IEC 60601-2-37:2024

IEC 60601-2-37 ®
Edition 3.0 2024-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Medical electrical equipment –
Part 2-37: Particular requirements for the basic safety and essential performance
of ultrasonic medical diagnostic and monitoring equipment
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IEC 60601-2-37 ®
Edition 3.0 2024-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Medical electrical equipment –
Part 2-37: Particular requirements for the basic safety and essential performance
of ultrasonic medical diagnostic and monitoring equipment
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 11.040.55; 17.140.50 ISBN 978-2-8322-9372-0

– 2 – IEC 60601-2-37:2024 RLV © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
201.1 Scope, object and related standards . 8
201.2 Normative references . 10
201.3 Terms and definitions . 10
201.4 General requirements . 17
201.5 General requirements for testing ME EQUIPMENT . 18
201.6 Classification of ME EQUIPMENT and ME SYSTEMS . 18
201.7 ME EQUIPMENT identification, marking and documents . 18
201.8 Protection against electrical HAZARDS from ME EQUIPMENT . 23
201.9 Protection against MECHANICAL HAZARDS of ME EQUIPMENT and ME SYSTEMS . 23
201.10 Protection against unwanted and excessive radiation HAZARDS . 23
201.11 Protection against excessive temperatures and other HAZARDS . 24
201.12 Accuracy of controls and instruments and protection against hazardous
outputs . 30
201.13 HAZARDOUS SITUATIONS and fault conditions for ME EQUIPMENT . 32
201.14 PROGRAMMABLE ELECTRICAL MEDICAL SYSTEMS (PEMS) . 32
201.15 Construction of ME EQUIPMENT . 32
201.16 ME SYSTEMS . 32
201.17 *Electromagnetic compatibility of ME EQUIPMENT and ME SYSTEMS . 32
202 ELECTROMAGNETIC DISTURBANCES – Requirements and tests . 33
212 Requirements for medical electrical equipment and medical electrical
systems intended for use in the emergency medical services environment
(EMS) . 36
Annexes . 37
Annex AA (informative) Particular guidance and rationale . 38
Annex BB (informative) Guidance in classification according to CISPR 11 . 47
Annex CC (informative) Guidance to the MANUFACTURER on the interpretation of TI and
MI to be used to inform the OPERATOR . 48
Annex DD (informative) Example set-up to measure surface temperature of externally
applied TRANSDUCER ASSEMBLIES . 52
Annex EE (informative) Acoustic output table intended for third parties . 55
Bibliography . 58
Index of defined terms . 62

Figure AA.1 – Method a) for an external probe . 41
Figure AA.2 – Method b) for an external probe . 42
Figure AA.3 – Method b) for an external probe . 42
Figure DD.1 – Set-up of an example test object to measure the surface temperature of
externally applied transducers . 54

Table 201.101 – List of symbols . 16
Table 201.102 – Distributed essential performance requirements . 18

Table 201.103 – Acoustic output reporting table . 22
Table 201.104 – Overview of the tests noted under 201.11.1.3 . 29
Table CC.1 – Relative importance of maintaining low exposure indices in various
scanning situations . 50
Table DD.1 – Acoustic and thermal properties of tissues and materials . 52
Table DD.2 – Weight % pure components . 53
Table EE.1 – Example of acoustic output table for third parties . 56

– 4 – IEC 60601-2-37:2024 RLV © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –

Part 2-37: Particular requirements for the basic safety
and essential performance of ultrasonic medical
diagnostic and monitoring equipment

FOREWORD
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This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 60601-2-37:2007+AMD1:2015 CSV. A vertical bar
appears in the margin wherever a change has been made. Additions are in green text,
deletions are in strikethrough red text.

IEC 60601-2-37 has been prepared by subcommittee 62B: Medical imaging equipment,
software, and systems, of IEC technical committee 62: Medical equipment, software, and
systems. It is an International Standard.
This third edition cancels and replaces the second edition published in 2007 and
Amendment 1:2015. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) technical and editorial changes resulting from the amended general standard
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 and
its collateral standards IEC 60601-1-xx,
b) technical and editorial changes as a result of maintenance to normative references;
c) technical and editorial changes resulting from relevant developments in TC 87 Ultrasonics
standards. In particular, Clause 201.11 about protection against excessive temperatures
and other hazards has been fully revised.
The text of this International Standard is based on the following documents:
Draft Report on voting
62B/1318/CDV 62B/1348/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
In this document, the following print types are used:
– requirements and definitions: roman type.
– test specifications: italic type.
– informative material appearing outside of tables, such as notes, examples and references: in smaller type.
Normative text of tables is also in a smaller type.
– TERMS DEFINED IN CLAUSE 3 OF IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020, IN THIS DOCUMENT OR AS NOTED: SMALL CAPITALS.
In referring to the structure of this document, the term
– "clause" means one of the seventeen numbered divisions within the table of contents,
inclusive of all subdivisions (e.g. Clause 7 includes subclauses 7.1, 7.2, etc.);
– "subclause" means a numbered subdivision of a clause (e.g. 7.1, 7.2 and 7.2.1 are all
subclauses of Clause 7).
References to clauses within this document are preceded by the term "Clause" followed by the
clause number. References to subclauses within this document are by number only.
In this document, the conjunctive "or" is used as an "inclusive or" so a statement is true if any
combination of the conditions is true.

– 6 – IEC 60601-2-37:2024 RLV © IEC 2024
The verbal forms used in this document conform to usage described in Clause 7 of the ISO/IEC
Directives, Part 2. For the purposes of this document, the auxiliary verb:
– "shall" means that compliance with a requirement or a test is mandatory for compliance with
this document;
– "should" means that compliance with a requirement or a test is recommended but is not
mandatory for compliance with this document;
– "may" is used to describe a permissible way to achieve compliance with a requirement or
test.
An asterisk (*) as the first character of a title or at the beginning of a paragraph or table title
indicates that there is guidance or rationale related to that item in Annex AA.
A list of all parts of the IEC 60601 series, published under the general title: Medical electrical
equipment, can be found on the IEC website
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document 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.

INTRODUCTION
In this document, safety requirements additional to those in the general standard
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012, and IEC 60601-1:2005/AMD2:2020 are
specified for ULTRASONIC DIAGNOSTIC EQUIPMENT.
A general guidance and rationale for the requirements of this document are given in Annex AA.
Knowledge of the reasons for these requirements will not only facilitate the proper application
of this document but will, in due course, expedite any revision necessitated by changes in
clinical practice or as a result of developments in technology.
The approach and philosophy used in drafting this document for safety of ULTRASONIC
DIAGNOSTIC EQUIPMENT are consistent with those in standards of the IEC 60601-2 series that
apply to other diagnostic modalities, such as X-ray equipment and magnetic resonance systems.
In each case, the safety standard is intended to require increasing sophistication of output
display indicators and controls with increasing energy levels in the interrogating field of
diagnosis. Thus, for all such diagnostic modalities, it is the responsibility of the OPERATOR to
understand the risk of the output of the ULTRASONIC DIAGNOSTIC EQUIPMENT, and to act
appropriately in order to obtain the needed diagnostic information with the minimum risk to the
PATIENT.
INTRODUCTION TO AMENDMENT 1
The second edition of IEC 60601-2-37 was published in 2007. Since that publication, the parent
standard, IEC 60601-1:2005, entered maintenance, under which an amendment (IEC 60601-
1:2005/AMD1:2012) and a consolidated edition 3.1 (IEC 60601-1:2005 and IEC 60601-
1:2005/AMD1:2012) were published. This amendment to IEC 60601-2-37:2007 addresses
three issues:
1) technical changes proposed by National Committees as a result of 4 years of practical
usage,
2) technical and editorial changes resulting from the amended general standard
IEC 60601-1:2005 and IEC 60601-1:2005/AMD1:2012 and its collateral standards
IEC 60601-1-xx, and
3) technical changes as a result of maintenance to normative references.

– 8 – IEC 60601-2-37:2024 RLV © IEC 2024
MEDICAL ELECTRICAL EQUIPMENT –

Part 2-37: Particular requirements for the basic safety
and essential performance of ultrasonic medical
diagnostic and monitoring equipment

The clauses and subclauses of the general standard apply except as follows:
201.1 Scope, object and related standards
Clause 1 of the general standard IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012, and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
201.1.1 *Scope
Replacement:
This document applies to the BASIC SAFETY and ESSENTIAL PERFORMANCE of ULTRASONIC
DIAGNOSTIC EQUIPMENT as defined in 201.3.217, hereinafter referred to as ME EQUIPMENT.
If a clause or subclause is specifically intended to be applicable to ME EQUIPMENT only, or to
ME SYSTEMS only, the title and content of that clause or subclause will say so. If that is not the
ME EQUIPMENT and to ME SYSTEMS, as relevant.
case, the clause or subclause applies both to
HAZARDS inherent in the intended physiological function of ME EQUIPMENT or ME SYSTEMS within
the scope of this document are not covered by specific requirements in this document except
in 7.2.13 and 8.4.1 of this standard 201.7.2.13.
NOTE See also subclause 4.2 of this standard.
This document does not cover ultrasonic therapeutic equipment. Equipment used for the
imaging or diagnosis of body structures by ultrasound in conjunction with other medical
procedures is covered.
201.1.2 Object
Replacement:
The object of this document is to establish particular BASIC SAFETY and ESSENTIAL PERFORMANCE
requirements for ULTRASONIC DIAGNOSTIC EQUIPMENT as defined in 201.3.217.
201.1.3 Collateral standards
Addition:
This document refers to those applicable collateral standards that are listed in Clause 2 of
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 and
Clause 201.2 of this document.
IEC 60601-1-2:2014, IEC 60601-1-2:2014/AMD1:2020, IEC 60601-1-12:2014 and
IEC 60601-1-12:2014/AMD1:2020 apply as modified in Clause 202 and Clause 212 respectively.
All other published collateral standards in the IEC 60601-1 series apply as published.

201.1.4 Particular standards
Replacement:
In the IEC 60601 series, particular standards may modify, replace or delete requirements
contained in the general standard IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 as appropriate for the particular ME EQUIPMENT under
consideration, and may add other BASIC SAFETY and ESSENTIAL PERFORMANCE requirements.
A requirement of a particular standard takes priority over the general standard IEC 60601-
1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020.
For brevity, IEC 60601-1 is referred to in this particular standard as the general standard.
Collateral standards are referred to by their document number.
The numbering of sections, clauses and subclauses of this document corresponds to that of the
general standard IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-
1:2005/AMD2:2020 with the prefix "201" (e.g. 201.1 in this document addresses the content of
Clause 1 of the general standard IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020) or applicable collateral standard with the prefix "20x" where x
is the final digit(s) of the collateral standard document number (e.g. 202.6 in this document
addresses the content of Clause 6 of the IEC 60601-1-2 collateral standard, 203.4 in this
document addresses the content of Clause 4 of the IEC 60601-1-3 collateral standard, etc.).
The changes to the text of the general standard IEC 60601-1:2005, IEC 60601-
1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 are specified by the use of the following
words:
"Replacement" means that the clause or subclause of the general standard IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 or applicable collateral
standard is replaced completely by this document.
"Addition" means that the text of this document is additional to the requirements of the general
standard IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-
1:2005/AMD2:2020 or applicable collateral standard.
"Amendment" means that the clause or subclause of the general standard IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 or applicable collateral
standard is amended as indicated by the text of this document.
Subclauses, figures or tables which are additional to those of the general standard are
numbered starting from 201.101. However, due to the fact that definitions in the general
standard are numbered 3.1 through 3.154, additional definitions in this document are numbered
beginning from 201.3.201. Additional annexes are lettered AA, BB, etc., and additional items
aa), bb), etc.
Subclauses or figures which are additional to those of a collateral standard are numbered
starting from 20x, where "x" is the number of the collateral standard, e.g. 202 for IEC 60601-1-2,
203 for IEC 60601-1-3, etc.
The term "this document" is used to make reference to the general standard IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020, any applicable collateral
standards and this document taken together.
Where there is no corresponding section, clause or subclause in this document, the section,
clause or subclause of the general standard IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012
and IEC 60601-1:2005/AMD2:2020 or applicable collateral standard, although possibly not
relevant, applies without modification; where it is intended that any part of the general standard
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 or

– 10 – IEC 60601-2-37:2024 RLV © IEC 2024
applicable collateral standard, although possibly relevant, is not to be applied, a statement to
that effect is given in this document.
201.2 Normative references
Clause 2 of the general standard IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies except as follows:
Addition:
IEC 60601-1:2005, Medical electrical equipment – Part 1: General requirements for basic safety
and essential performance
IEC 60601-1:2005/AMD1:2012
IEC 60601-1:2005/AMD2:2020
IEC 60601-1-12:2014, Medical electrical equipment – Part 1-12: General requirements for basic
safety and essential performance – Collateral Standard: Requirements for medical electrical
equipment and medical electrical systems intended for use in the emergency medical services
environment
IEC 60601-1-12:2014/AMD1:2020
IEC 60601-2-18:2009, Medical electrical equipment – Part 2-18: Particular requirements for the
basic safety and essential performance of endoscopic equipment
IEC 62127-1:20072022, Ultrasonics – Hydrophones – Part 1: Measurement and
characterization of medical ultrasonic fields up to 40 MHz
IEC 62127-1:2007/AMD1:2013
IEC 62359:2010, Ultrasonics – Field characterization – Test methods for the determination of
thermal and mechanical indices related to medical diagnostic ultrasonic fields
IEC 62359:2010/AMD1:2017
CISPR 11:2024, Industrial, scientific and medical equipment – Radio-frequency disturbance
characteristics – Limits and methods of measurement
201.3 Terms and definitions
For the purposes of this document, the terms and definitions given in the general standard
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 and in
IEC 62359 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
NOTE 1 An index of defined terms is given after the Bibliography.
NOTE 2 A list of symbols used in this document is found in Table 201.101.
___________
There exists a consolidated edition (3.1) including IEC 60601-1:2005 and its Amendment 1 (2012).
There exists a consolidated edition (1.1) including IEC 62127-1:2007 and its Amendment 1 (2013).

Addition:
201.3.201
BONE THERMAL INDEX
TIB
THERMAL INDEX for applications such as foetal (second and third trimester), in which the
ultrasound beam passes through soft tissue and a focal region is in the immediate vicinity of
bone
Unit: None
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.17, modified – The definition
no longer refers to neonatal cephalic applications, and The original notes have been deleted.]
201.3.202
COMBINED-OPERATING MODE
mode of operation of ULTRASONIC DIAGNOSTIC EQUIPMENT that combines more than one DISCRETE-
OPERATING MODE
201.3.203
CRANIAL-BONE THERMAL INDEX
TIC
THERMAL INDEX for applications, in which the ultrasound beam passes through bone near the
beam entrance into the body, such as paediatric and adult cranial or neonatal cephalic
applications
Unit: None
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.21, modified – The definition
now includes a reference to neonatal cephalic applications, and The original notes have been
deleted.]
201.3.204
DEFAULT SETTING
specific state of control the ULTRASONIC DIAGNOSTIC EQUIPMENT will enter upon power-up, new
PATIENT select, or change from non-foetal to foetal applications
201.3.205
DISCRETE-OPERATING MODE
mode of operation of ULTRASONIC DIAGNOSTIC EQUIPMENT in which the purpose of the excitation
of the ULTRASONIC TRANSDUCER or ULTRASONIC TRANSDUCER element group is to utilise only one
diagnostic methodology
201.3.206
FULL SOFTWARE CONTROL OF ACOUSTIC OUTPUT
means by which the ULTRASONIC DIAGNOSTIC EQUIPMENT manages the acoustic output
independent of direct OPERATOR control
201.3.207
INVASIVE TRANSDUCER ASSEMBLY
transducer which, in whole or in part, penetrates inside the body, either through a body orifice
or through the surface of the body

– 12 – IEC 60601-2-37:2024 RLV © IEC 2024
201.3.208
MECHANICAL INDEX
the displayed parameter representing potential cavitation bioeffects
Indicator of the risk for bioeffects due to mechanical or nonthermal mechanisms, such as
cavitation
Symbol: MI
Unit: None
Note 1 to entry: See IEC 62359 for methods of determining the MECHANICAL INDEX.
201.3.209
MULTI-PURPOSE ULTRASONIC DIAGNOSTIC EQUIPMENT
ULTRASONIC DIAGNOSTIC EQUIPMENT that is intended for more than one clinical application
201.3.210
NON-SCANNING MODE
mode of operation of ULTRASONIC DIAGNOSTIC EQUIPMENT that involves a sequence of ultrasonic
pulses that give rise to ultrasonic scan lines that follow the same acoustic path
201.3.211
PRUDENT USE STATEMENT
affirmation of the principle that only necessary clinical information should be acquired and that
high exposure levels and long exposure times should be avoided
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.40, modified – The definition
has been reworded.]
201.3.212
SCANNING MODE
mode of operation of ULTRASONIC DIAGNOSTIC EQUIPMENT that involves a sequence of ultrasonic
pulses that give rise to scan lines that do not follow the same acoustic path
201.3.213
SOFT TISSUE THERMAL INDEX
TIS
THERMAL INDEX related to soft tissues
Unit: None
[SOURCE: IEC 62359:2010, 3.52, modified – The original notes have been deleted.]
201.3.214
THERMAL INDEX
TI
indicator of the risk of bioeffect due to thermal mechanisms expressed as the ratio of
ATTENUATED OUTPUT POWER at a specified point to the ATTENUATED OUTPUT POWER required to
raise the temperature at that point in a specific tissue model by 1 °C
Unit: None
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.56, modified – The term
"ATTENUATED ACOUSTIC POWER" has been replaced twice by the term "ATTENUATED OUTPUT
POWER" Addition of “indicator of the risk of bioeffect due to thermal mechanisms expressed as
the”, and the original note has been deleted.]

201.3.215
TRANSDUCER ASSEMBLY
those parts of ULTRASONIC DIAGNOSTIC EQUIPMENT comprising either the ULTRASONIC TRANSDUCER
and/or the ULTRASONIC TRANSDUCER ELEMENT GROUP, or both, together with any integral
components, such as an acoustic lens or integral stand-off
Note 1 to entry: The TRANSDUCER ASSEMBLY is usually separable from the ultrasound instrument console.
[SOURCE: IEC 62127-1:2007, 3.69 IEC 62359:2010 and IEC 62359:2010AMD1:2017, 3.57,
modified – the original term "medical diagnostic ultrasound equipment" has been replaced by
"ULTRASONIC DIAGNOSTIC EQUIPMENT" in the definition.]
201.3.216
TRANSMIT PATTERN
combination of a specific set of transducer beam-forming characteristics (determined by the
transmit aperture size, apodisation shape, and relative timing/phase delay pattern across the
aperture, resulting in a specific focal length and direction), and an electrical drive waveform of
a specific fixed shape but variable amplitude
[SOURCE: IEC 62359:2010, 3.58]
201.3.217
ULTRASONIC DIAGNOSTIC EQUIPMENT
MEDICAL ELECTRICAL EQUIPMENT that is intended for ultrasonic medical examination
201.3.218
ULTRASONIC TRANSDUCER
device capable of converting electrical energy to mechanical energy within the ultrasonic
frequency range and/or reciprocally of converting mechanical energy to electrical energy
[SOURCE: IEC 62127-1:2007/AMD1:2013, 3.73 IEC 62127-1:2022, 3.88]
201.3.219
ATTENUATED PULSE-AVERAGE INTENSITY
I
pa,α
value of the acoustic PULSE-AVERAGE INTENSITY after attenuation and at a specified point, and
given by
(−αzf /10 dB)
awf
I = I (z)10
pa,α pa
(−αzf /10dB)
awf
I zI= z 10 (1)
( ) ( )
pa,α pa
where
α is the ACOUSTIC ATTENUATION COEFFICIENT as defined in IEC 62359:2010, definition 3.1;
z is the distance from the EXTERNAL TRANSDUCER APERTURE to the point of interest;
f is the ACOUSTIC WORKING FREQUENCY as defined in IEC 62359:2010 and
awf
IEC 62359:2010/AMD1:2017, definition 3.4;
I (z) is the PULSE-AVERAGE INTENSITY measured in water as defined in IEC 62127-1:2007
pa
and IEC 62127-1:2007/AMD1:2013, definition 3.47 IEC 62127-1:2022, 3.53.
–2
Unit: W m
– 14 – IEC 60601-2-37:2024 RLV © IEC 2024
201.3.220
NUMBER OF PULSES PER ULTRASONIC SCAN LINE
n
pps
number of acoustic pulses travelling along a particular ULTRASONIC SCAN LINE
Note 1 to entry: Here ULTRASONIC SCAN LINE refers to the path of acoustic pulses on a particular BEAM AXIS in
SCANNING and NON-SCANNING MODES.
Note 2 to entry: This number can be used in the calculation of any ultrasound temporal average value from
HYDROPHONE measurements.
Note 3 to entry: The following shows an example of the NUMBER OF PULSES PER ULTRASONIC SCAN LINE and the
NUMBER OF ULTRASONIC SCAN LINES (";" indicates the end of a frame):
1 2 3 4; 1 2 3 4; 1 2 3 4… n = 1; n = 4
pps sl
1 1 2 2 3 3 4 4; 1 1 2 2 3 3 4 4; … n = 2; n = 4
pps sl
1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4; 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4; … n = 4; n = 4
pps sl
1 1 2 2 3 3 4 4 1 1 1 2 2 2 3 3 3 4 4 4; 1 1 2 2 3 3 4 4 1 1 1 2 2 2 3 3 3 4 4 4; … n = 5; n = 4 (within one frame
pps sl
the pulses down each line may not occur contiguously).
Within one frame, all scan lines may not have the same n value. An example is: 1 2 2 3 3 4; 1 2 2 3 3 4; … avg
pps
n = 1,5; max n = 2; n = 4
pps pps sl
[SOURCE: IEC 61157:2007/AMD1:2013, 3.45, modified – The fourth example in the Note 3 to
entry has been corrected.]
201.3.221
ULTRASOUND ENDOSCOPE
ENDOSCOPE with built-in ULTRASOUND TRANSDUCERS
201.3.222
ENDOSCOPE
medical instrument having viewing means, with or without optics, introduced into a body cavity
through a natural or surgically created body opening for examination, diagnosis or therapy
Note 1 to entry: ENDOSCOPES may be of rigid, flexible or capsule type, each of which may have different image
pick-up systems (e.g. via lenses or electronic/ultrasonic sensors) and different image transmission systems (e.g.
optical (via lenses or fibre bundles), or electrical/electronic).
Note 2 to entry: Note 1 to entry differs from NOTE 1 of definition 3.1 in ISO 8600-1 in order to include 'capsule'
endoscopes.
[SOURCE: IEC 60601-2-18:2009, 201.3.203]
201.3.223
DEPTH FOR PEAK PULSE-INTENSITY INTEGRAL
z
pii
position of maximum SPATIAL-PEAK TEMPORAL-AVERAGE INTENSITY for NON-SCANNING MODE
components, determined beyond the BREAK-POINT DEPTH, z , on the BEAM-AXIS
bp
depth z on the BEAM AXIS and beyond the BREAK-POINT DEPTH z from the external transducer
bp
aperture to the plane of maximum PULSE-INTENSITY INTEGRAL (pii) as approximated by the PULSE-
PRESSURE-SQUARED INTEGRAL (ppsi)
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.24, modified ─ Notes to entry
1, 2 and 3 deleted.]
201.3.224
DEPTH FOR PEAK ATTENUATED PULSE-INTENSITY INTEGRAL
z
pii, α
position of maximum ATTENUATED SPATIAL-PEAK TEMPORAL-AVERAGE INTENSITY for NON-SCANNING
MODE components, determined beyond the BREAK-POINT DEPTH, z , on the BEAM-AXIS
bp
depth z on the BEAM AXIS and beyond the BREAK-POINT DEPTH z of peak ATTENUATED PULSE-
bp
INTENSITY INTEGRAL
Unit: m
Note 1 to entry: BEAM-AXIS and BREAK-POINT DEPTH are defined in IEC 62359.
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.71, modified ─ Main term
” replaced with “depth for peak attenuated pulse-intensity integral”,
“depth for maximum
pii, α
Notes to entry 1, 2 and 3 deleted and addition of a new Note to entry. ]
201.3.225
DEPTH FOR PEAK SUM OF PULSE-INTENSITY INTEGRALS
z
sii
position of maximum SPATIAL-PEAK TEMPORAL-AVERAGE INTENSITY for SCANNING MODE
components, determined beyond THE BREAK-POINT DEPTH, z , on the BEAM-AXIS
bp
depth z on the BEAM AXIS and beyond the BREAK-POINT DEPTH z of peak SCAN-INTENSITY
bp
INTEGRAL
Unit: m
Note 1 to entry: BEAM-AXIS and BREAK-POINT DEPTH are defined in IEC 62359.
Note 2 to entry: The subscript 'sii' indicates the scan intensity integral (sii). The sii for SCANNING MODE components
at a particular point is determined from the sum over a complete scan frame of the PULSE-INTENSITY INTEGRALS of the
ULTRASONIC SCAN LINES that make up the scanning components of a combined mode. Non-scanned components are
excluded from the sum. See IEC 62359 and IEC 62127-1 for more details.
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.74, modified ─ Main term
“depth for maximum sii” replaced with “depth for peak sum of pulse-intensity integrals”, Notes
to entry 1, 2 and 3 deleted and addition of new Notes 1 and 2 to entry.]
201.3.226
DEPTH FOR PEAK SUM OF ATTENUATED PULSE-INTENSITY INTEGRALS
z
sii,α
position of maximum ATTENUATED SPATIAL-PEAK TEMPORAL-AVERAGE INTENSITY for SCANNING
MODE components, determined beyond the BREAK-POINT DEPTH, z , on THE BEAM-AXIS
bp
depth z on the BEAM AXIS and beyond the BREAK-POINT DEPTH z of peak ATTENUATED SCAN-
bp
INTENSITY INTEGRAL
Unit: m
Note 1 to entry: BEAM-AXIS and BREAK-POINT DEPTH are defined in IEC 62359.
Note 2 to entry: The subscript "sii" indicates the "scan intensity integral" that is the sum at a particular point of the
PULSE-INTENSITY INTEGRALS of the ULTRASONIC SCAN LINES comprising a SCANNING MODE component. See IEC 62359
and IEC 62127-1 for additional details.
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.75, modified ─ Main term
“depth for maximum sii ” replaced with “depth for peak sum of attenuated pulse-intensity
α
integrals”, addition of “peak” in the definition, Notes to entry 1, 2 and 3 deleted and addition of
new Notes 1 and 2 to entry.]
– 16 – IEC 60601-2-37:2024 RLV © IEC 2024
201.3.227
DEPTH FOR MECHANICAL INDEX
z
MI
depth on the BEAM-AXIS from the EXTERNAL TRANSDUCER APERTURE to the plane of maximum
ATTENUATED PULSE INTENSITY INTEGRAL (pii ) ATTENUATED PULSE-PRESSURE-SQUARED-INTEGRAL
α
(ppsi )
α
Unit: m
[SOURCE: IEC 62359:2010 and IEC 62359:2010/AMD1:2017, 3.23]
201.3.228
THERMAL OFFSET
∆T
offset
difference between a) the temperature of the APPLIED PART of the TRANSDUCER ASSEMBLY at
steady-state in the measurement setting before transmitting begins and b) the steady-state
temperature at the same location in the measurement setting when the TRANSDUCER ASSEMBLY
was not present
Note 1 to entry: The value of the THERMAL OFFSET can be positive, negative or zero.
201.3.229
ULTRASOUND
acoustic oscillation whose frequency is above the high-frequency limit of audible sound (about
20 kHz)
[SOURCE: IEC 60050-802:2011, 802-01-01]
Table 201.101 – List of symbols
Symbol Term Reference
A = –12 dB OUTPUT BEAM AREA IEC 62359
aprt
d = EQUIVALENT BEAM DIAMETER IEC 62359
eq
f = ACOUSTIC WORKING FREQUENCY IEC 62359
awf
I = ATTENUATED PULSE-AVERAGE INTENSITY
pa,α
pii = PULSE-INTENSITY INTEGRAL IEC 62359
pii = ATTENUATED PULSE-INTENSITY INTEGRAL IEC 62359
α
I = ATTENUATED SPATIAL-PEAK PULSE-AVERAGE INTENSITY IEC 62359
sppa,α
I = SPATIAL-PEAK TEMPORAL-AVERAGE INTENSITY IEC 62359
spta
I = ATTENUATED SPATIAL-PEAK TEMPORAL-AVERAGE INTENSITY IEC 62359
spta,α
I (z) = ATTENUATED TEMPORAL-AVERAGE INTENSITY IEC 62359
ta,α
MI = MECHANICAL INDEX IEC 62359
n = NUMBER OF PULSES PER ULTRASONIC SCAN LINE IEC 61157
pps
P = OUTPUT POWER IEC 62359
P = BOUNDED-SQUARE OUTPUT POWER IEC 62359
1x1
P = ATTENUATED OUTPUT POWER IEC 62359
α
p = ATTENUATED PEAK-RAREFACTIONAL ACOUSTIC PRESSURE IEC 62359
r,α
p = PEAK-RAREFACTIONAL ACOUSTIC PRESSURE IEC 62359
r
prr = PULSE REPETITION RATE IEC 62359

Symbol Term Reference
srr = SCAN REPETITION RATE IEC 62127-1
TI = THERMAL INDEX IEC 62359
TIB = BONE THERMAL INDEX IEC 62359
TIC = CRANIAL-BONE THERMAL INDEX IEC 62359
TIS = SOFT-TISSUE THERMAL INDEX IEC 62359
t = PULSE DURATION IEC 62359
d
X,Y = –12 dB OUTPUT BEAM DIMENSIONS IEC 62359
z = DEPTH FOR BONE THERMAL INDEX IEC 62359
b
z = BREAK-POINT DEPTH IEC 62359
bp
z = DEPTH FOR PEAK PULSE-INTENSITY INTEGRAL IEC 62359
pii
z = DEPTH FOR MECHANICAL INDEX IEC 62359
MI
z = DEPTH FOR PEAK ATTENUATED PULSE INTENSITY INTEGRAL IEC 62359
pii,α
z = DEPTH FOR PEAK SUM OF PULSE INTENSITY INTEGRALS IEC 62359
sii
z = DEPTH FOR PEAK SUM OF ATTENUATED PULSE INTENSITY INTEGRALS IEC 62359
sii,α
z = DEPTH FOR TIS IEC 62359
s
= THERMAL OFFSET
∆T
offset
∆T = temperature rise caused by the TRANSDUCER ASSEMBLY transmitting
tx
201.4 General requirements
Clause 4 of the general standard IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
201.4.1 Conditions for application to ME EQUIPMENT or ME SYSTEMS
Addition:
An ULTRASOUND ENDOSCOPE where the imaging means is limited to ultrasound shall be
considered an ULTRASOUND TRANSDUCER and shall meet the requirements of this document.
NOTE 1 Examples of such ULTRASOUND TRANSDUCERS include transvaginal, transesophageal (TEE), rectal,
laparoscopic and other similar intra-cavity probes.
An ULTRASOUND ENDOSCOPE having imaging means in addition to ultrasound shall also meet the
requirements of 201.11.6.5 of IEC 60601-2-18:2009.
NOTE 2 Examples of such additional imaging means include optical and CCD.
201.4.3 ESSENTIAL PERFORMANCE
Additional subclause:
201.4.3.101 Additional ESSENTIAL PERFORMANCE requirements
Table 201.102 lists the potential sources of unacceptable risk identified to characterize the
ESSENTIAL PERFORMANCE of ULTRASONIC DIAGNOSTIC EQUIPMENT and the subclauses in which the
requirements are found.
– 18 – IEC 60601-2-37:2024 RLV © IEC 2024
Table 201.102 – Distributed essential performance requirements
Requirement Subclause
Free from noise on a waveform or artefacts or distortion in an image or error of a
displayed numerical value which cannot be attributed to a physiological effect and which 202.6.2.1.10202.8.1
may can alter the diagnosis.
Free from the display of incorrect numerical values associated with the diagnosis to be
202.6.2.1.10202.8.1
a
performed .
201.12.4.2
a
Free from the display of incorrect safety-related indications.
202.6.2.1.10202.8.1
201.10.101
Free from the production of unintended or excessive ultrasound output.
202.6.2.1.10202.8.1
Free from the production of unintended or excessive TRANSDUCER ASSEMBLY surface
202.6.2.1.10202.8.1
temperature.
Free from the production of unintended or uncontrolled motion of TRANSDUCER
202.6.2.1.10202.8.1
ASSEMBLIES intended for intra-corporeal use.
a
"incorrect" in the sense that the displayed value differs from what is calculated (having been altered during
data transfer), or the calculation itself is not correct.

NOTE In some circumstances the need f
...