IEC 61846:1998

INTERNATIONAL IEC
STANDARD 61846
First edition
1998-04
Ultrasonics –
Pressure pulse lithotripters –
Characteristics of fields
Ultrasons –
Lithotripteurs à ondes de pression –
Caractérisation des champs
Reference number
Numbering
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60000 series.
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thus ensuring that the content reflects current technology.
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Information on the subjects under consideration and work in progress undertaken by
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Terminology, graphical and letter symbols
For general terminology, readers are referred to IEC 60050: International
Electrotechnical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for
general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols
for diagrams.
* See web site address on title page.

INTERNATIONAL IEC
STANDARD 61846
First edition
1998-04
Ultrasonics –
Pressure pulse lithotripters –
Characteristics of fields
Ultrasons –
Lithotripteurs à ondes de pression –
Caractérisation des champs
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– 2 – 61846 © IEC:1998(E)
CONTENTS
Page
FOREWORD . 3
INTRODUCTION . 4
Clause
1 Scope. 5
2 Normative references. 5
3 Definitions. 6
4 List of symbols. 10
5 Conditions of measurement . 10
6 Test equipment. 11
6.1 Test chamber. 11
6.2 Hydrophone . 11
6.3 Voltage measurement . 12
7 Measurement procedure. 12
7.1 Spatial measurements . 12
7.2 Temporal measurements . 14
7.3 Acoustic energy measurements. 14
Annexes
A Acoustic wave lithotripsy. 16
B Types of pressure wave transducers . 18
C Field measurement . 20
D Bibliography. 25

61846 © IEC:1998(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ULTRASONICS –
PRESSURE PULSE LITHOTRIPTERS –
CHARACTERISTICS OF FIELDS
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61846 has been prepared by IEC technical committee 87:
Ultrasonics.
The text of this standard is based on the following documents:
FDIS Report on voting
87/115/FDIS 87/118/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.
Annexes A, B, C and D are for information only.
In this standard, the following print types are used:
– requirements and definitions: in roman type;
– NOTES: in smaller roman type;
– compliance: in italic type;
– terms used throughout this standard which have been defined in clause 3: small case
roman bold type.
A bilingual version of this standard may be issued at a later date.

– 4 – 61846 © IEC:1998(E)
INTRODUCTION
Extracorporeal lithotripsy is used for the clinical treatment of renal, ureteric and biliary stones.
Lithotripsy employs high-intensity acoustic waves to produce disintegration of the stones
through a process of sequential application of pressure waves. Several different forms of
lithotripsy equipment are now commercially available from a number of manufacturers.
This International Standard specifies methods of measuring and characterizing the acoustic
pressure field generated by lithotripsy equipment.

61846 © IEC:1998(E) – 5 –
ULTRASONICS –
PRESSURE PULSE LITHOTRIPTERS –
CHARACTERISTICS OF FIELDS
1 Scope
This International Standard is applicable to
– lithotripsy equipment using extracorporeally induced pressure waves;
– lithotripsy equipment producing focused mechanical energy.
This International Standard does not apply to percutaneous and laser lithotripsy equipment.
This International Standard specifies
– measurable parameters which could be used in the declaration of the acoustic output of
extracorporeal lithotripsy equipment,
– methods of measurement and characterization of the pressure field generated by
lithotripsy equipment.
NOTE – The parameters defined in this International Standard do not – at the present time – allow quantitative
statements to be made about effectiveness and possible hazard. In particular, it is not possible to make a
statement about the limits for these effects.
While this particular standard has been developed for equipment intended for use in
lithotripsy, it has been developed such that, as long as no other specific standards are
available to be used for other medical applications of therapeutic extracorporeal pressure
pulse equipment, this standard may be used as a guideline.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this International Standard. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties to
agreements based on this International Standard are encouraged to investigate the possibility
of applying the most recent editions of the normative documents indicated below. Members of
IEC and ISO maintain registers of currently valid International Standards.
IEC 60050(801):1994, International Electrotechnical Vocabulary (IEV) – Chapter 801: Acoustics
and electroacoustics
IEC 60866:1987, Characteristics and calibration of hydrophones for operation in the frequency
range 0,5 MHz to 15 MHz
IEC 61102:1991, Measurement and characterisation of ultrasonic fields using hydrophones in
the frequency range 0,5 MHz to 15 MHz

– 6 – 61846 © IEC:1998(E)
3 Definitions
For the purpose of this International Standard, the following definitions apply.
3.1 acoustic pulse energy
3.1.1
derived acoustic pulse energy
spatial integral of the derived pulse-intensity integral over a circular cross-sectional area of
radius R in the x-y plane which contains the focus
Symbol: E
R
Unit: joule, J
3.1.2
derived focal acoustic pulse energy
spatial integral of the derived pulse-intensity integral over the focal cross-sectional area
Symbol: E
f
Unit: joule, J
NOTE – This definition may overestimate E if the aperture of the pressure pulse generator is large.
3.2
beam axis
line passing through the geometric centre of the aperture of the pressure pulse generator and
the focus
NOTE – This line is taken as the z axis. See 6.1 and clause 7.
3.3
compressional pulse duration
time interval beginning at the first time the instantaneous acoustic pressure exceeds 50 % of
the peak-positive acoustic pressure and ending at the next time the instantaneous
acoustic pressure has that value (see figure C.1)
Symbol: t
FWHMp+
Unit: second, s
NOTE – The subscript "FWHM" stands for "full width, half maximum".
3.4
derived pulse-intensity integral
time integral of the instantaneous intensity at a particular point in a pressure pulse field over
the (see 3.31 of IEC 61102)
pressure pulse waveform
Symbol: PII
Unit: joule per metre squared, J/m
3.5
end-of-cable loaded sensitivity of a hydrophone
ratio of the voltage at the end of any integral cable or connector of a hydrophone, when
connected to a specified electrical input impedance, to the instantaneous acoustic pressure
in the undisturbed free field of a plane wave in the position of the acoustic centre of the
hydrophone if the hydrophone were removed (see 3.14 of IEC 61102)
Symbol: M
L
–1
Unit: volt per pascal, V Pa
61846 © IEC:1998(E) – 7 –
3.6
focal cross-sectional area
area of the peak-compressional acoustic pressure contour which is –6 dB relative to the
value at the focus and is in the plane, perpendicular to the beam axis, which contains the
focus
Symbol: A
f
Unit: metre squared, m
3.7
focal extent
shortest distance along the z axis that connects points on the –6 dB contour of peak-positive
acoustic pressure in the x-z plane on either side of the focus
Symbol: f
z
Unit: metre, m
3.8
focal volume
volume in space contained within the surface defined by the –6 dB (relative to the value at the
focus) peak-compressional acoustic pressure contours measured around the focus
Symbol: V
f
Unit: metre cubed, m
NOTE – It is difficult to measure –6 dB points throughout the volume around the focus. It is reasonable in practice
to approximate the focal volume from measurements taken in three orthogonal directions: the beam axis (z axis);
the direction of maximum beam diameter (x axis); the axis perpendicular to the x axis (y axis).
3.9
focal width, maximum
maximum width of the –6 dB contour of p around the focus in the x-y plane which contains
+
the focus
Symbol: f
x
Unit: metre, m
3.10
focal width, orthogonal
width of the –6 dB contour of p around the focus, in the x-y plane which contains the focus,
+
in the direction perpendicular to f
x
Symbol: f
y
Unit: metre, m
3.11
focus
location in the pressure pulse field of the maximum peak-positive acoustic pressure
3.12
hydrophone
transducer that produces electrical signals in response to waterborne acoustic signals
[IEV 801-32-26] (see also IEC 60866)

– 8 – 61846 © IEC:1998(E)
3.13
instantaneous acoustic pressure
pressure minus the ambient pressure at a particular instant
...