The OPERATOR shall be required to confirm this alert
and to enter OPERATOR's name before continuing. Means shall be provided to allow the
OPERATOR to enter comments regarding the exceedance.
The system shall also provide password-protection capability that prevents proceeding
with the scan unless the correct password is entered. The activation of the password-
protection capability may be configurable.
When a scan is performed that exceeds a DOSE ALERT VALUE, the system shall record the
date and time, the OPERATOR name, a unique identifier for the CT EXAMINATION, the DOSE
ALERT VALUES which were exceeded, the corresponding dose index values which triggered
the alert, and any comments, if provided. This record shall be available to the OPERATOR.
The DOSE ALERT VALUE for CTDI shall not be allowed to exceed 2 Gy.
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Means shall be provided to generate a list of all DOSE ALERT VALUES. If any of the DOSE
ALERT VALUES have not been set, the list shall indicate this status.
203.108 Dosimetry PHANTOM
At the end of the first sentence in the first paragraph replace the words " for head techniques
and 320 mm for body techniques" by " for all head PROTOCOL ELEMENTS and 320 mm for all
body PROTOCOL ELEMENTS".
203.109 Dose statements
203.109.2 CTDI
free air
In the second sentence of the first paragraph delete the text "with a 100 mm long ionization
chamber aligned".
Add, after Note 2 the following new note:
NOTE 3 An alternative method to measure CTDI (CTDI or CTDI ) is based on measurement of the DOSE
100 free air
PROFILE and integration of the profile over the desired range. The dose profile can be measured with a RADIATION
DETECTOR that fulfils IEC 61674, e.g. with a small dosimeter.
203.110 DOSE PROFILE statement
Replace the final sentence of the first paragraph by the following:
For CT SCANNERS with a single detector row along the z-axis, the DOSE PROFILE shall be
presented on the same graph and to the same scale as the corresponding SENSITIVITY PROFILE
required by 203.111. For CT SCANNERS with multiple detector rows along the z-axis, two
vertical line segments separated by the width N × T shall be presented on the same graph
centered within the DOSE PROFILE.
203.111 SENSITIVITY PROFILE statement
Replace the existing text of this subclause by the following:
A graphical representation of the associated SENSITIVITY PROFILE shall be given in the
ACCOMPANYING DOCUMENTS as follows:
a) One SENSITIVITY PROFILE for each available axial NOMINAL TOMOGRAPHIC SECTION THICKNESS
shall be plotted. If there are more than three NOMINAL TOMOGRAPHIC SECTION THICKNESSES,
plot the SENSITIVITY PROFILE for at least the minimum, the maximum and one midrange
value.
b) For CT SCANNERS with a single detector row along the z-axis, the SENSITIVITY PROFILE
associated with the configuration T shall be presented on the same graph, placed about
60601-2-44 Amend.1 © IEC:2012 – 19 –
the same central location, to the same scale as that of the corresponding DOSE PROFILE
required by 203.110, for the head-dosimetry PHANTOM and for the body-dosimetry
PHANTOM,
Compliance is checked by inspection of the ACCOMPANYING DOCUMENTS.
203.112 Display and recording of CTDI and DLP
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Replace the entire existing text of this subclause by the following:
.
The values for CTDI expressed in units of mGy and DLP expressed in units of mGy cm,
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both quantities reflecting the PROTOCOL ELEMENT selected, shall be displayed on the CONTROL
PANEL prior to initiation of a scanning sequence. Additionally, the PHANTOM diameter on which
CTDI values are based shall be displayed.
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The ACCOMPANYING DOCUMENTS shall contain the conversion from the CTDI based on the 32
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cm phantom to the CTDI based on the 16 cm phantom. This conversion shall be provided
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for all relevant combinations of CT CONDITIONS OF OPERATION. The ACCOMPANYING DOCUMENTS
shall contain guidance on how to specify whether a PROTOCOL ELEMENT is a head or body
PROTOCOL ELEMENT.
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