IEC 61391-1:2006

Ultrasonics - Pulse-echo scanners - Part 1: Techniques for calibrating spatial measurement systems and measurement of system point-spread function response

Describes methods of calibrating the spatial measurement facilities and point-spread function of ultrasonic imaging equipment in the ultrasonic frequency range 0,5 MHz to 15 MHz. This standard is relevant for ultrasonic scanners based on the pulse echo principle of the types listed below: - mechanical sector scanners; - electronic phased-array sector scanners; - electronic linear-array scanners; - electronic curved-array sector scanners; - water bath scanners based on any of the above four scanning mechanisms; - 3D-volume reconstruction systems.

Ultrasons - Scanners à impulsion et écho - Partie 1: Techniques pour l'étalonnage des systèmes de mesure spatiaux et des mesures de la réponse de la fonction de dispersion ponctuelle du système

Décrit des méthodes d'étalonnage des moyens de mesure spatiaux et de la fonction de dispersion ponctuelle d'équipements d'imagerie à ultrasons, dans la gamme des fréquences ultrasoniques s'étendant de 0,5 MHz à 15 MHz. La norme s'applique aux scanners ultrasoniques basés sur le principe d'impulsion et écho des types suivants: - scanners sectoriels à balayage mécanique; - scanners sectoriels électroniques à réseau de phase; - scanners électroniques à réseau linéaire; - scanners sectoriels électroniques à réseau courbe; - scanners à bain d'eau, basé sur l'un des quatre mécanismes de balayage précédents; - systèmes de reconstruction de volume en 3D.

General Information

• Status: Published
• Publication Date: 10-Jul-2006
• ICS: 17.140.50 - Electroacoustics
• Technical Committee: TC 87 - Ultrasonics
• Drafting Committee: WG 9 - TC 87/WG 9
• Current Stage: PPUB - Publication issued
• Start Date: 15-Aug-2006
• Completion Date: 11-Jul-2006

Relations

• Amended By: IEC 61391-1:2006/AMD1:2017 - Amendment 1 - Ultrasonics - Pulse-echo scanners - Part 1: Techniques for calibrating spatial measurement systems and measurement of point-spread function response
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61391-1 ®
Edition 1.1 2017-07
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
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Ultrasonics – Pulse-echo scanners –
Part 1: Techniques for calibrating spatial measurement systems and
measurement of system point-spread function response

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IEC 61391-1 ®
Edition 1.1 2017-07
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Ultrasonics – Pulse-echo scanners –

Part 1: Techniques for calibrating spatial measurement systems and

measurement of system point-spread function response

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.140.50 ISBN 978-2-8322-4589-7

IEC 61391-1 ®
Edition 1.1 2017-07
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Ultrasonics – Pulse-echo scanners –
Part 1: Techniques for calibrating spatial measurement systems and
measurement of system point-spread function response

– 2 – IEC 61391-1:2006+AMD1:2017 CSV
 IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
4 Symbols . 15
5 General conditions . 16
6 Techniques for calibrating 2D-measurement systems . 17
6.1 Test methods . 17
6.2 Instruments . 17
6.3 Test settings . 18
6.4 Test parameters . 19
7 Methods for calibrating 3D-measurement systems . 21
7.1 General . 21
7.2 Types of 3D-reconstruction methods . 21
7.3 Test parameters associated with reconstruction problems . 22
7.4 Test methods for measurement of 3D-reconstruction accuracy . 23
8 Measurement of point-spread and line-spread functions (high-contrast spot size) . 27
8.1 General . 27
8.2 Test methods . 28
8.3 Instruments . 28
8.4 Test settings . 29
8.5 Test parameters . 31
Annex A (normative) Test objects – Calibration of 2D-spatial measurement systems . 36
Annex B (normative) Test objects – Measurement and calibration of 3D-image
reconstruction accuracy . 39
Annex C (normative) Test objects – Measurement of point-spread function response . 43
Annex D (informative) Quality parameters derived by PSF-mapping analysis . 48
Bibliography . 64

Figure A.1 – Concentric circular arrays of nylon filaments . 37
Figure A.2 – Regular 2D-array of nylon filaments . 38
Figure B.1 – Tissue mimicking ovoid target phantom . 40
Figure B.2 – Composite of two cross-sectional views of test object shown in Figure B.1 . 40
Figure B.3 – Projection view from top of test object shown in Figure B.1 . 41
Figure B.4 – Projection view from end window of test object shown in Figure B.1 . 42
Figure C.1 – Filament test object for measuring the LSF . 44
Figure C.2 – Axial resolution test object . 45
Figure C.3 – Movable single filament in water . 46
Figure C.5 – Slice thickness measurement and calculation . 47
Figure D.1 – Principal schematic of the PSF-analyser function . 51
Figure D.2 – Principle of elimination of internal multi-reflections in the spherical target
using filtration in time domain . 54

 IEC 2017
Figure D.4 – The derivation of FWHM-value from the lateral-amplitude profile of PSF
received-echo signal (a (x ,z ) = 221) with reflector positioned on axis of the
r,max i k
ultrasound beam in point (x ,z ) of the measuring grid . 57
i k
Figure D.5 – The FWHM-derivation from the elevational (transversal) profile of MER in
one point of the measuring grid . 58
Figure D.6 – The derivation of the reflected-signal axial-profile from the ROI . 59
Figure D.7 – The enumeration of the W parameter from the axial-profile line:
H,HM
a (x,z) = 243 . 59
r,max
Figure D.8 – The distribution of FWHM over a scan area of width 20 mm to depth 80
mm, made with a monofocal scan using a linear 5 MHz transducer . 60
Figure D.9 – The distribution of FWHM over a scan area of width 20 mm to depth 80
mm, made with the same system as for Figure D.7 but using three focal points (F1, F2
and F3) for the scan . 60
Figure D.10 – Plot of the distribution of MER-intensity over the scanning area 30 mm
wide and 40 mm deep . 61
Figure D.3 – A pixel maximum level and PSF-trace estimation in ROI stored digital data . 56
Figure D.11 – The elevational profile recorded from a (x ,y,z ) values for a spherical
r,max i k
target passing perpendicularly to the scanning plane in one point (x ,z ) of the
i k
measuring grid . 62

Table 1 – Expected values for the two ellipsoidal objects in Figure B.3 . 27
Table 2 – Suggested table of reported values . 27

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 IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ULTRASONICS – PULSE-ECHO SCANNERS –
Part 1: Techniques for calibrating spatial measurement systems
and measurement of system point-spread function response
FOREWORD
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This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 61391-1 edition 1.1 contains the first edition (2006-07) [documents 87/336/FDIS and 87/343/
RVD] and its amendment 1 (2017-07) [documents 87/650/FDIS and 87/653/RVD].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text.
A separate Final version with all changes accepted is available in this publication.

 IEC 2017
International Standard IEC 61391-1 has been prepared by IEC technical committee 87:
Ultrasonics.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
Terms in bold in the text are defined in clause 3.
This standard is intended to be published in two or more parts:
– Part 1 deals with techniques for calibrating spatial measurement systems and
measurement of system point-spread function response;
– Part 2 will deal with measurement of system sensitivity, dynamic range, and low-contrast
resolution.
The committee has decided that the contents of the base publication and its amendment 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.
A bilingual version of this publication may be issued at a later date.

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.

– 6 – IEC 61391-1:2006+AMD1:2017 CSV
 IEC 2017
INTRODUCTION
An ultrasonic pulse-echo scanner produces images of tissue in an ultrasonic scan plane by
sweeping a narrow pulsed beam of ultrasound through the section of interest and detecting
the echoes generated at tissue boundaries. A variety of ultrasonic transducer types are
employed to operate in a transmit/receive mode for the ultrasonic signals. Ultrasonic scanners
are widely used in medical practice to produce images of many soft-tissue organs throughout
the human body.
This standard describes test procedures that should be widely acceptable and valid for a wide
range of types of equipment. Manufacturers should use the standard to prepare their
specifications; the users should employ the standard to check specifications. The
measurements can be carried out without interfering with the normal working conditions of the
machine. Typical test objects are described in the annexes. The structures of the test objects
have not been specified in detail, rather suitable types of overall and internal structures are
described. The specific structure of a test object should be reported with the results obtained
using it. Similar commercial versions of these test objects are available.
The performance parameters specified and the corresponding methods of measurement have
been chosen to provide a basis for comparison with the manufacturer's specification and
between similar types of apparatus of different makes, intended for the same kind of diagnostic
application. The manufacturer's specification should allow comparison with the results obtained
from the tests in this standard. Furthermore, it is intended that the sets of results and values
obtained from the use of the recommended methods will provide useful criteria for predicting
the performance of equipment in appropriate diagnostic applications. This standard
concentrates on measurements of images by digital techniques. Methods suitable for
inspection by eye are covered here as well. Discussion of other visual techniques can be found
1)
in IEC 61390 [1] .
Where a diagnostic system accommodates more than one option in respect of a particular
system component, for example the ultrasonic transducer, it is intended that each option be
regarded as a separate system. However, it is considered that the performance of a machine is
adequately specified, if measurements are undertaken for the most significant combinations of
machine control settings and accessories. Further evaluation of equipment is obviously
possible but this should be considered as a special case rather than a routine requirement.
___________
)
Figures in square brackets refer to the Bibliography.

 IEC 2017
ULTRASONICS – PULSE-ECHO SCANNERS –

Part 1: Techniques for calibrating spatial measurement systems
and measurement of system point-spread function response

1 Scope
This International Standard describes methods of calibrating the spatial measurement facilities
and point-spread function of ultrasonic imaging equipment in the ultrasonic frequency range
0,5 MHz to 15 MHz. This standard is relevant for ultrasonic scanners based on the pulse-echo
principle of the types listed below:
− mechanical sector scanners;
− electronic phased-array sector scanners;
− electronic linear-array scanners;
− electronic curved-array sector scanners;
− water-bath scanners based on any of the above four scanning mechanisms;
− 3D-volume reconstruction systems.
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.
IEC 61102:1991, Measurement and characterisation of ultrasonic fields using hydrophones in
the frequency range 0,5 MHz to 15 MHz
IEC 60050-801:1994, International Electrotechnical Vocabulary – Chapter 801: Acoustics and
electroacoustics
IEC 60050-802:2011, International Electrotechnical Vocabulary – Part 802: Ultrasonics
IEC 61685:2001, Ultrasonics – Flow measurement systems – Flow test object
IEC 62127-1:2007, Ultrasonics – Hydrophones – Part 1: Measurement and characterization of
medical ultrasonic fields up to 40 MHz
3 Terms and definitions
For the purposes of this document, the following terms and definitions given in IEC 60050-
801:1994, IEC 60050-802:2011, IEC 62127-1:2007 and the following apply. See also related
International Standards, Technical Specifications and Technical Reports for definitions and
explanations [1] [2] [3] [4] [34] [35] [36] [37] [38] [39]. [1-5]
3.1
A-scan
class of data acquisition geometry in one dimension, in which echo strength information is
acquired from points lying along a single beam axis and displayed as amplitude versus time of
flight or distance
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 IEC 2017
3.2
acoustic coupling agent (also, coupling agent)
a material, usually a gel or other fluid, that is used to ensure acoustic contact between the
transducer and the patient’s skin, or between the transducer and the surface of a sealed test
object
3.3
acoustic working frequency
arithmetic mean of the frequencies f and f at which the amplitude of the acoustic pressure
1 2
spectrum is 3 dB below the peak amplitude
(See 3.4.2 of IEC 61102)
3.4
automatic time-gain compensation
ATGC
automatic working time gain control based on the observed decrease in echo amplitudes due to
the attenuation in ultrasonic pulse amplitude with depth
3.5
axial resolution
minimum separation along the beam axis of two equally scattering volumes or targets at a
specified depth for which two distinct echo signals can be displayed
3.6
backscatter coefficient
mean acoustic power scattered in the 180º direction by a specified object with respect to the
direction of the incident beam, per unit solid angle per unit volume, divided by the incident
beam intensity. For a volume filled with many scatterers, the scatterers are considered to be
randomly distributed. The mean power is obtained from different spatial realisations of the
scattering volume
NOTE Backscatter coefficient is commonly referred to as the differential scattering cross-section per unit volume
in the 180° direction
3.7
backscatter contrast (normalized)
difference between the backscatter coefficients from two defined regions divided by the
square root of the product of the two backscatter coefficients
3.8
beam axis
the longitudinal axis of the pulse-echo response pattern of a given B-mode scan line, a
pulse-echo equivalent to the transmitted beam axis of IEC 61828 [2]
3.9
B-scan
class of data acquisition geometry in which echo information is acquired from points lying in an
ultrasonic scan plane containing interrogating ultrasonic beams. See B-mode below.
NOTE B-scan is a colloquial term for B-mode scan or image. (See 3.10)
3.10
Brightness-modulated display
B-mode
method of presentation of B-scan information in which a particular section through an imaged
object is represented in a conformal way by the scan plane of the display and echo amplitude is
represented by local brightness or optical density of the display
[IEC 60854: definition 3.18, modified]

 IEC 2017
3.11
displayed dynamic range
ratio, expressed in decibels, of the amplitude of the maximum echo that does not saturate the
display to the minimum echo that can be distinguished in the display under the scanner test
settings
3.12
elevational resolution
minimum separation perpendicular to the ultrasonic scan plane of two equally scattering
targets at a specified depth for which two distinct echo signals can be displayed. Often used
here informally for slice thickness for purposes of 3D-scanning
3.13
field-of-view
area in the ultrasonic scan plane which is insonated by the ultrasound beam during the
acquisition of echo data to produce one image frame
3.14
frame rate
number of sweeps comprising the full-frame refresh rate that the ultrasonic beam makes per
second through the field-of-view
3.15
gain
ratio of the output to the input of a system, generally an amplifying system, usually expressed
in decibels
3.16
grey scale
range of values of image brightness, being either continuous between two extreme values or, if
discontinuous, including at least three discrete values
[IEC 60854: definition 3.14]
3.17
lateral resolution
minimum separation of two line targets at a specified depth in a test object made of
tissue-mimicking material for which two distinct echo signals can be displayed. The line
targets should be perpendicular to the scanned plane; the separation between the targets
should be perpendicular to the beam-alignment axis
3.18
line-spread function
LSF
characteristic response in three dimensions of an imaging system to a high-contrast line target
3.19
line target
cylindrical reflector whose diameter is so small that the reflector cannot be distinguished by the
imaging system from a cylindrical reflector with diameter an order of magnitude smaller, except
by signal amplitude. The backscatter from a standard line target should be a simple function
of frequency over the range of frequencies studied

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 IEC 2017
3.20
M-mode
time-motion mode
method of presentation of M-scan information in which the motion of structures along a fixed
beam axis is depicted by presenting their positions on a line which moves across a display to
show the variation with time of the echo
3.21
M-scan
time-motion scan
class of acquisition geometry in which echo information from moving structures is acquired
from points lying along a single beam axis. The echo strength information is presented using
an M-mode display
3.22
nominal frequency (of a transducer)
intended acoustic working frequency of a transducer as quoted by the designer or
manufacturer
[adapted from definition 3.7 of IEC 60854]
3.23
pixel
picture element
smallest spatial unit or cell size of a digitized 2-dimensional array representation of an image.
Each pixel has an address (x-and y-coordinates corresponding to its position in the array) and
a specific brightness level
NOTE Pixel is a contraction of ‘picture element’.
3.24
point target
reflector whose scattering surface dimensions are so small that it cannot be distinguished
(except by signal amplitude) by the imaging system from a similar target whose scattering
surface is an order of magnitude smaller. The backscatter cross section of a standard point
target should be a simple function of frequency over the range of frequencies studied.
3.25
point-spread function
PSF
characteristic response in three dimensions of an imaging system to a high-contrast point
target.
NOTE For most ultrasound systems, an individual ultrasound PSF cannot be used as the overall system impulse
response, due to changes in the PSF with depth, with other positions in the region of use and with system focal and
frequency settings. The problem is solved by PSF mapping – see Annex D.
3.26
scan line
one of the component lines which form a B-mode image on an ultrasound monitor. Each line is
the envelope-detected A-scan line in which the echo amplitudes are converted to brightness
values
3.27
scan plane
a plane containing the ultrasonic scan lines
[IEC 61102: definition 3.38, modified]

 IEC 2017
3.28
side lobe
secondary beam, generated by an ultrasonic transducer, that deviates from the direction of
the main beam. Usually, the intensity of the side lobes is significantly less than that of the
central axis beam
NOTE The presence of side lobes may be responsible for introducing artifactual echoes into the ultrasound
image.
3.29
slice thickness
thickness, perpendicular to the ultrasonic scan plane and at a stated depth in the test object,
of that region of the test object from which acoustic information is displayed
3.30
speckle pattern
image pattern or texture, produced by the interference of echoes from the scattering centres in
tissue or tissue-mimicking material
3.31
spot size
the –6 dB width or otherwise specified width of the PSF or LSF
3.32
target
an object to be interrogated by an ultrasound beam
NOTE Examples of targets are:
a) a device specifically designed to be inserted into the ultrasonic field to serve as the object on which the
radiation force is to be measured;
b) a scatterer or ensemble of scatterers giving rise to a signal within the effective ultrasonic beam;
c) a wire or a filament in a test object.
3.33 test object
device containing one or more groups of object configurations embedded in a tissue-
mimicking material or another medium
3.34 test object scanning surface
surface on the tissue-mimicking test object recommended for transducer location during a test
procedure
3.35
time-gain compensation
TGC
change in amplifier gain with time, introduced to compensate for loss in echo amplitude with
increasing depth due to attenuation in tissue
3.36
tissue-mimicking material
material in which the propagation velocity (speed of sound), reflecting, scattering and
attenuating properties are similar to those of soft tissue for ultrasound in the frequency range
0,5 MHz to 15 MHz.
[See 6.4 and Annex D of IEC 61685]
3.37
transmitted ultrasound field
three-dimensional distribution of ultrasound energy emanating from the ultrasonic transducer

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 IEC 2017
3.38
ultrasonic scan line
for automatic scanning systems, the beam-alignment axis either for a particular ultrasonic
transducer element or for a single or multiple excitation of an ultrasonic transducer or of an
ultrasonic transducer element group
[IEC 61157: definition 3.27, modified]
3.39
ultrasonic transducer
device capable of converting electrical energy to mechanical energy within the ultrasonic
frequency range and/or reciprocally capable of converting mechanical energy to electrical
energy
[IEC 61102: definition 3.58]
NOTE For the purposes of this standard, ultrasonic transducer is taken to refer to a complete assembly that
includes the transducer element or elements and mechanical and electrical damping and matching provisions.
3.40
ultrasonic transducer element group
group of elements of an ultrasonic transducer which are excited together in order to produce
a single acoustic pulse
[IEC 61102: definition 3.60]
3.41
ultrasound
acoustic oscillation whose frequency is above the high-frequency limit of audible sound
(conventionally 20 kHz)
[IEV 801 21-04, modified]
3.42
ultrasound beam (pulse-echo response pattern)
region adjacent to the transducer face from which an echo signal from a specified target may
be detected for the test settings of the scanner and with the scanner operating in a
non-scanning mode. This term should be distinguished from the transmitted ultrasound field
3.43
voxel
smallest spatial unit or cell size of a digitized 3-dimensional array representation of an image.
Each voxel has an address (x, y, and z-coordinates) corresponding to its position in the array,
and a specific brightness and/or color value
3.44
working liquid
a mixture of water and other solvent that adjusts the speed of sound to 1 540 m/s
[See also 6.4 and Annex D of IEC 61685:2001]
3.45
accuracy
closeness of agreement between a test result and the accepted reference value
[SOURCE: ISO 5725-1:1994, 3.6]
3.46
axial resolution in a PSF-map
twice the Half-Width-at-Half-Maximum (HWHM) of a function’s trace created from a set of
increasing pixel values, commencing near zero and terminating at the first maximum value

 IEC 2017
(centre of the PSF) and representing the leading edge of the echo signal from a point reflector
located on the main beam axis
Note 1 to entry: The axial resolution in a PSF map differs from the axial resolution specified by 3.5. It is used
for the PSF-mapping only to simplify the data acquisition.
Note 2 to entry: A detailed explanation of the axial resolution in the PSF-map measuring method is in D.6.1.4.
Note 3 to entry: The axial resolution mainly depends on the ultrasound frequency used, not on sonograph
construction.
Note 4 to entry: Axial resolution in a PSF-map is expressed in metres.
3.47
brightness
luminance as perceived by the human visual system
[SOURCE: IEC 62563-1:2009, 3.1.2]
3.48
contrast
C
ratio of the difference of the luminance of two image areas, L − L , divided by the average of
1 2
the two luminance values:
C = 2 (L − L )/(L + L )
1 2 1 2
[SOURCE: IEC 62563-1:2009, 3.1.6]
3.49
dynamic imaging
real-time imaging
imaging with a frame rate that is high enough to observe moving structures in apparently
continuous motion
3.50
elevational resolution in a PSF-map
difference of point-reflector displacements in passing through the scanning plane in an
elevational direction, which result in decreases of MER of −6 dB compared to the MER-value in
the beam centre
Note 1 to entry: The elevational resolution in a PSF-map differs from the elevational resolution specified by
3.12. It is used for the PSF-mapping only to simplify the data acquisition.
Note 2 to entry: Detailed explanation of the method is in D.6.1.3.
Note 3 to entry: Elevational resolution in a PSF-map is expressed in metres.
3.51
overall gain
G
o
basic level of gain that is uniform for the whole scan area but modified by TGC relative to the
depth of the scan
3.52
profile line
set of pixel values ordered along an abscissa according to the sequence during their
acquisition
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 IEC 2017
3.53
lateral resolution in a PSF-map
Full-Width at Half-Maximum (FWHM) of the PSF, measured in a lateral direction
Note 1 to entry: The lateral resolution in a PSF-map differs from the lateral resolution specified by 3.17. It is
used for the PSF-mapping only to simplify the data acquisition.
Note 2 to entry: Detailed explanation of the method is in D.6.1.2.
Note 3 to entry: Lateral resolution in a PSF-map is expressed in metres.
3.54
measuring grid
matrix of points specified by Cartesian coordinates x and z defined in a plane parallel to the
i j
scanning plane
Note 1 to entry: Each point determines the position (x ,z ) in which individual measurement of PSF is performed.
i j
Note 2 to entry: The step ∆x is defined as an increment x – x in the lateral direction. The step ∆z is defined as
i+1 i
an increment z – z in the axial direction.
j+1 j
3.55
performance evaluation
tests performed to assess specific absolute performance of the object tested
Note 1 to entry: Typical times for ultrasound-system performance evaluation are at pre-purchase evaluation,
new- and repaired-system acceptance testing, at time of performance difficulties, and at end-of-useful-life
evaluations.
[SOURCE: IEC TS 62736:2016, 3.5]
3.56
precision
closeness of agreement between independent test results obtained under stipulated conditions
[SOURCE: ISO 5725-1:1994, 3.12]
3.57
scanning window
area on the surface of the test tank dedicated for transducer application to obtain a suitable
sonogram of the target
Note 1 to entry: It is important that the scanning window be covered by flexible foil made of material with similar
acoustic properties to the working liquid to avoid ultrasound field reflections and absorption.
Note 2 to entry: The foil flexibility should assure proper acoustical contact of any type of curved transducer.
Note 3 to entry: It is important that the foil covering the scanning-window be tough enough to prevent its damage
during coupling the measured transducer to the scanning window, to prevent resultant leakage of working liquid
from the measuring tank.
Note 4 to entry: The scanning window has the identical function as the test object scanning surface in the case
of tissue-mimicking test objects (see 3.34).
3.58
side-lobe signal
echo signal generated by ultrasound signal transmitted/received in a direction different from the
central axis of the transducer
3.59
test tank
tank designed to be suitable for providing specified kind of tests, which is filled with a working
liquid and equipped with scanning window(s)

 IEC 2017
4 Symbols
A surface area
A cross-sectional area
c
a length of the semi-major axes for a given half (i = 1 or 2) of the ellipsoid of an
i
ovoid object
A greatest a evaluated for whole measured volume
r,max r,max
a MER pixel value evaluated from ROI
r,max
a (x,y,z) MER pixel value evaluated from ROI scanned for reflector in position (x,y,z)
r,max
b mean of the lengths of the minor axes of the ellipsoid of an ovoid object
C contrast
D diameter of the reflector sphere
f acoustic working frequency
G overall gain
o
I(x,y,z) ROI specified in a digital picture of scan stored with reflector in position (x,y,z)
k circular wave number;( = 2π / λ in which λ is the wavelength)

m
M number of quantization levels defined by M = 2 where m is number of pixel bits
P perimeter of cross-section of ovoid object
p pixel size in lateral (azimuthal) direction

x
p pixel size in axial direction

z
R ratio of mean of measured spacings to known spacings (see 7.3.1)
R axial resolution in a PSF-map
A,PSF
R elevational resolution in a PSF-map
E,PSF
R lateral resolution in a PSF-map
L,PSF
R lateral dimension calibration factor (see 7.4.2);
x
ratio of mean filament spacings to known spacings for the horizontal direction
R ratio of mean filament spacings to known spacings for the vertical direction
y
r radius of a wire or filament target
V volume of an ovoid object
W value of FWHM (full width at half of maximum)

F,HM
W value of HWHM (half width at half of maximum)

H,HM
W normalized W according to Formula (D.3) in D.6.1.2
F,HM,n F,HM
W normalized W according to Formula (D.3) in D.6.1.2

H,HM,n H,HM
Z characteristic acoustic impedance of a wire or filament material
m
Z characteristic acoustic impedance of the surrounding medium (working liquid or
w
tissue-mimicking material)
λ ultrasound wavelength in the working liquid, calculated from the nominal
frequency of the transducer used
ε 1-(b/(2a)) eccentricity of an ellipsoid or an ovoid object
σ backscattering cross-section for a point-like target
ATGC automatic time-gain compensation
FWHM full width at half of maximum
HFHM half width at half of maximum

– 16 – IEC 61391-1:2006+AMD1:2017 CSV
 IEC 2017
LUT look-up table
MER maximum echo received
PSF point-spread function
RF radio frequency
ROI region of interest
TGC time-gain compensation
US ultrasound
5 General conditions
The tests should be performed within the following ambient conditions:
− temperature 23 °C ± 3 °C;
− relative humidity 45 % to 75 %;
− atmospheric pressure 86 kPa to 106 kPa.
This standard permits the use of test objects of various constructions. Therefore it is essential
that the following data of the test object be reported. The following standard choices are
recommended:
a) medium: either working liquid or tissue-mimicking material [6]
b) use of coupling gel: thin layer or gel with adapted sound velocity
c) geometry (one of the models given in Annex A, B or C, where needed with a different
spacing between targets).
For the medium working liquid, the following properties are required:
– speed of sound = (1 540 ± 15) m/s;
-1 -1
– low attenuation (< 0,1 f dB cm MHz );
– negligible scattering (see IEC 61685).
For adjusting the speed of sound in working liquid, see [7, 8].
For the medium tissue-mimicking material [9], the following properties are required:
− speed of sound = (1 540 ± 15) m/s;
–1 –1
− attenuation (0,5 ± 0,05) f dB cm MHz ) in the frequency range used in the tests;
− scattering (moderate, no value imposed ).
Note: Where an ultrasound system is designed for particular applications where the mean speed of sound is
different from 1 540 m/s, a medium with that design speed of sound should be employed and that change reported
with the results.
For tissue-mimicking properties, see also 6.4 and Annex D of IEC 61685:2001 .
Tissue-mimicking material is usually protected by a thin cover. Its thickness and acoustic
properties (attenuation and sound velocity) should be reported if these influence the
measurement.
The transducer is usually coupled to the cover of tissue-mimicking material by an acoustic
coupling agent (ultrasound gel). If the layer is thin (compared to the wavelength) its influence
can be ignored. For a thick layer, for example as needed for a curved-array transducer, the
sound velocity of the acoustic coupling agent shall be equal to (1 540 ± 15) m/s.
Sound velocity of a medium has two different effects: if it is larger then 1 540 m/s, the axial
distances in the medium are rendered proportionally shorter and the focus of the transducer

 IEC 2017
moves away from the transducer. If the sound velocity is lower, the opposite occurs. The effect
on the focus becomes more important for transducers with a high numeric aperture. Therefore
the use of the correct sound velocity (1 540 ± 15) m/s, to which ultrasonic systems are
standardized) is essential in Clauses 6 and 7, dealing with geometrical distortions. In Clause 8,
dealing with the PSF, a deviation can be tolerated for not too high numeric apertures.
In describing scanning procedures with “horizontal” and “vertical”, it is assumed that a test
object is insonated from above, and that the image on the scanner is oriented correspondingly.
6 Techniques for calibrating 2D-measurement systems
6.1 Test methods
To carry out the test procedures, the following items are required:
a) tissue-mimicking test objects containing targets at accurately specified positions;
b) tissue-mimicking test object containing a 3D-object of accurately specified dimensions;
c) a tank equipped with target holder to position the target at accurately specified
positions and containing degassed working liquid.
The specifications of these devices are given in the Annexes A, B, C and D.
6.2 Instruments
6.2.1 General
The equipment specified in this subclause has been selected to permit testing of ultrasonic
scanners in clinical usage. The devices described will ensure that the data collection and
analysis will be objective and reproducible.
6.2.2 Digitizers
While some spatial measurements can be made with long-existing digital callipers, for more
generally applicable, objective, reproducible data, the ultrasound images obtained for testing
should be digitally encoded. Many modern ultrasound imaging devices produce digital images
from the scan converter that can be used for these measurements and are most closely
representative of the displayed images. Such measurements can be employed well by hospital-
based users wi
...

NORME CEI
INTERNATIONALE
IEC
61391-1
INTERNATIONAL
Première édition
STANDARD
First edition
2006-07
Ultrasons – Scanners à impulsion et écho –
Partie 1:
Techniques pour l'étalonnage des systèmes
de mesure spatiaux et des mesures de la réponse
de la fonction de dispersion ponctuelle du système

Ultrasonics – Pulse-echo scanners –
Part 1:
Techniques for calibrating spatial measurement
systems and measurement of system point-spread
function response
Numéro de référence
Reference number
CEI/IEC 61391-1:2006
Numérotation des publications Publication numbering
Depuis le 1er janvier 1997, les publications de la CEI As from 1 January 1997 all IEC publications are
sont numérotées à partir de 60000. Ainsi, la CEI 34-1 issued with a designation in the 60000 series. For
devient la CEI 60034-1. example, IEC 34-1 is now referred to as IEC 60034-1.
Editions consolidées Consolidated editions
Les versions consolidées de certaines publications de la The IEC is now publishing consolidated versions of its
CEI incorporant les amendements sont disponibles. Par publications. For example, edition numbers 1.0, 1.1
exemple, les numéros d’édition 1.0, 1.1 et 1.2 indiquent and 1.2 refer, respectively, to the base publication,
respectivement la publication de base, la publication de the base publication incorporating amendment 1 and
base incorporant l’amendement 1, et la publication de the base publication incorporating amendments 1
base incorporant les amendements 1 et 2. and 2.
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NORME CEI
INTERNATIONALE
IEC
61391-1
INTERNATIONAL
Première édition
STANDARD
First edition
2006-07
Ultrasons – Scanners à impulsion et écho –
Partie 1:
Techniques pour l'étalonnage des systèmes
de mesure spatiaux et des mesures de la réponse
de la fonction de dispersion ponctuelle du système

Ultrasonics – Pulse-echo scanners –
Part 1:
Techniques for calibrating spatial measurement
systems and measurement of system point-spread
function response
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– 2 – 61391-1  CEI:2006
I
SOMMAIRE
AVANT-PROPOS .4
INTRODUCTION.8

1 Domaine d’application.10
2 Références normatives .10
3 Termes et définitions .10
4 Symboles.22
5 Conditions générales .22
6 Techniques d'étalonnage de systèmes de mesure 2D.26
6.1 Méthodes d’essai.26
6.2 Instruments .26
6.3 Réglages d’essai .28
6.4 Paramètres d’essai.30
7 Méthodes d'étalonnage des systèmes de mesure 3D.34
7.1 Généralités.34
7.2 Types de méthodes de reconstruction 3D.36
7.3 Paramètres d’essai associés aux problèmes de reconstruction.38
7.4 Méthodes d’essai pour la mesure de la précision de reconstruction 3D.40
8 Mesure des fonctions de dispersion ponctuelle et de dispersion linéaire (dimensions
de la zone de résolution à haut contraste) .48
8.1 Généralités.48
8.2 Méthodes d’essai.50
8.3 Instruments .50
8.4 Réglages d’essai .50
8.5 Paramètres d’essai.56

Annexe A (normative) Objets d’essai – Étalonnage de systèmes de mesure spatiaux 2D .66
Annexe B (normative) Objets d’essai – Mesure et étalonnage de la précision de
reconstruction d’images 3D .72
Annexe C (normative) Objets d’essai – Mesure de la réponse de la fonction de dispersion
ponctuelle .78

Bibliographie .88

61391-1  IEC:2006 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.9

1 Scope.11
2 Normative references.11
3 Terms and definitions .11
4 Symbols .23
5 General conditions.23
6 Techniques for calibrating 2D-measurement systems .27
6.1 Test methods .27
6.2 Instruments .27
6.3 Test settings.29
6.4 Test parameters .31
7 Methods for calibrating 3D-measurement systems.35
7.1 General .35
7.2 Types of 3D-reconstruction methods.37
7.3 Test parameters associated with reconstruction problems .39
7.4 Test methods for measurement of 3D-reconstruction accuracy.41
8 Measurement of point-spread and line-spread functions (high-contrast spot size) .49
8.1 General .49
8.2 Test methods .51
8.3 Instruments .51
8.4 Test settings.51
8.5 Test parameters .57

Annex A (normative) Test objects – Calibration of 2D-spatial measurement systems.67
Annex B (normative) Test objects – Measurement and calibration of 3D-image
reconstruction accuracy .73
Annex C (normative) Test objects – Measurement of point-spread function response.79

Bibliography .89

– 4 – 61391-1  CEI:2006
I
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
___________
ULTRASONS – SCANNERS À IMPULSION ET ÉCHO –

Partie 1: Techniques pour l'étalonnage des systèmes
de mesure spatiaux et des mesures de la réponse
de la fonction de dispersion ponctuelle du système

AVANT-PROPOS
1) La Commission Electrotechnique Internationale (CEI) est une organisation mondiale de normalisation composée
de l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a pour objet de
favoriser la coopération internationale pour toutes les questions de normalisation dans les domaines de
l'électricité et de l'électronique. A cet effet, la CEI – entre autres activités – publie des Normes internationales,
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La présente Norme internationale CEI 61391-1 a été établie par le comité d'études 87 de la CEI:
Ultrasons.
Le texte de cette norme est issu des documents suivants:
FDIS Rapport de vote
87/336/FDIS 87/343/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant
abouti à l'approbation de cette norme.
Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2.

61391-1  IEC:2006 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ULTRASONICS – PULSE-ECHO SCANNERS –

Part 1: Techniques for calibrating spatial measurement systems
and measurement of system point-spread function response

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,
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
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interested IEC National Committees.
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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.
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members of its technical committees and IEC National Committees for any personal injury, property damage or
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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 61391-1 has been prepared by IEC technical committee 87:
Ultrasonics.
The text of this standard is based on the following documents:
FDIS Report on voting
87/336/FDIS 87/343/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – 61391-1  CEI:2006
I
Les termes en caractères gras dans le texte sont définis à l'Article 3.
Cette norme est destinée à être publiée en deux parties ou plus:
– La Partie 1 traitant des techniques d'étalonnage des systèmes de mesure spatiaux et de
mesure de la réponse de la fonction de dispersion ponctuelle du système;
– La Partie 2 traitera du mesurage de la sensibilité du système, de la portée dynamique et de
la résolution à faible contraste.
Le comité a décidé que le contenu de cette publication ne sera pas modifié avant la date de
maintenance indiquée sur le site web de la CEI sous "http://webstore.iec.ch" dans les données
relatives à la publication recherchée. À cette date, la publication sera:
• reconduite;
• supprimée;
• remplacée par une édition révisée, ou
• amendée.
61391-1  IEC:2006 – 7 –
Terms in bold in the text are defined in clause 3.
This standard is intended to be published in two or more parts:
– Part 1 deals with techniques for calibrating spatial measurement systems and
measurement of system point-spread function response;
– Part 2 will deal with measurement of system sensitivity, dynamic range, and low-contrast
resolution.
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.
– 8 – 61391-1  CEI:2006
I
INTRODUCTION
Un scanner ultrasonique à impulsion et écho produit des images de tissus dans un plan de
balayage ultrasonique en balayant un faisceau pulsé étroit d’ultrasons à travers la section
examinée et en détectant les échos générés aux limites du tissu. De nombreux types de
transducteurs ultrasoniques fonctionnent en mode émetteur-récepteur pour les signaux
ultrasoniques. Les scanners ultrasoniques sont largement employés dans les applications
médicales, afin de produire des images d’organes à tissus mous du corps humain.
La présente norme décrit des procédures d’essai qui devraient être largement acceptables et
valides pour de nombreux types d’appareils. Il convient que les fabricants utilisent la norme
pour préparer leurs spécifications; il convient que les utilisateurs utilisent la norme pour vérifier
les spécifications. Les mesures peuvent être réalisées sans interférer avec les conditions de
fonctionnement normales de l’appareil. Des objets d’essai typiques sont décrits dans les
annexes. Les structures des objets d’essai n’ont pas été spécifiées en détail; des types de
structures générales et internes appropriés sont néanmoins décrits. Il est recommandé que la
structure spécifique de l’objet d’essai utilisée soit indiquée dans les résultats correspondants.
Des versions similaires commercialisées de ces objets d’essai sont disponibles.
Les paramètres de performance spécifiés et les méthodes de mesure correspondantes ont été
choisis pour fournir une base de comparaison avec les spécifications du fabricant et entre des
types d’appareils similaires de différentes marques, conçus pour les mêmes types d’appli-
cations diagnostiques. Il convient que les spécifications du fabricant permettent la comparaison
des résultats obtenus à partir des essais selon cette norme. En outre, l’objectif de la norme est
qu’un ensemble de résultats et de valeurs obtenus par l’utilisation des méthodes recom-
mandées fournisse des critères utiles de prédiction des performances des appareils pour des
applications diagnostiques appropriées. La présente norme s'intéresse en particulier aux
mesures sur les images par des techniques numériques. Des méthodes convenant à l'examen
visuel y sont également mentionnées. D'autres techniques visuelles peuvent être trouvées
1)
dans la CEI 61390 [1] .
Lorsqu’un système de diagnostic comporte plus d’une option pour un composant particulier du
système (par exemple le transducteur ultrasonique), l’objectif est que chaque option soit
considérée comme correspondant à un système différent. Toutefois, la performance d’une
machine est considérée comme spécifiée correctement, si des mesures sont réalisées pour les
combinaisons les plus significatives des réglages de contrôle et des accessoires de l’appareil.
Une évaluation additionnelle de l’appareil est manifestement possible, mais il convient qu'elle
ne soit envisagée que pour des cas particuliers et non de façon routinière.
___________
)
Les chiffres entre crochets renvoient à la bibliographie.

61391-1  IEC:2006 – 9 –
INTRODUCTION
An ultrasonic pulse-echo scanner produces images of tissue in an ultrasonic scan plane by
sweeping a narrow pulsed beam of ultrasound through the section of interest and detecting
the echoes generated at tissue boundaries. A variety of ultrasonic transducer types are
employed to operate in a transmit/receive mode for the ultrasonic signals. Ultrasonic scanners
are widely used in medical practice to produce images of many soft-tissue organs throughout
the human body.
This standard describes test procedures that should be widely acceptable and valid for a wide
range of types of equipment. Manufacturers should use the standard to prepare their
specifications; the users should employ the standard to check specifications. The
measurements can be carried out without interfering with the normal working conditions of the
machine. Typical test objects are described in the annexes. The structures of the test objects
have not been specified in detail, rather suitable types of overall and internal structures are
described. The specific structure of a test object should be reported with the results obtained
using it. Similar commercial versions of these test objects are available.
The performance parameters specified and the corresponding methods of measurement have
been chosen to provide a basis for comparison with the manufacturer's specification and
between similar types of apparatus of different makes, intended for the same kind of diagnostic
application. The manufacturer's specification should allow comparison with the results obtained
from the tests in this standard. Furthermore, it is intended that the sets of results and values
obtained from the use of the recommended methods will provide useful criteria for predicting
the performance of equipment in appropriate diagnostic applications. This standard
concentrates on measurements of images by digital techniques. Methods suitable for
inspection by eye are covered here as well. Discussion of other visual techniques can be found
1)
in IEC 61390 [1] .
Where a diagnostic system accommodates more than one option in respect of a particular
system component, for example the ultrasonic transducer, it is intended that each option be
regarded as a separate system. However, it is considered that the performance of a machine is
adequately specified, if measurements are undertaken for the most significant combinations of
machine control settings and accessories. Further evaluation of equipment is obviously
possible but this should be considered as a special case rather than a routine requirement.
___________
)
Figures in square brackets refer to the Bibliography.

– 10 – 61391-1  CEI:2006
I
ULTRASONS – SCANNERS À IMPULSION ET ÉCHO –

Partie 1: Techniques pour l'étalonnage des systèmes
de mesure spatiaux et des mesures de la réponse
de la fonction de dispersion ponctuelle du système

1 Domaine d’application
La présente Norme Internationale décrit des méthodes d'étalonnage des moyens de mesure
spatiaux et de la fonction de dispersion ponctuelle d’équipements d’imagerie à ultrasons,
dans la gamme des fréquences ultrasoniques s’étendant de 0,5 MHz à 15 MHz. La norme
s’applique aux scanners ultrasoniques basés sur le principe d’impulsion et écho des types
suivants:
− scanners sectoriels à balayage mécanique;
− scanners sectoriels électroniques à réseau de phase;
− scanners électroniques à réseau linéaire;
− scanners sectoriels électroniques à réseau courbe;
− scanners à bain d’eau, basé sur l’un des quatre mécanismes de balayage précédents;
− systèmes de reconstruction de volume en 3D.
2 Références normatives
Les documents de référence suivants sont indispensables pour l'application du présent
document. Pour les références datées, seule l'édition citée s'applique. Pour les références non
datées, la dernière édition du document de référence s'applique (y compris les éventuels
amendements).
CEI 61102:1991, Mesurage et caractérisation des champs ultrasonores à l'aide d'hydrophones
dans la gamme de fréquences de 0,5 MHz à 15 MHz
CEI 61685:2001, Ultrasons – Systèmes de mesure de débit – Montage pour essai de débit
(disponible en anglais seulement)
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions suivants s’appliquent.
Voir également les définitions et explications données dans les normes et les rapports
techniques connexes [1-5].
3.1
A-scan
classe de géométrie d’acquisition de données à une dimension, dans laquelle l’information de
puissance d’écho est acquise à partir de points disposés le long d’un axe de faisceau unique
et est affichée par l’amplitude en fonction du temps de parcours ou de la distance

61391-1  IEC:2006 – 11 –
ULTRASONICS – PULSE-ECHO SCANNERS –

Part 1: Techniques for calibrating spatial measurement systems
and measurement of system point-spread function response

1 Scope
This International Standard describes methods of calibrating the spatial measurement facilities
and point-spread function of ultrasonic imaging equipment in the ultrasonic frequency range
0,5 MHz to 15 MHz. This standard is relevant for ultrasonic scanners based on the pulse-echo
principle of the types listed below:
− mechanical sector scanners;
− electronic phased-array sector scanners;
− electronic linear-array scanners;
− electronic curved-array sector scanners;
− water-bath scanners based on any of the above four scanning mechanisms;
− 3D-volume reconstruction systems.
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.
IEC 61102:1991, Measurement and characterisation of ultrasonic fields using hydrophones in
the frequency range 0,5 MHz to 15 MHz

IEC 61685:2001, Ultrasonics – Flow measurement systems – Flow test object
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
See also related standards and technical reports for definitions and explanations. [1-5]
3.1
A-scan
class of data acquisition geometry in one dimension, in which echo strength information is
acquired from points lying along a single beam axis and displayed as amplitude versus time of
flight or distance
– 12 – 61391-1  CEI:2006
I
3.2
milieu de couplage acoustique (ou milieu de couplage)
substance – habituellement sous forme d’un gel ou autre fluide – utilisée pour assurer un
contact acoustique entre le transducteur et la peau du patient, ou entre le transducteur et la
surface d’un objet d’essai scellé
3.3
fréquence de fonctionnement acoustique
moyenne arithmétique des fréquences f et f auxquelles l’amplitude du spectre de pression
1 2
acoustique est de 3 dB sous le pic d’amplitude
(Voir CEI 61102, 3.4.2)
3.4
compensation temps-gain automatique
ATGC
commande temps-gain à fonctionnement automatique, basée sur l’observation de la diminution
des amplitudes d’écho due à l’atténuation de l’amplitude des impulsions ultrasoniques avec la
profondeur
3.5
résolution axiale
séparation minimale le long de l’axe de faisceau entre deux volumes à diffusion égale ou de
cibles à la profondeur spécifiée pour laquelle deux échos distincts peuvent être affichés
3.6
coefficient de rétrodiffusion
puissance acoustique moyenne diffusée à 180° de la direction d’un objet spécifié par rapport à
la direction du faisceau incident, en stéradian ou par unité de volume, divisée par l’intensité du
faisceau incident. Dans le cas d'un volume rempli de nombreux diffuseurs, la distribution de
ces derniers est considérée comme aléatoire. La puissance moyenne est obtenue à partir de
différentes réalisations spatiales du volume de dispersion
NOTE Le coefficient de rétrodiffusion est communément considéré comme étant le différentiel de la section
transversale de dispersion par unité de volume selon la direction de 180°.
3.7
contraste de rétrodiffusion (normalisé)
différence entre les coefficients de rétrodiffusion de deux régions définies, divisée par la
racine carrée du produit des deux coefficients de rétrodiffusion
3.8
axe de faisceau
axe longitudinal du motif de réponse à impulsion et écho d'une ligne de balayage en mode B
donnée, un équivalent impulsion et écho à l'axe de faisceau transmis de la CEI 61828 [2]
3.9
B-scan
classe de géométrie d’acquisition de données dans laquelle l’information d’écho est acquise à
partir de points disposés dans un plan de balayage ultrasonique contenant des faisceaux
ultrasoniques de balayage. Voir mode B ci-dessous.
NOTE B-scan est le terme en langage commun pour désigner un balayage ou une image en mode B. (Voir 3.10).

61391-1  IEC:2006 – 13 –
3.2
acoustic coupling agent (also, coupling agent)
a material, usually a gel or other fluid, that is used to ensure acoustic contact between the
transducer and the patient’s skin, or between the transducer and the surface of a sealed test
object
3.3
acoustic working frequency
arithmetic mean of the frequencies f and f at which the amplitude of the acoustic pressure
1 2
spectrum is 3 dB below the peak amplitude
(See 3.4.2 of IEC 61102)
3.4
automatic time-gain compensation
ATGC
automatic working time gain control based on the observed decrease in echo amplitudes due to
the attenuation in ultrasonic pulse amplitude with depth
3.5
axial resolution
minimum separation along the beam axis of two equally scattering volumes or targets at a
specified depth for which two distinct echo signals can be displayed
3.6
backscatter coefficient
mean acoustic power scattered in the 180º direction by a specified object with respect to the
direction of the incident beam, per unit solid angle per unit volume, divided by the incident
beam intensity. For a volume filled with many scatterers, the scatterers are considered to be
randomly distributed. The mean power is obtained from different spatial realisations of the
scattering volume
NOTE Backscatter coefficient is commonly referred to as the differential scattering cross-section per unit volume
in the 180° direction
3.7
backscatter contrast (normalized)
difference between the backscatter coefficients from two defined regions divided by the
square root of the product of the two backscatter coefficients
3.8
beam axis
the longitudinal axis of the pulse-echo response pattern of a given B-mode scan line, a
pulse-echo equivalent to the transmitted beam axis of IEC 61828 [2]
3.9
B-scan
class of data acquisition geometry in which echo information is acquired from points lying in an
ultrasonic scan plane containing interrogating ultrasonic beams. See B-mode below.
NOTE B-scan is a colloquial term for B-mode scan or image. (See 3.10)

– 14 – 61391-1  CEI:2006
I
3.10
affichage à luminosité modulée
mode B
méthode de présentation de l’information B-scan dans laquelle une section particulière à
travers un objet image est représentée de façon conforme par le plan de balayage de
l’affichage et dans laquelle l’amplitude d’écho est représentée par la luminosité locale ou la
densité optique de l’affichage
[CEI 60854: définition 3.18, modifiée]
3.11
plage dynamique affichée
rapport de l’amplitude de l’écho maximal ne saturant pas l’affichage à l’écho minimal pouvant
être distingué sur l’affichage dans les conditions d’essai du scanner, exprimé en décibels
3.12
résolution de profondeur
séparation minimale perpendiculaire au plan de balayage ultrasonique entre deux cibles à
diffusion égale, à la profondeur spécifiée, pour laquelle deux échos distincts peuvent être
affichés. Souvent utilisé ici de manière informelle relativement à l’épaisseur de tranche pour
les besoins du balayage 3D
3.13
champ de vision
surface du plan de balayage ultrasonique parcourue par le faisceau ultrasonique durant
l’acquisition des données d’écho pour la définition d’une image
3.14
fréquence de rafraîchissement
nombre de balayages de l’image entière effectués par le faisceau ultrasonique en une
seconde à travers le champ de vision
3.15
gain
rapport de la sortie à l’entrée d’un système, généralement supérieur à un (amplifié) et exprimé
en décibels
3.16
échelle de gris
gamme de valeurs de luminosité d’image. Elle peut être continue entre deux valeurs extrêmes
ou discontinue, au moins trois valeurs distinctes étant représentées
[CEI 60854: définition 3.14]
3.17
résolution latérale
séparation minimale de deux cibles linéaires à une profondeur spécifiée dans un objet
d’essai en matériau d'imitation du tissu, permettant d’afficher deux signaux d’écho distincts.
Il convient que les cibles linéaires soient perpendiculaires au plan balayé; il convient que la
séparation entre les cibles soit perpendiculaire à l'axe d'alignement du faisceau
3.18
fonction de dispersion linéaire
FDL
réponse caractéristique en trois dimensions d’un système d’imagerie à une cible linéaire à
haut contraste
61391-1  IEC:2006 – 15 –
3.10
Brightness-modulated display
B-mode
method of presentation of B-scan information in which a particular section through an imaged
object is represented in a conformal way by the scan plane of the display and echo amplitude is
represented by local brightness or optical density of the display
[IEC 60854: definition 3.18, modified]
3.11
displayed dynamic range
ratio, expressed in decibels, of the amplitude of the maximum echo that does not saturate the
display to the minimum echo that can be distinguished in the display under the scanner test
settings
3.12
elevational resolution
minimum separation perpendicular to the ultrasonic scan plane of two equally scattering
targets at a specified depth for which two distinct echo signals can be displayed. Often used
here informally for slice thickness for purposes of 3D-scanning
3.13
field-of-view
area in the ultrasonic scan plane which is insonated by the ultrasound beam during the
acquisition of echo data to produce one image frame
3.14
frame rate
number of sweeps comprising the full-frame refresh rate that the ultrasonic beam makes per
second through the field-of-view
3.15
gain
ratio of the output to the input of a system, generally an amplifying system, usually expressed
in decibels
3.16
grey scale
range of values of image brightness, being either continuous between two extreme values or, if
discontinuous, including at least three discrete values
[IEC 60854: definition 3.14]
3.17
lateral resolution
minimum separation of two line targets at a specified depth in a test object made of
tissue-mimicking material for which two distinct echo signals can be displayed. The line
targets should be perpendicular to the scanned plane; the separation between the targets
should be perpendicular to the beam-alignment axis
3.18
line-spread function
LSF
characteristic response in three dimensions of an imaging system to a high-contrast line target

– 16 – 61391-1  CEI:2006
I
3.19
cible linéaire
réflecteur cylindrique dont le diamètre est si petit qu'il ne peut pas être distingué par le
système d'imagerie d'un réflecteur cylindrique avec un diamètre d'un ordre de grandeur
inférieur, excepté par l'amplitude du signal. Il convient que la rétrodiffusion d'une cible linéaire
standard soit une fonction simple de la fréquence, sur la gamme des fréquences étudiées
3.20
mode M
mode en temps réel
méthode de présentation d’information M-scan dans laquelle le mouvement de structures le
long d’un axe de faisceau fixe est représenté par leurs positions sur une ligne se déplaçant en
travers de l’écran afin d’indiquer la variation temporelle de l’écho
3.21
M-scan
balayage en temps réel (time motion)
classe de géométrie d’acquisition dans laquelle l’information d’écho de structures en
mouvement est acquise à partir de points disposés le long d’un axe de faisceau unique.
L’information de puissance d’écho est présentée en affichage de mode M
3.22
fréquence nominale (d’un transducteur)
fréquence de fonctionnement acoustique prévue d'un transducteur telle que déclarée par le
concepteur ou par le fabricant
[adaptée de la définition 3.7 de la CEI 60854]
3.23
pixel
élément d’image
unité ou cellule spatiale la plus petite d’une image représentée par un réseau bidimensionnel
numérisé. Chaque pixel possède une adresse (coordonnées x et y correspondant à sa position
dans le réseau) et un niveau de luminosité spécifique
NOTE Pixel est une contraction de «picture element».
3.24
cible ponctuelle
réflecteur dont les dimensions de la surface de diffusion est si petite qu'il ne peut pas être
distingué (excepté par l'amplitude du signal), par le système d'imagerie, d'une cible similaire
dont la surface de diffusion est d'un ordre de grandeur inférieur. Il convient que la section
transversale de la rétrodiffusion d'une cible ponctuelle standard soit une fonction simple de la
fréquence, sur la gamme des fréquences étudiées
3.25
fonction de dispersion ponctuelle
FDP
réponse caractéristique en trois dimensions d’un système d’imagerie à une cible ponctuelle à
haut contraste
NOTE Pour la plupart des systèmes ultrasoniques, une FDP ultrasonique individuelle ne peut pas être utilisée
comme réponse d’impulsion générale du système, du fait des variations de la FDP avec la profondeur, avec
d'autres positions dans la région d'utilisation et avec les réglages de mise au point et de fréquence du système.

61391-1  IEC:2006 – 17 –
3.19
line target
cylindrical reflector whose diameter is so small that the reflector cannot be distinguished by the
imaging system from a cylindrical reflector with diameter an order of magnitude smaller, except
by signal amplitude. The backscatter from a standard line target should be a simple function
of frequency over the range of frequencies studied
3.20
M-mode
time-motion mode
method of presentation of M-scan information in which the motion of structures along a fixed
beam axis is depicted by presenting their position
...

IEC 61391-1 ®
Edition 1.1 2017-07
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Ultrasonics – Pulse-echo scanners –
Part 1: Techniques for calibrating spatial measurement systems and
measurement of system point-spread function response

Ultrasons – Scanners à impulsion et écho –
Partie 1: Techniques pour l'étalonnage des systèmes de mesure spatiaux et
des mesures de la réponse de la fonction de dispersion ponctuelle du système
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IEC 61391-1 ®
Edition 1.1 2017-07
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Ultrasonics – Pulse-echo scanners –

Part 1: Techniques for calibrating spatial measurement systems and

measurement of system point-spread function response

Ultrasons – Scanners à impulsion et écho –

Partie 1: Techniques pour l'étalonnage des systèmes de mesure spatiaux et

des mesures de la réponse de la fonction de dispersion ponctuelle du système

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.140.50 ISBN 978-2-8322-4589-7

IEC 61391-1 ®
Edition 1.1 2017-07
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Ultrasonics – Pulse-echo scanners –
Part 1: Techniques for calibrating spatial measurement systems and
measurement of system point-spread function response

Ultrasons – Scanners à impulsion et écho –
Partie 1: Techniques pour l'étalonnage des systèmes de mesure spatiaux et
des mesures de la réponse de la fonction de dispersion ponctuelle du système

– 2 – IEC 61391-1:2006+AMD1:2017 CSV
 IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
4 Symbols and abbreviated terms . 15
5 General conditions . 16
6 Techniques for calibrating 2D-measurement systems . 17
6.1 Test methods . 17
6.2 Instruments . 17
6.3 Test settings . 18
6.4 Test parameters . 19
7 Methods for calibrating 3D-measurement systems . 21
7.1 General . 21
7.2 Types of 3D-reconstruction methods . 21
7.3 Test parameters associated with reconstruction problems . 22
7.4 Test methods for measurement of 3D-reconstruction accuracy . 23
8 Measurement of point-spread and line-spread functions (high-contrast spot size) . 27
8.1 General . 27
8.2 Test methods . 28
8.3 Instruments . 28
8.4 Test settings . 29
8.5 Test parameters . 31
Annex A (normative) Test objects – Calibration of 2D-spatial measurement systems . 36
Annex B (normative) Test objects – Measurement and calibration of 3D-image
reconstruction accuracy . 39
Annex C (normative) Test objects – Measurement of point-spread function response . 43
Annex D (informative) Quality parameters derived by PSF-mapping analysis . 48
Bibliography . 64

Figure A.1 – Concentric circular arrays of nylon filaments . 37
Figure A.2 – Regular 2D-array of nylon filaments . 38
Figure B.1 – Tissue mimicking ovoid target phantom . 40
Figure B.2 – Composite of two cross-sectional views of test object shown in Figure B.1 . 40
Figure B.3 – Projection view from top of test object shown in Figure B.1 . 41
Figure B.4 – Projection view from end window of test object shown in Figure B.1 . 42
Figure C.1 – Filament test object for measuring the LSF . 44
Figure C.2 – Axial resolution test object . 45
Figure C.3 – Movable single filament in water . 46
Figure C.5 – Slice thickness measurement and calculation . 47
Figure D.1 – Principal schematic of the PSF-analyser function . 51
Figure D.2 – Principle of elimination of internal multi-reflections in the spherical target
using filtration in time domain . 54

 IEC 2017
Figure D.3 – A pixel maximum level and PSF-trace estimation in ROI stored digital data . 56
Figure D.4 – The derivation of FWHM-value from the lateral-amplitude profile of PSF
received-echo signal (a (x ,z ) = 221) with reflector positioned on axis of the
r,max i k
ultrasound beam in point (x ,z ) of the measuring grid . 57
i k
Figure D.5 – The FWHM-derivation from the elevational (transversal) profile of MER in
one point of the measuring grid . 58
Figure D.6 – The derivation of the reflected-signal axial-profile from the ROI . 59
Figure D.7 – The enumeration of the W parameter from the axial-profile line:
H,HM
a (x,z) = 243 . 59
r,max
Figure D.8 – The distribution of FWHM over a scan area of width 20 mm to depth 80
mm, made with a monofocal scan using a linear 5 MHz transducer . 60
Figure D.9 – The distribution of FWHM over a scan area of width 20 mm to depth 80
mm, made with the same system as for Figure D.7 but using three focal points (F1, F2
and F3) for the scan . 60
Figure D.10 – Plot of the distribution of MER-intensity over the scanning area 30 mm
wide and 40 mm deep . 61
Figure D.11 – The elevational profile recorded from a (x ,y,z ) values for a spherical
r,max i k
target passing perpendicularly to the scanning plane in one point (x ,z ) of the
i k
measuring grid . 62

Table 1 – Expected values for the two ellipsoidal objects in Figure B.3 . 27
Table 2 – Suggested table of reported values . 27

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 IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ULTRASONICS – PULSE-ECHO SCANNERS –
Part 1: Techniques for calibrating spatial measurement systems
and measurement of system point-spread function response
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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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
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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.
This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 61391-1 edition 1.1 contains the first edition (2006-07) [documents 87/336/FDIS and 87/343/
RVD] and its amendment 1 (2017-07) [documents 87/650/FDIS and 87/653/RVD].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text.
A separate Final version with all changes accepted is available in this publication.

 IEC 2017
International Standard IEC 61391-1 has been prepared by IEC technical committee 87:
Ultrasonics.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
Terms in bold in the text are defined in clause 3.
This standard is intended to be published in two or more parts:
– Part 1 deals with techniques for calibrating spatial measurement systems and
measurement of system point-spread function response;
– Part 2 will deal with measurement of system sensitivity, dynamic range, and low-contrast
resolution.
The committee has decided that the contents of the base publication and its amendment 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.
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.

– 6 – IEC 61391-1:2006+AMD1:2017 CSV
 IEC 2017
INTRODUCTION
An ultrasonic pulse-echo scanner produces images of tissue in an ultrasonic scan plane by
sweeping a narrow pulsed beam of ultrasound through the section of interest and detecting
the echoes generated at tissue boundaries. A variety of ultrasonic transducer types are
employed to operate in a transmit/receive mode for the ultrasonic signals. Ultrasonic scanners
are widely used in medical practice to produce images of many soft-tissue organs throughout
the human body.
This standard describes test procedures that should be widely acceptable and valid for a wide
range of types of equipment. Manufacturers should use the standard to prepare their
specifications; the users should employ the standard to check specifications. The
measurements can be carried out without interfering with the normal working conditions of the
machine. Typical test objects are described in the annexes. The structures of the test objects
have not been specified in detail, rather suitable types of overall and internal structures are
described. The specific structure of a test object should be reported with the results obtained
using it. Similar commercial versions of these test objects are available.
The performance parameters specified and the corresponding methods of measurement have
been chosen to provide a basis for comparison with the manufacturer's specification and
between similar types of apparatus of different makes, intended for the same kind of diagnostic
application. The manufacturer's specification should allow comparison with the results obtained
from the tests in this standard. Furthermore, it is intended that the sets of results and values
obtained from the use of the recommended methods will provide useful criteria for predicting
the performance of equipment in appropriate diagnostic applications. This standard
concentrates on measurements of images by digital techniques. Methods suitable for
inspection by eye are covered here as well. Discussion of other visual techniques can be found
1)
in IEC 61390 [1] .
Where a diagnostic system accommodates more than one option in respect of a particular
system component, for example the ultrasonic transducer, it is intended that each option be
regarded as a separate system. However, it is considered that the performance of a machine is
adequately specified, if measurements are undertaken for the most significant combinations of
machine control settings and accessories. Further evaluation of equipment is obviously
possible but this should be considered as a special case rather than a routine requirement.
___________
)
Figures in square brackets refer to the Bibliography.

 IEC 2017
ULTRASONICS – PULSE-ECHO SCANNERS –

Part 1: Techniques for calibrating spatial measurement systems
and measurement of system point-spread function response

1 Scope
This International Standard describes methods of calibrating the spatial measurement facilities
and point-spread function of ultrasonic imaging equipment in the ultrasonic frequency range
0,5 MHz to 15 MHz. This standard is relevant for ultrasonic scanners based on the pulse-echo
principle of the types listed below:
− mechanical sector scanners;
− electronic phased-array sector scanners;
− electronic linear-array scanners;
− electronic curved-array sector scanners;
− water-bath scanners based on any of the above four scanning mechanisms;
− 3D-volume reconstruction systems.
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.
IEC 60050-801:1994, International Electrotechnical Vocabulary – Chapter 801: Acoustics and
electroacoustics
IEC 60050-802:2011, International Electrotechnical Vocabulary – Part 802: Ultrasonics
IEC 61102:1991, Measurement and characterisation of ultrasonic fields using hydrophones in
the frequency range 0,5 MHz to 15 MHz
IEC 61685:2001, Ultrasonics – Flow measurement systems – Flow test object
IEC 62127-1:2007, Ultrasonics – Hydrophones – Part 1: Measurement and characterization of
medical ultrasonic fields up to 40 MHz
3 Terms and definitions
For the purposes of this document, the following terms and definitions given in IEC 60050-
801:1994, IEC 60050-802:2011, IEC 62127-1:2007 and the following apply. See also related
International Standards, Technical Specifications and Technical Reports for definitions and
explanations [1-5] [1] [2] [3] [4] [34] [35] [36] [37] [38] [39].
3.1
A-scan
class of data acquisition geometry in one dimension, in which echo strength information is
acquired from points lying along a single beam axis and displayed as amplitude versus time of
flight or distance
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 IEC 2017
3.2
acoustic coupling agent (also, coupling agent)
a material, usually a gel or other fluid, that is used to ensure acoustic contact between the
transducer and the patient’s skin, or between the transducer and the surface of a sealed test
object
3.3
acoustic working frequency
arithmetic mean of the frequencies f and f at which the amplitude of the acoustic pressure
1 2
spectrum is 3 dB below the peak amplitude
(See 3.4.2 of IEC 61102)
3.4
automatic time-gain compensation
ATGC
automatic working time gain control based on the observed decrease in echo amplitudes due to
the attenuation in ultrasonic pulse amplitude with depth
3.5
axial resolution
minimum separation along the beam axis of two equally scattering volumes or targets at a
specified depth for which two distinct echo signals can be displayed
3.6
backscatter coefficient
mean acoustic power scattered in the 180º direction by a specified object with respect to the
direction of the incident beam, per unit solid angle per unit volume, divided by the incident
beam intensity. For a volume filled with many scatterers, the scatterers are considered to be
randomly distributed. The mean power is obtained from different spatial realisations of the
scattering volume
NOTE Backscatter coefficient is commonly referred to as the differential scattering cross-section per unit volume
in the 180° direction
3.7
backscatter contrast (normalized)
difference between the backscatter coefficients from two defined regions divided by the
square root of the product of the two backscatter coefficients
3.8
beam axis
the longitudinal axis of the pulse-echo response pattern of a given B-mode scan line, a
pulse-echo equivalent to the transmitted beam axis of IEC 61828 [2]
3.9
B-scan
class of data acquisition geometry in which echo information is acquired from points lying in an
ultrasonic scan plane containing interrogating ultrasonic beams. See B-mode below.
NOTE B-scan is a colloquial term for B-mode scan or image. (See 3.10)
3.10
Brightness-modulated display
B-mode
method of presentation of B-scan information in which a particular section through an imaged
object is represented in a conformal way by the scan plane of the display and echo amplitude is
represented by local brightness or optical density of the display
[IEC 60854: definition 3.18, modified]

 IEC 2017
3.11
displayed dynamic range
ratio, expressed in decibels, of the amplitude of the maximum echo that does not saturate the
display to the minimum echo that can be distinguished in the display under the scanner test
settings
3.12
elevational resolution
minimum separation perpendicular to the ultrasonic scan plane of two equally scattering
targets at a specified depth for which two distinct echo signals can be displayed. Often used
here informally for slice thickness for purposes of 3D-scanning
3.13
field-of-view
area in the ultrasonic scan plane which is insonated by the ultrasound beam during the
acquisition of echo data to produce one image frame
3.14
frame rate
number of sweeps comprising the full-frame refresh rate that the ultrasonic beam makes per
second through the field-of-view
3.15
gain
ratio of the output to the input of a system, generally an amplifying system, usually expressed
in decibels
3.16
grey scale
range of values of image brightness, being either continuous between two extreme values or, if
discontinuous, including at least three discrete values
[IEC 60854: definition 3.14]
3.17
lateral resolution
minimum separation of two line targets at a specified depth in a test object made of
tissue-mimicking material for which two distinct echo signals can be displayed. The line
targets should be perpendicular to the scanned plane; the separation between the targets
should be perpendicular to the beam-alignment axis
3.18
line-spread function
LSF
characteristic response in three dimensions of an imaging system to a high-contrast line target
3.19
line target
cylindrical reflector whose diameter is so small that the reflector cannot be distinguished by the
imaging system from a cylindrical reflector with diameter an order of magnitude smaller, except
by signal amplitude. The backscatter from a standard line target should be a simple function
of frequency over the range of frequencies studied

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 IEC 2017
3.20
M-mode
time-motion mode
method of presentation of M-scan information in which the motion of structures along a fixed
beam axis is depicted by presenting their positions on a line which moves across a display to
show the variation with time of the echo
3.21
M-scan
time-motion scan
class of acquisition geometry in which echo information from moving structures is acquired
from points lying along a single beam axis. The echo strength information is presented using
an M-mode display
3.22
nominal frequency (of a transducer)
intended acoustic working frequency of a transducer as quoted by the designer or
manufacturer
[adapted from definition 3.7 of IEC 60854]
3.23
pixel
picture element
smallest spatial unit or cell size of a digitized 2-dimensional array representation of an image.
Each pixel has an address (x-and y-coordinates corresponding to its position in the array) and
a specific brightness level
NOTE Pixel is a contraction of ‘picture element’.
3.24
point target
reflector whose scattering surface dimensions are so small that it cannot be distinguished
(except by signal amplitude) by the imaging system from a similar target whose scattering
surface is an order of magnitude smaller. The backscatter cross section of a standard point
target should be a simple function of frequency over the range of frequencies studied.
3.25
point-spread function
PSF
characteristic response in three dimensions of an imaging system to a high-contrast point
target.
NOTE For most ultrasound systems, an individual ultrasound PSF cannot be used as the overall system impulse
response, due to changes in the PSF with depth, with other positions in the region of use and with system focal and
frequency settings. The problem is solved by PSF mapping – see Annex D.
3.26
scan line
one of the component lines which form a B-mode image on an ultrasound monitor. Each line is
the envelope-detected A-scan line in which the echo amplitudes are converted to brightness
values
3.27
scan plane
a plane containing the ultrasonic scan lines
[IEC 61102: definition 3.38, modified]

 IEC 2017
3.28
side lobe
secondary beam, generated by an ultrasonic transducer, that deviates from the direction of
the main beam. Usually, the intensity of the side lobes is significantly less than that of the
central axis beam
NOTE The presence of side lobes may be responsible for introducing artifactual echoes into the ultrasound
image.
3.29
slice thickness
thickness, perpendicular to the ultrasonic scan plane and at a stated depth in the test object,
of that region of the test object from which acoustic information is displayed
3.30
speckle pattern
image pattern or texture, produced by the interference of echoes from the scattering centres in
tissue or tissue-mimicking material
3.31
spot size
the –6 dB width or otherwise specified width of the PSF or LSF
3.32
target
an object to be interrogated by an ultrasound beam
NOTE Examples of targets are:
a) a device specifically designed to be inserted into the ultrasonic field to serve as the object on which the
radiation force is to be measured;
b) a scatterer or ensemble of scatterers giving rise to a signal within the effective ultrasonic beam;
c) a wire or a filament in a test object.
3.33 test object
device containing one or more groups of object configurations embedded in a tissue-
mimicking material or another medium
3.34 test object scanning surface
surface on the tissue-mimicking test object recommended for transducer location during a test
procedure
3.35
time-gain compensation
TGC
change in amplifier gain with time, introduced to compensate for loss in echo amplitude with
increasing depth due to attenuation in tissue
3.36
tissue-mimicking material
material in which the propagation velocity (speed of sound), reflecting, scattering and
attenuating properties are similar to those of soft tissue for ultrasound in the frequency range
0,5 MHz to 15 MHz.
[See 6.4 and Annex D of IEC 61685]
3.37
transmitted ultrasound field
three-dimensional distribution of ultrasound energy emanating from the ultrasonic transducer

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 IEC 2017
3.38
ultrasonic scan line
for automatic scanning systems, the beam-alignment axis either for a particular ultrasonic
transducer element or for a single or multiple excitation of an ultrasonic transducer or of an
ultrasonic transducer element group
[IEC 61157: definition 3.27, modified]
3.39
ultrasonic transducer
device capable of converting electrical energy to mechanical energy within the ultrasonic
frequency range and/or reciprocally capable of converting mechanical energy to electrical
energy
[IEC 61102: definition 3.58]
NOTE For the purposes of this standard, ultrasonic transducer is taken to refer to a complete assembly that
includes the transducer element or elements and mechanical and electrical damping and matching provisions.
3.40
ultrasonic transducer element group
group of elements of an ultrasonic transducer which are excited together in order to produce
a single acoustic pulse
[IEC 61102: definition 3.60]
3.41
ultrasound
acoustic oscillation whose frequency is above the high-frequency limit of audible sound
(conventionally 20 kHz)
[IEV 801 21-04, modified]
3.42
ultrasound beam (pulse-echo response pattern)
region adjacent to the transducer face from which an echo signal from a specified target may
be detected for the test settings of the scanner and with the scanner operating in a
non-scanning mode. This term should be distinguished from the transmitted ultrasound field
3.43
voxel
smallest spatial unit or cell size of a digitized 3-dimensional array representation of an image.
Each voxel has an address (x, y, and z-coordinates) corresponding to its position in the array,
and a specific brightness and/or color value
3.44
working liquid
a mixture of water and other solvent that adjusts the speed of sound to 1 540 m/s
[See also 6.4 and Annex D of IEC 61685:2001]
3.45
accuracy
closeness of agreement between a test result and the accepted reference value
[SOURCE: ISO 5725-1:1994, 3.6]
3.46
axial resolution in a PSF-map
twice the Half-Width-at-Half-Maximum (HWHM) of a function’s trace created from a set of
increasing pixel values, commencing near zero and terminating at the first maximum value

 IEC 2017
(centre of the PSF) and representing the leading edge of the echo signal from a point reflector
located on the main beam axis
Note 1 to entry: The axial resolution in a PSF map differs from the axial resolution specified by 3.5. It is used
for the PSF-mapping only to simplify the data acquisition.
Note 2 to entry: A detailed explanation of the axial resolution in the PSF-map measuring method is in D.6.1.4.
Note 3 to entry: The axial resolution mainly depends on the ultrasound frequency used, not on sonograph
construction.
Note 4 to entry: Axial resolution in a PSF-map is expressed in metres.
3.47
brightness
luminance as perceived by the human visual system
[SOURCE: IEC 62563-1:2009, 3.1.2]
3.48
contrast
C
ratio of the difference of the luminance of two image areas, L − L , divided by the average of
1 2
the two luminance values:
C = 2 (L − L )/(L + L )
1 2 1 2
[SOURCE: IEC 62563-1:2009, 3.1.6]
3.49
dynamic imaging
real-time imaging
imaging with a frame rate that is high enough to observe moving structures in apparently
continuous motion
3.50
elevational resolution in a PSF-map
difference of point-reflector displacements in passing through the scanning plane in an
elevational direction, which result in decreases of MER of −6 dB compared to the MER-value in
the beam centre
Note 1 to entry: The elevational resolution in a PSF-map differs from the elevational resolution specified by
3.12. It is used for the PSF-mapping only to simplify the data acquisition.
Note 2 to entry: Detailed explanation of the method is in D.6.1.3.
Note 3 to entry: Elevational resolution in a PSF-map is expressed in metres.
3.51
overall gain
G
o
basic level of gain that is uniform for the whole scan area but modified by TGC relative to the
depth of the scan
3.52
profile line
set of pixel values ordered along an abscissa according to the sequence during their
acquisition
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 IEC 2017
3.53
lateral resolution in a PSF-map
Full-Width at Half-Maximum (FWHM) of the PSF, measured in a lateral direction
Note 1 to entry: The lateral resolution in a PSF-map differs from the lateral resolution specified by 3.17. It is
used for the PSF-mapping only to simplify the data acquisition.
Note 2 to entry: Detailed explanation of the method is in D.6.1.2.
Note 3 to entry: Lateral resolution in a PSF-map is expressed in metres.
3.54
measuring grid
matrix of points specified by Cartesian coordinates x and z defined in a plane parallel to the
i j
scanning plane
Note 1 to entry: Each point determines the position (x ,z ) in which individual measurement of PSF is performed.
i j
Note 2 to entry: The step ∆x is defined as an increment x – x in the lateral direction. The step ∆z is defined as
i+1 i
an increment z – z in the axial direction.
j+1 j
3.55
performance evaluation
tests performed to assess specific absolute performance of the object tested
Note 1 to entry: Typical times for ultrasound-system performance evaluation are at pre-purchase evaluation,
new- and repaired-system acceptance testing, at time of performance difficulties, and at end-of-useful-life
evaluations.
[SOURCE: IEC TS 62736:2016, 3.5]
3.56
precision
closeness of agreement between independent test results obtained under stipulated conditions
[SOURCE: ISO 5725-1:1994, 3.12]
3.57
scanning window
area on the surface of the test tank dedicated for transducer application to obtain a suitable
sonogram of the target
Note 1 to entry: It is important that the scanning window be covered by flexible foil made of material with similar
acoustic properties to the working liquid to avoid ultrasound field reflections and absorption.
Note 2 to entry: The foil flexibility should assure proper acoustical contact of any type of curved transducer.
Note 3 to entry: It is important that the foil covering the scanning-window be tough enough to prevent its damage
during coupling the measured transducer to the scanning window, to prevent resultant leakage of working liquid
from the measuring tank.
Note 4 to entry: The scanning window has the identical function as the test object scanning surface in the case
of tissue-mimicking test objects (see 3.34).
3.58
side-lobe signal
echo signal generated by ultrasound signal transmitted/received in a direction different from the
central axis of the transducer
3.59
test tank
tank designed to be suitable for providing specified kind of tests, which is filled with a working
liquid and equipped with scanning window(s)

 IEC 2017
4 Symbols and abbreviated terms
A surface area
A cross-sectional area
c
a length of the semi-major axes for a given half (i = 1 or 2) of the ellipsoid of an
i
ovoid object
A greatest a evaluated for whole measured volume
r,max r,max
a MER pixel value evaluated from ROI
r,max
a (x,y,z) MER pixel value evaluated from ROI scanned for reflector in position (x,y,z)
r,max
b mean of the lengths of the minor axes of the ellipsoid of an ovoid object
C contrast
D diameter of the reflector sphere
f acoustic working frequency
G overall gain
o
I(x,y,z) ROI specified in a digital picture of scan stored with reflector in position (x,y,z)
k circular wave number;( = 2π / λ in which λ is the wavelength)

m
M number of quantization levels defined by M = 2 where m is number of pixel bits
P perimeter of cross-section of ovoid object
p pixel size in lateral (azimuthal) direction

x
p pixel size in axial direction

z
R ratio of mean of measured spacings to known spacings (see 7.3.1)
R axial resolution in a PSF-map
A,PSF
R elevational resolution in a PSF-map
E,PSF
R lateral resolution in a PSF-map
L,PSF
R lateral dimension calibration factor (see 7.4.2);
x
ratio of mean filament spacings to known spacings for the horizontal direction
R ratio of mean filament spacings to known spacings for the vertical direction
y
r radius of a wire or filament target
V volume of an ovoid object
W value of FWHM (full width at half of maximum)

F,HM
W value of HWHM (half width at half of maximum)

H,HM
W normalized W according to Formula (D.3) in D.6.1.2
F,HM,n F,HM
W normalized W according to Formula (D.3) in D.6.1.2

H,HM,n H,HM
Z characteristic acoustic impedance of a wire or filament material
m
Z characteristic acoustic impedance of the surrounding medium (working liquid or
w
tissue-mimicking material)
λ ultrasound wavelength in the working liquid, calculated from the nominal
frequency of the transducer used
ε 1-(b/(2a)) eccentricity of an ellipsoid or an ovoid object
σ backscattering cross-section for a point-like target
ATGC automatic time-gain compensation
FWHM full width at half of maximum
HFHM half width at half of maximum

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 IEC 2017
LUT look-up table
MER maximum echo received
PSF point-spread function
RF radio frequency
ROI region of interest
TGC time-gain compensation
US ultrasound
5 General conditions
The tests should be performed within the following ambient conditions:
− temperature 23 °C ± 3 °C;
− relative humidity 45 % to 75 %;
− atmospheric pressure 86 kPa to 106 kPa.
This standard permits the use of test objects of various constructions. Therefore it is essential
that the following data of the test object be reported. The following standard choices are
recommended:
a) medium: either working liquid or tissue-mimicking material [6]
b) use of coupling gel: thin layer or gel with adapted sound velocity
c) geometry (one of the models given in Annex A, B or C, where needed with a different
spacing between targets).
For the medium working liquid, the following properties are required:
– speed of sound = (1 540 ± 15) m/s;
-1 -1
– low attenuation (< 0,1 f dB cm MHz );
– negligible scattering (see IEC 61
...