SIST EN 62359:2011/A1:2018

SLOVENSKI STANDARD
01-april-2018
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Ultrasonics - Field characterization - Test methods for the determination of thermal and
mechanical indices related to medical diagnostic ultrasonic fields
Ultraschall - Charakterisierung von Feldern - Prüfverfahren für die Ermittlung des
thermischen und des mechanischen Indexes bezogen auf medizinische
Ultraschalldiagnostikfelder
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Ta slovenski standard je istoveten z: EN 62359:2011/A1:2018
ICS:
11.040.55 'LDJQRVWLþQDRSUHPD Diagnostic equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 62359:2011/A1

NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2018
ICS 17.140.50
English Version
Ultrasonics - Field characterization - Test methods for the
determination of thermal and mechanical indices related to
medical diagnostic ultrasonic fields
(IEC 62359:2010/A1:2017)
Ultrasons - Caractérisation du champ - Méthodes d'essai Ultraschall - Charakterisierung von Feldern - Prüfverfahren
pour la détermination d'indices thermique et mécanique des für die Ermittlung des thermischen und des mechanischen
champs d'ultrasons utilisés pour le diagnostic médical Indexes bezogen auf medizinische
(IEC 62359:2010/A1:2017) Ultraschalldiagnostikfelder
(IEC 62359:2010/A1:2017)
This amendment A1 modifies the European Standard EN 62359:2011; it was approved by CENELEC on 2017-11-03. CENELEC members
are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this amendment the status of a
national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This amendment exists in three official versions (English, French, German). A version in any other language made by translation under the
responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as
the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 62359:2011/A1:2018 E

European foreword
The text of document 87/661/FDIS, future edition 1 of IEC 62359:2010/A1:2017, prepared by IEC/TC
87 "Ultrasonics" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:

• latest date by which this document has (dop) 2018-08-03
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2020-11-03
standards conflicting with this
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice
The text of the International Standard IEC 62359:2010/A1:2017 was approved by CENELEC as a
European Standard without any modification.
Replace the Annex ZA by the following:

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
P ublication Year Title EN/HD Year
IEC 60601-2-37 2007 Medical electrical equipment -- Part 2-37: EN 60601-2-37 2008
Particular requirements for the basic safety
and essential performance of ultrasonic
medical diagnostic and monitoring
equipment
- -  + A11 2011
+ A1 2015  + A1 2015
IEC 61157 2007 Standard means for the reporting of the EN 61157 2007
acoustic output of medical diagnostic
ultrasonic equipment
+ A1 2013  + A1 2013
IEC 61161 2013 Ultrasonics - Power measurement - EN 61161 2013
Radiation force balances and performance
requirements
IEC 61828 2001 Ultrasonics - Focusing transducers - EN 61828 2001
Definitions and measurement methods for
the transmitted fields
IEC 62127-1 2007 Ultrasonics - Hydrophones -- Part 1: EN 62127-1 2007
Measurement and characterization of
medical ultrasonic fields up to 40 MHz
+ A1 2013  + A1 2013
IEC 62127-2 2007 Ultrasonics - Hydrophones -- Part 2: EN 62127-2 2007
Calibration for ultrasonic fields up to 40 MHz
IEC 62127-3 2007 Ultrasonics - Hydrophones -- Part 3: EN 62127-3 2007
Properties of hydrophones for ultrasonic
fields up to 40 MHz
IEC 62359 ®
Edition 2.0 2017-09
INTERNATIONAL
STANDARD
AMENDMENT 1
Ultrasonics – Field characterization –

Test methods for the determination of thermal and mechanical indices related

to medical diagnostic ultrasonic fields

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.140.50 ISBN 978-2-8322-4821-8

– 2 – IEC 62359:2010/AMD1:2017
© IEC 2017
FOREWORD
This amendment has been prepared by IEC technical committee 87: Ultrasonics.
The text of this amendment is based on the following documents:
FDIS Report on voting
87/661/FDIS 87/665/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC website 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.

_____________
Introduction to Amendment
The second edition of IEC 62359 was published in 2010. Since then,
IEC 60601-2-37:2007/AMD1:2015 has been published and calls for provision of attenuated
spatial peak temporal average intensity, I , and attenuated spatial peak pulse
spta,a
average intensity, I , at specific spatial maximum points in the ultrasonic field on the
sppa,a
beam axis. No IEC standard describes the determination of these quantities at these specific
positions. IEC 62359 for determining the thermal indices currently uses similar values at other
positions, therefore, the determination of attenuated spatial peak temporal average
, and attenuated spatial peak pulse average intensity, I , has been
intensity, I
spta,a sppa,a
added as an annex in this amendment.
Additionally, references to newly published collateral standards have been updated.
_____________
IEC 62359:2010/AMD1:2017 – 3 –
© IEC 2017
2 Normative references
Replace the first reference by the following:
IEC 60601-2-37:2007, Medical electrical equipment – Part 2-37: Particular requirements for
the basic safety and essential performance of ultrasonic medical diagnostic and monitoring
equipment
IEC 60601-2-37:2007/AMD1:2015
Replace the second reference by the following:
IEC 61157:2007, Standard means for the reporting of the acoustic output of medical
diagnostic ultrasonic equipment
IEC 61157:2007/AMD1:2013
Replace, in the third reference, "IEC 61161:2006" by "IEC 61161:2013".
Replace the fifth reference by the following:
IEC 62127-1:2007, Ultrasonics – Hydrophones – Part 1: Measurement and characterization of
medical ultrasonic fields up to 40 MHz
IEC 62127-1:2007/AMD1:2013
3 Terms and definitions
Replace the first existing paragraph by the following new paragraph:
For the purposes of this document, the terms and definitions given in IEC 60601-2-37,
IEC 62127-1, IEC 62127-2, IEC 62127-3, IEC 61157 and IEC 61161 apply. Several of these
are repeated below for convenience and others are listed because they have been modified
for application to this standard.
3.3
acoustic repetition period
Replace the existing definition by the following new definition:
time interval between corresponding points of consecutive cycles, pulses or scans, depending
on the current operating mode
Add the following new NOTES 2 and 3:
NOTE 2 For continuous wave modes, the acoustic repetition period is the time interval between corresponding
points of consecutive cycles
NOTE 3 For combined operating modes where transmit pulsing of the constituent modes may be interrupted,
the arp determination should take into account non-pulsing time to calculate an average period.
Replace "NOTE 2" by NOTE 4".
3.4
acoustic working frequency
Replace, in the existing definition, the words "at the position corresponding to the spatial-
peak temporal-peak acoustic pressure" by "on the beam axis, beyond the break-point
depth, corresponding to depth of maximum pulse-intensity integral z ."
pii
Replace, in existing NOTE 2, the words "at the position of maximum pulse-pressure-squared
integral" by "at the depth for peak pulse-intensity integral".

– 4 – IEC 62359:2010/AMD1:2017
© IEC 2017
3.7
attenuated peak-rarefactional acoustic pressure
Replace, in the existing definition, the words "at a specified distance from" by "on a plane
perpendicular to the beam axis at a specified distance z from".
Replace, in the definition list after Equation (2), the words "z is the distance from the external
transducer aperture to the point of interest" by "z is the distance from the external
transducer aperture along the beam axis to the plane containing the point of interest".
3.8
attenuated pulse-intensity integral
Replace, in the definition, the words "at a specified distance from" by "on a plane
perpendicular to the beam axis at a specified distance z from".
Replace, in the definition list after Equation (3), the words "z is the distance from the external
transducer aperture to the point of interest" by "z is the distance from the external
transducer aperture along the beam axis to the plane containing the point of interest".
Replace "NOTE" by "NOTE 1".
Add new NOTE 2:
NOTE 2 For measurement purposes of this standard, pii is equivalent to 1/(ρc) times the attenuated pulse-
α
pressure-squared integral at depth z, with ρc denoting the characteristic acoustic impedance of pure water.
3.9
attenuated spatial-average temporal-average intensity
Replace, in the definition, the words "at a specified distance from" by "on a plane
perpendicular to the beam axis at a specified distance z from".
Replace, in the definition list after Equation (4), the words "z is the distance from the external
transducer aperture to the point of interest" by "z is the distance from the external
transducer aperture along the beam axis to the plane containing the point of interest".
3.10
attenuated spatial-peak temporal-average intensity
Replace, in the definition, the words "at a specified distance from" by "on a plane
perpendicular to the beam axis at a specified distance z from".
Replace, in the definition list after Equation (5), the words "z is the distance from the external
transducer aperture to the point of interest" by "z is the distance from the external
transducer aperture along the beam axis to the plane containing the point of interest".
3.11
attenuated temporal-average intensity
Replace, in the definition, the words "at a specified distance from" by "on a plane
perpendicular to the beam axis at a specified distance z from".
Replace, in the definition list after Equation (6), the words "z is the distance from the external
is the distance from the external
transducer aperture to the point of interest" by "z
transducer aperture along the beam axis to the plane containing the point of interest".
3.13
beam-axis
Replace the term "beam-axis" by "beam axis".

IEC 62359:2010/AMD1:2017 – 5 –
© IEC 2017
3.17
bone thermal index
Delete, in the definition, "or neonatal cephalic (through the fontanelle)".
3.19
break-point depth
Add, after the existing definition, the words "acoustic working frequency and intensity
parameters (such as attenuated spatial-peak temporal-average intensity)"
Add, after "where D is the equivalent aperture diameter" the words "for non-scanning
eq
modes".
Replace the existing NOTE 2 by the following new note:
NOTE 2 For scanning modes, use the non-scanning mode D value calculation [Equation (8)]. Do this using
eq
the output beam area of one ultrasonic scan line; the central scan line, corresponding to the beam axis (i.e. the
line where pii MI, and f are measured).

,
awf
3.21
cranial-bone thermal index
Replace the existing definition by the following new definition:
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
3.22
default setting
Replace, in the definition, "ultrasonic diagnostic equipment" by "medical diagnostic
ultrasonic equipment".
3.23
depth for mechanical index
Replace, in the definition, the words "to the plane of maximum attenuated pulse-intensity
integral (pii )" by "to the plane of maximum attenuated pulse-pressure-squared-integral
a
(ppsi )".
a
Add new NOTE 1:
NOTE 1 Because z may occur closer to the transducer than the break-point depth z , use of ppsi rather than
MI bp α
pii is technically more appropriate. If z is larger than z , then z and z are equal.

α ppsi,α bp ppsi,α pii,α
Replace "NOTE" by "NOTE 2".
3.24
depth for peak pulse-intensity integral
Replace the existing term, definition and note by the following new term, definition and notes:
3.24
depth for maximum pulse intensity integral
depth z on the beam axis and beyond the break-point depth z from the external
bp
transduscer aperture to the plane of maximum pulse-intensity integral (pii) as
approximated by the pulse-pressure-squared integral (ppsi)
NOTE 1 Depth for maximum pii is expressed in metres (m).
NOTE 2 Depth for maximum pii is termed "depth for peak pulse-intensity integral" in
IEC 60601-2-37:2007/AMD1:2015.

– 6 – IEC 62359:2010/AMD1:2017
© IEC 2017
NOTE 3 At this depth the acoustic working frequency is determined.
3.27
Discrete-perating mode
Replace the term "Discrete-perating mode" by "discrete-operating mode".
Replace, in the definition, "ultrasonic diagnostic equipment" by "medical diagnostic
ultrasonic equipment".
3.28
equivalent aperture diameter
Replace the existing definition and equation by the following new definition and equation:
diameter of a circle the area A of which is the –12 dB output beam area A for non-
ob
scanning modes and the –12 dB scanned aperture area A for scanning modes, given by
sa
D = A
(8)
eq
π
Replace the existing NOTE 1 by the following new note:
NOTE 1 Equation (8) is used in the calculation of the cranial-bone thermal index; for non-scanning modes with
A = A and for scanning modes with A = A .
ob sa
Add new NOTE 2:
NOTE 2 Equation (8) with A = A is also used in calculating the break-point depth.
ob
Replace "NOTE 2" by "NOTE 3".
3.33
medical diagnostic ultrasonic equipment
Replace "NOTE" by "NOTE 1".
Add new NOTE 2:
NOTE 2 IEC 60601-2-37:2007 uses the term "ultrasonic diagnostic equipment" instead of medical diagnostic
ultrasonic equipment.
3.34
non-scanning mode
Replace, in the definition, the words "ultrasonic diagnostic equipment" by "medical
diagnostic ultrasonic equipment".
3.37
output power
Replace, in the source, "IEC 61161:2006" by "IEC 61161:2013".
3.40
prudent-use statements
Replace the existing definition by the following new definition:
affirmations of the principle that only necessary clinical information should be acquired and
that high exposure levels and long exposure times should be avoided

IEC 62359:2010/AMD1:2017 – 7 –
© IEC 2017
3.44
pulse repetition period
Add new NOTE 1:
NOTE 1 In general, for non-scanning modes the pulse repetition period needs to be adjusted to represent a
‘per-second’ average taking into account interruptions-in, or non-constant, pulsing; e.g. such as may occur in
combined operating modes.
Replace "NOTE" by "NOTE 2".
3.49
scanning mode
Replace, in the definition, the words "an ultrasonic diagnostic equipment" by "a medical
diagnostic ultrasonic equipment".
3.54
spatial-peak temporal-average intensity
Replace the existing NOTE 1 by the following new note:
NOTE 1 For systems in combined-operating modes, the averaging time period needs to be sufficient to include
periods in which scanning or pulsing is interrupted.
3.56
thermal index
Replace, in the definition, the two occurrences of the words " attenuated acoustic power" by
"attenuated output power"
Add the following new definitions:
3.61
instantaneous acoustic pressure
p(t)
pressure minus the ambient pressure at a particular instant in time and at a particular point in
an acoustic field
NOTE Instantaneous acoustic pressure is expressed in pascals (Pa).
[SOURCE: IEC 62127-1:2007, 3.33, modified – The reference to IEV 801-01-19 has been
removed in the definition]
3.62
attenuated instantaneous acoustic pressure
(z,t)
p
α
value of the instantaneous acoustic pressure at time t after attenuation on a plane
perpendicular to the beam axis at a specified distance z from the source, and given by
(−a z f 20 dB)
awf
p (z,t)= p(z,t)10 (26)
a
where
a is the acoustic attenuation coefficient;
z is the distance from the source to the point (plane) of interest;
f is the acoustic working frequency;
awf
p(z,t) is the instantaneous acoustic pressure
NOTE Attenuated instantaneous acoustic pressure is expressed in pascals (Pa).

– 8 – IEC 62359:2010/AMD1:2017
© IEC 2017
3.63
attenuated pulse-pressure-squared integral
ppsi (z)
α
time integral of the square of the attenuated instantaneous acoustic pressure, integrated
over the acoustic pulse waveform, on a plane perpendicular to the beam axis at a specified
distance z in an acoustic field
2 (−a z f 20 dB) (−a z f 10 dB)
awf awf
ppsi (z)= p (z,t)dt= [p(z,t)10 ] dt= ppsi(z)×10
a a (27)
∫ ∫
where
p(z,t) is the instantaneous acoustic pressure at depth z.
a is the acoustic attenuation coefficient;
z is the distance from the source to the point (plane) of interest;
f is the acoustic working frequency;
awf
ppsi is the pulse-pressure-squared integral
NOTE 1 Attenuated pulse-pressure-squared integral is expressed in pascal squared seconds (Pa s).
NOTE 2 See definition 3.43 for the non-attenuated version; with the addition here of the perpendicular plane at
depth z.
3.64
attenuated scan intensity integral
sii (z)
α
sum of the attenuated pulse intensity integrals in one scan (one frame of ultrasonic scan
lines) at depth z
–2
NOTE 1 Attenuated scan intensity integral is expressed in joules per square metre (Jm ).
NOTE 2 For measurement purposes of this standard, sii (z) is equivalent to 1/(ρc) times the sum of attenuated
α
pulse-pressure-squared integrals at depth z, for z ≥ z , with ρc denoting the characteristic acoustic impedance of
bp
pure water.
NOTE 3 See definition 3.79 for the non-attenuated version.
3.65
attenuated spatial-peak pulse-average intensity
I (z)
sppa,α
maximum value of the spatial-peak pulse-average intensity after attenuation, on a plane
perpendicular to the beam axis at a specified distance z from the source, and given by
I (z)= pii (z)
sppa,a a (28)
t (z)
d
where
t (z) is the pulse duration at the same depth z;
d
pii (z) is the attenuated pulse-intensity integral at depth z
α
–2
NOTE 1 Attenuated spatial-peak pulse-average intensity is expressed in watts per square metre (Wm ).
NOTE 2 For measurement purposes of this standard, pii (z) is equivalent to 1/(ρc) times the attenuated pulse-
α
pressure-squared integrals at depth z, ppsi (z), for z ≥ z , with ρc denoting the characteristic acoustic impedance
α bp
of pure water.
NOTE 3 See definition 3.81 for the non-attenuated version.

IEC 62359:2010/AMD1:2017 – 9 –
© IEC 2017
3.66
attenuated sum of pulse-pressure-squared integrals
s ppsi (z)
α
attenuated value of the sum of pulse-pressure-squared integrals in one scan (one frame of
ultrasonic scan lines) at depth z
NOTE 1 Attenuated sum of pulse-pressure-squared integrals is expressed in pascal squared seconds (Pa s).
NOTE 2 The attenuated sum of pulse-pressure-squared integrals at depth z will be equal to the sum of
attenuated pulse-pressure-squared integrals if each ultrasonic scan line in the frame which is included in the
sum has the same acoustic working frequency.
NOTE 3 See F.3.1.4.2 for additional explanation.
NOTE 4 See definition 3.83 for the non-attenuated version.
3.67
depth for maximum I
sppa
z
sppa,max
depth z on the beam axis and beyond the break-point depth z of maximum spatial-peak
bp
pulse-average intensity
NOTE 1 Depth for maximum I is expressed in metres (m).
sppa
NOTE 2 This depth is equivalent to the depth for maximum pii.
3.68
depth for maximum I
sppa,α
z
sppa,α,max
depth z on the beam axis and beyond the break-point depth z of maximum attenuated
bp
spatial-peak pulse-average intensity
NOTE 1 Depth for maximum I is expressed in metres (m).
sppa,α
NOTE 2 This depth is equivalent to the depth for maximum pii .
α
3.69
depth for maximum I
spta
z
spta,max
depth z on the beam axis and beyond the break-point depth z of maximum spatial-peak
bp
temporal-average intensity
NOTE 1 Depth for maximum I is expressed in metres (m).
spta
NOTE 2 For non-scanning modes, this depth is equivalent to the depth for maximum pii. For scanning modes,
it is equivalent to the depth for maximum sii.
3.70
depth for maximum I
spta,α
z
spta,α,max
depth z on the beam axis and beyond the break-point depth z of maximum attenuated
bp
spatial-peak temporal-average intensity
NOTE 1 Depth for maximum I is expressed in metres (m).
spta,α
NOTE 2 For non-scanning modes, this depth is equivalent to the depth for maximum pii . For scanning modes,
α
it is equivalent to the depth for maximum sii .
α
3.71
depth for maximum pii
α
z
pii,α
depth z on the beam axis and beyond the break-point depth z of maximum attenuated
bp
pulse-intensity integral
– 10 – IEC 62359:2010/AMD1:2017
© IEC 2017
NOTE 1 Depth for maximum pii is expressed in metres (m).

α
NOTE 2 This depth is equivalent to the depth for maximum ppsi , z , when z occurs beyond the break-
α ppsi,α ppsi,α
point depth (see 3.73).
NOTE 3 Depth for maximum pii is termed "depth for peak attenuated pulse-intensity integral" in
α
IEC 60601-2-37:2007+IEC 60601-2-37:2007/AMD1:2015.
3.72
depth for maximum ppsi
z
ppsi
depth z on the beam axis of maximum pulse-pressure-squared integral
NOTE 1 Depth for maximum ppsi is expressed in metres (m).
NOTE 2 When it occurs beyond the break-point depth, this depth is equivalent to the depth for maximum pii,
(see 3.24).
z
pii
3.73
depth for maximum ppsi
α
z
ppsi,α
depth z on the beam axis of maximum attenuated pulse-pressure-squared integral
NOTE 1 Depth for maximum ppsi is expressed in metres (m).
α
NOTE 2 When it occurs beyond the break-point depth, this depth is equivalent to the depth for maximum pii ,
α
z (i.e. depth for maximum attenuated pulse-intensity integral).
pii,α
NOTE 3 This depth is the depth for mechanical index, z (see 3.23).
MI
3.74
sii
depth for maximum
z
sii
depth z on the beam axis and beyond the break-point depth z of maximum scan-intensity
bp
integral
NOTE 1 Depth for maximum sii is expressed in metres (m).
NOTE 2 This depth is equivalent to the depth for maximum sppsi, z , when z occurs beyond the break-
sppsi sppsi
point depth (see 3.76).
NOTE 3 Depth for maximum sii is termed "depth for peak sum of pulse-intensity integrals" in
IEC 60601-2-37:2007+IEC 60601-2-37:2007/AMD1:2015.
3.75
depth for maximum sii
α
z
sii,α
depth z on the beam axis and beyond the break-point depth z of maximum attenuated
bp
scan-intensity integral
NOTE 1 Depth for maximum sii is expressed in metres (m).
α
NOTE 2 This depth is equivalent to the depth for maximum sppsi , z , when z occurs beyond the
α sppsi,α sppsi,α
break-point depth (see 3.77).
NOTE 3 Depth for maximum sii is termed "depth for peak sum of attenuated pulse-intensity integrals" in
α
IEC 60601-2-37:2007+IEC 60601-2-37:2007/AMD1:2015.
3.76
depth for maximum sppsi
z
sppsi
depth z on the beam axis of maximum sum of pulse-pressure-squared integrals
NOTE 1 Depth for maximum sppsi is expressed in metres (m).

IEC 62359:2010/AMD1:2017 – 11 –
© IEC 2017
NOTE 2 When it occurs beyond the break-point depth, this depth is equivalent to the depth for maximum sii, z
sii
(see 3.74).
NOTE 3 Depth for maximum sppsi is termed "depth for peak sum of pulse-intensity integrals" in
IEC 60601-2-37:2007+IEC 60601-2-37:2007/AMD1:2015.
3.77
depth for maximum sppsi
α
z
sppsi,α
depth z on the beam axis of maximum sum of attenuated pulse-pressure-squared
integrals
NOTE 1 Depth for maximum sppsi is expressed in metres (m).
α
NOTE 2 When it occurs beyond the break-point depth, this depth is equivalent to the depth for maximum sii ,
α
z (see 3.75).
sii,α
NOTE 3 Depth for maximum sppsi is termed "depth for peak sum of attenuated pulse-intensity integrals" in
α
IEC 60601-2-37:2007+IEC 60601-2-37:2007/AMD1:2015.
3.78
pulse-average intensity
I
pa
quotient of the pulse-intensity integral to the pulse duration at a particular point in an
acoustic field
NOTE 1 This definition applies to pulses and bursts.
–2
NOTE 2 Pulse-average intensity is expressed in watts per square metre (Wm ).
[IEC 62127-1:2007+IEC 62127-1:2007/AMD1:2013, 3.47]
3.79
scan intensity integral
sii
sum of the pulse intensity integrals in one scan (one frame of ultrasonic scan lines) at
depth z in the acoustic field
–2
NOTE 1 Scan intensity integral is expressed in joules per square metre (Jm ).
NOTE 2 For measurement purposes of this standard, sii is equivalent to 1/(ρc) times the sum of pulse-pressure-
squared integral at depth z where ρc is the characteristic acoustic impedance of pure water.
3.80
scan repetition rate
srr
inverse of the scan repetition period (see 3.50)
NOTE Scan repetition rate is expressed in hertz (Hz).
3.81
spatial-peak pulse-average intensity
I (z)
sppa
maximum value of the pulse-average intensity on a plane perpendicular to the beam axis at
a specified distance z from the source, and given by

I (z)= pii(z)
sppa (29)
t (z)
d
where
t (z) is the pulse duration at the same depth z;
d
pii(z) is the pulse-intensity integral at depth z

– 12 – IEC 62359:2010/AMD1:2017
© IEC 2017
–2
NOTE 1 Spatial-peak pulse-average intensity is expressed in watts per square metre (Wm ).
NOTE 2 For measurement purposes of this standard, pii(z) is equivalent to 1/(ρc) times the pulse-pressure-
squared integral at depth z, ppsi(z), for z ≥ z , with ρc denoting the characteristic acoustic impedance of pure
bp
water.
NOTE 3 See IEC 62127-1:2007, 3.60, which has been modified to specify the perpendicular plane at depth z.
Equation (29) and Note 2 have been added, in accordance with IEC 62127-1:2007, Equation (15).
3.82
sum of attenuated pulse-pressure-squared integrals
sppsi (z)
α
sum of the attenuated pulse-pressure-squared integrals in one scan (one frame of
ultrasonic scan lines) at depth z
NOTE 1 Sum of attenuated pulse-pressure-squared integrals is expressed in pascal squared seconds (Pa s).
NOTE 2 Closely related to the attenuated scan intensity integral, see 3.64.
NOTE 3 The sum of attenuated pulse-pressure-squared integrals at depth z will be equal to the attenuated
sum of pulse-pressure-squared integrals at depth z if each ultrasonic scan line in the frame which is included
in the sum has the same acoustic working frequency.
3.83
sum of pulse-pressure-squared integrals
sppsi(z)
sum of pulse-pressure-squared integrals in one scan (one frame of ultrasonic scan lines)
at depth z
NOTE 1 Sum of pulse-pressure-squared integrals is expressed in pascal squared seconds (Pa s).
NOTE 2 The sppsi at depth z may also be referred to as the scan pulse pressure squared integral and is
proportional to the scan intensity integral for z ≥ z .
bp
4 List of symbols
Replace the symbols "TIB " and "TIB " by "TIC " and "TIC ".
as,sc as,ns sc ns
Replace "depth for peak pulse-intensity integral" by "depth for maximum pii".

IEC 62359:2010/AMD1:2017 – 13 –
© IEC 2017
Add the following new symbols:
I spatial-peak pulse-average intensity
sppa
attenuated spatial-peak pulse-average intensity
I
sppa,α
temporal-average intensity
I
ta
attenuated pulse-pressure-squared integral
ppsi
α
scan intensity integral
sii
attenuated scan intensity integral
sii
α
sum of pulse-pressure-squared integrals
sppsi
attenuated sum of pulse-pressure-squared integrals
s ppsi
α
sum of attenuated pulse-pressure-squared integrals
sppsi
α
scan repetition rate
srr
z depth for maximum pii
pii,α α
z depth for maximum ppsi
ppsi
z depth for maximum ppsi
ppsi,α α
z depth for maximum sii
sii
z depth for maximum sii
sii,α α
z depth for maximum I
sppa,max sppa
z depth for maximum I
sppa,α,max sppa,α
z depth for maximum I
spta,max spta
z depth for maximum I ,
spta,α,max sptaα
z depth for maximum sppsi
sppsi
z depth for maximum sppsi
sppsi,α α
5.1 General
Replace, in the first and second paragraphs, the words "ultrasonic diagnostic equipment"
by "medical diagnostic ultrasonic equipment".
5.4.2.1 Determination of bone thermal index at surface for non-scanning modes,
TIC (= TIB )
ns as,ns
Delete, in the subclause's title, "(= TIB )".
as,ns
Replace the existing Equation (17) by the following new equation:
P / D
eq
TIC =
ns (17)
C
TIC
Replace, in the definition list below Equation (17), the words "is the equivalent aperture
diameter" by "is the equivalent aperture diameter; calculation for non-scanning modes as
described in 3.28 using the output beam area A ".
ob
Replace the existing note by the following new note:
NOTE TIC applies to the bone-at-surface case for non-scanning modes.
ns
– 14 – IEC 62359:2010/AMD1:2017
© IEC 2017
5.5.2.1 Determination of bone thermal index at surface for scanning modes,
TIC (= TIB )
sc as,sc
Delete, in the subclause's title, "(= TIB )".
as,sc
Add, at the end of the first sentence of the first paragraph, the words "A as described in
sa
3.28."
Replace the existing Equation (24) by the following new equation:
P / D
eq
TIC =
sc (24)
C
TIC
Replace, in the definition list below Equation (24), the words "is the equivalent aperture
diameter" by "is the equivalent aperture diameter; calculation for scanning modes as
described in 3.28 using the scanned aperture area A ".
sa
Replace the existing note by the following new note:
NOTE TIC applies to the bone-at-surface case for scanning modes.
sc
Table 1 – Summary of combination formulae for each of the THERMAL INDEX categories
Replace, in the equation in the first row, "TIC " by "TIC " and "TIC " by "TIC ".

as,ns ns as,sc sc
Table 2 – Summary of the acoustic quantities required for the determination of the
indices
Delete, in the last column of the top row, "(TIB )".
as
A.3.1 Rationale
Replace, in the second paragraph, the three occurrences of the words "ultrasonic diagnostic
equipment" by "medical diagnostic ultrasonic equipment".
A.4.1.3 Rationale for choosing a break-point depth (z )
bp
Replace, in the first sentence of the existing Note 1, the words "acoustic power" by "acoustic
output power".
A.4.1.5 Rationale for at surface TI in non-scanning mode and scanning mode
Replace the existing text of A.4.1.5 by the following new text:
Implementation of the soft tissue thermal index (TIS) assumes a homogenous tissue-path
model. One basic equation covers all cases for the at-surface case, scanning modes (such
as colour-flow mapping and B-mode) and non-scanning modes (such as Doppler and M-
mode).
In this document, the at-surface TIS-equations for all modes (scanning and non-scanning)
use P and the at-surface TIS is calculated for all aperture sizes. See A.4.1.4 for the
1x1
rationale for using the attenuated bounded-square output power in the numerator of the
thermal index equations.
There is an expectation that scanning mode and non-scanning mode TI values should
converge smoothly as the number of scan lines narrows to 1 (non-scanned), and as the depth
of interest moves from below the surface (z > 0) to the surface (z = 0).

IEC 62359:2010/AMD1:2017 – 15 –
© IEC 2017
For the at-surface TIS equation, is the bounded-square output power and
P (z) P
1x1,a 1x1
equation A results (see Table A.2).
The TIB (bone below-surface) and TIC (bone at surface) equations are fundamentally the
same. For TIC, the non-attenuated power is used, since it is an at-surface estimate. These
approximations are discussed in A.4.3 (see Table A.2).
If the dimensions of the active aperture are larger than 1 cm × 1 cm, then the thermal
perfusion length of one centimetre (1 cm) is assumed to be exceeded. In this case the
bounded-square output power is measured by a radiation force balance using an
intermediate absorbing mask with a one-square centimetre window (the mask is 1 cm × 1 cm
square), or by other masking means (e.g. electronic), or the bounded-square output power
may be measured via hydrophone planar scanning.
NOTE Temperature rise in tissue due to transducer surface self-heating has not been taken into account in the
determination of the thermal index [10] (see Annex C).
A.4.2.1 Derivation of break-point depth
Add, after "where A is the output beam area" in the second paragraph, the following new
ob
note:
NOTE 1 Equation (A.3) is a re-statement of Equation (8) (from 3.28), with a single pulse corresponding to a
non-scanning mode.
Table A.2 – Consolidated thermal index formulae
Delete, in the row labelled "C", the symbols "= TIB ".
as
A.4.3.4 Derivation notes for bone at-focus for non-scanning modes (TIB )
bs,ns
Replace, in the definition list below Equation (A.17), the words "I is spatial-average
sata
temporal-average intensity" by "I is the attenuated spatial-average temporal-average
,
sata α
intensity".
Replace, in the fourth paragraph, the words "Since output power…" by "Since attenuated
output power …".
)
A.4.3.6 Derivation notes for bone at-surface [TIC] for non-scanning modes (TIB
as,ns
and for scanning modes (TIB )
as,sc
" by "TIC " and "TIB " by "TIC ".
Replace, in the subclause's title, "TIB
as,ns ns as,sc sc
Replace the existing Note 2 by the following new note:
NOTE 2 For non-scanning modes D is calculated as described in A.4.2.1 and in 3.28 using the output beam

eq
area A , and for scanning modes D is calculated as described in 3.28 using the scanned aperture area A .
ob eq sa
B.1 General
Replace the last sentence of the fourth paragraph by "Steered beams are dealt with in the
same way".
Replace, in the sixth paragraph, "20 %" by "30 %".
Delete, in Note 2, the words "Edition 2".

– 16 – IEC 62359:2010/AMD1:2017
© IEC 2017
B.4.1 General
Replace the existing second paragraph by the following new paragraph:
The two techniques of defining the apertures in Clause B.4 have somewhat different sources
of error. Agreement of the compared results from these methods, or compared to results from
the method of Clause B.5, should give reasonable confidence that the aperture is defined
accurately. Use of these methods, absorbing mask (B.4.2) or absorbing target (B.4.3), to limit
detection to a 1 cm × 1 cm area at the front surface of the active scan aperture is
recommended when the method of Clause B.5 is not feasible (e.g. for testing mechanically
scanned sector probes, or third-party testing of all ultrasonic transducers).
B.4.2 1 cm × 1 cm aperture in a mask
Replace, in the last sentence of the note, the words "beam-width" by "beam width".
Figure B.4 – Suggested orientation of transducer and 1 cm-square RFB target
Replace, the axis labelling "Mask x or y axis" by "Target x or y axis".
B.5 Creating a 1 cm × 1 cm window using electronic control
Add, at the end of the clause's title, the words "or using calculations".
Replace, in last paragraph, the two occurrences of "mathematically" by "mathematical".
Delete, in the last paragraph, the last sentence.
B.6 Measurement of bounded-square output power
Replace, in the first paragraph, the words "of B.4.2 or B.4.3 to mask" by "of B.4.2 or B.4.3 or
Clause B.5 to eliminate".
Replace, in the second paragraph, the words "in either B.4.2 or B.4.3" by "in either B.4.2 or
Clause B.5, or the target used in B.4.3".
E.1 General
Add, after the last paragraph, the following new paragraph and note:
Annex F was added to Edition 2 of this standard to support the definition and determination of
maximum positions and values of I , I , I and I specified by IEC 60601-2-37.
spta spta,α sppa sppa,α
NOTE Similar to the below-surface TI values, these are also specified to be found on the beam axis beyond the
break-point depth z .
bp
E.2 Differences from IEC 62359 Edition 1
Add, after the third paragraph "Table E.1 summarizes some of the major changes", the
following new note:
NOTE The I (z ) and I (z ) values shown in Table E.1 are not the "maximum" attenuated spatial-
,
spta,α b,ns spta α s,ns
peak temporal-average intensity values described in Annex F, because they are at the depth for TIB and the
depth for TIS, respectively.
IEC 62359:2010/AMD1:2017 – 17 –
© IEC 2017
Add, at the end of the existing text in the first row, right column of Table E.1, the following
new sentence:
z is also applied to I , I , I and I determination described in Annex F.
, ,
bp spta spta α sppa sppa α
Add, after Annex E, the following new Annex F:

– 18 – IEC 62359:2010/AMD1:2017
© IEC 2017
Annex F
(informative)
Rationale and determination of maximum non-attenuated
and attenuated spatial-peak temporal-average intensity
and spatial-peak pulse-average intensity values
F.1 Rationale
This standard establishes parameters and methods related to thermal and non-thermal
exposure aspects of diagnostic ultrasonic fields sufficient to calculate mechanical index (MI)
and thermal index (TI) for display as specified in IEC 60601-2-37.
In the process of describing the determination of the thermal index and the mechanical
index, this standard defines and describes the key components for deriving maximum non-
attenuated and attenuated spatial-peak temporal-average and spatial-peak pulse-average
intensities at any depth z in the acoustic field. Meanwhile, the acoustic output reporting tables
specified in IEC 60601-2-37 require the provision of the spatial maximum values of these
parameters in the acoustic field at specific depths z; including providing spatial maximum
values over all depths z on the beam axis beyond the break-point depth, and "local" spatial
maximum values at other depths on the beam axis.
NOTE 1 Other interested parties also require provision of these parameters at ‘global’ spatial maximum positions,
and in some cases have established regulatory limits on their values.
NOTE 2 Recall from the definitions in Clause 3 that "spatial peak" in the terms "attenuated spatial-peak
temporal-average intensity" and "attenuated spatial-peak pulse-average intensity" is the peak value at a given
depth, z (i.e. not the peak value over all depths, z).
NOTE 3 The depths at which the MI and below-surface TIS and below-surface TIB are determined will not
generally be the same depths at which the maximum values of I , I , I or I occur.
spta spta,α sppa sppa,α
This standard refers to IEC 62127-1, IEC 62127-2 and IEC 62127-3 for definitions,
specifications of properties and calibration of measurement equipment and for hydrophone-
based measurement methods. IEC 62127-1 defines various acoustic parameters which can be
used to specify and characterize ultrasonic fields propagating in water using hydrophones.
IEC 61157 also defines various acoustic parameters which can be used to specify and
characterize ultrasonic fields propagating in water.
While these standards provide valuable information on the measurement of ultrasound fields,
they do not describe standardized determination of maximum non-attenuated or attenuated
spatial-peak temporal-average intensity, I and I nor non-attenuated or attenuated
,
spta spta α
spatial-peak pulse-average intensity I and I . Therefore, standardized means and
,
sppa sppa α
definitions for their determination are provided in Annex F.
In combination with IEC 62127 and IEC 61161, this standard describes a complete set of
methods for determining all acoustic output parameters for medical diagnostic ultrasonic
equipment used within the ultrasound community, including those parameters called for by
IEC 60601-2-37.
F.2 Overview
The goal of this Annex F is to describe standardized methods for determination of maximum
positions and values of non-attenuated and attenuated spatial-peak temporal-average
intensity I and I , and non-attenuated and attenuated spatial-peak pulse-average
,
spta spta α
intensity I and I , in the acoustic field of a medi
...