IEC TS 62462:2007

TECHNICAL IEC
SPECIFICATION TS 62462
First edition
2007-05
Ultrasonics – Output test –
Guide for the maintenance of
ultrasound physiotherapy systems
Reference number
IEC/TS 62462:2007(E)
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TECHNICAL IEC
SPECIFICATION TS 62462
First edition
2007-05
Ultrasonics – Output test –
Guide for the maintenance of
ultrasound physiotherapy systems
PRICE CODE
Commission Electrotechnique Internationale U

International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – TS 62462 © IEC:2007(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Testing regimes.7
4.1 Acceptance testing .7
4.2 Weekly testing.7
4.3 Annual testing .7
5 Performance testing .8
5.1 Acceptance testing .8
5.2 Weekly testing.9
5.3 Annual testing .10
5.4 Service requirement .12

Annex A (informative) Rationale for testing .14
Annex B (informative) Guidance for testers.15
Annex C (informative) Quantitative relative ultrasonic output test using temperature
rise .19
Annex D (informative) Quantitative relative ultrasonic output test using calorimetry .21
Annex E (informative) Example of weekly test report .23
Annex F (informative) Example of annual test report .24
Annex G (informative) Ultrasound portable power standard.28

Bibliography.29

Figure 1 – Several examples of how to prepare a set-up to check the distortion on the
water surface due to ultrasound .12
Figure 2 – Set-up where the slight angle of the treatment head to the vertical may
improve the image .13
Figure C.1 – Example of a measurement set-up to measure the temperature rise due to

ultrasound in absorbing material. .20
Figure D.1 – Schematic of equipment used within the calorimeter method for
monitoring power output of therapy treatment heads.21
Figure F.1 – Example of a power calibration graph for a large applicator head.26
Figure F.1 – Example of a power calibration graph for a large applicator head.26
Figure F.2 – Example of a power calibration graph for a small applicator head .27

TS 62462 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_______________
ULTRASONICS – OUTPUT TEST –
GUIDE FOR THE MAINTENANCE OF ULTRASOUND
PHYSIOTHERAPY SYSTEMS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
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The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC 62462, which is a technical specification, has been prepared by IEC technical committee
87: Ultrasonics.
– 4 – TS 62462 © IEC:2007(E)
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
87/350/DTS 87/362/RVC
Full information on the voting for the approval of this technical specification 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.
NOTE The following print types are used:
• requirements: roman type;
• notes: in small roman type;
• words in bold in the text are defined in Clause 3.
• numbers in square brackets refer to the Bibliography.
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
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

TS 62462 © IEC:2007(E) – 5 –
INTRODUCTION
The purpose of this technical specification is to establish standard methods for a qualitative
check of the performance of ultrasound physiotherapy devices during their lifetime, and to
provide guidance on calibration requirements and techniques.
To ensure that the ultrasound physiotherapy equipment is in an appropriate condition for use,
a regular quality check is necessary. This technical specification defines acceptance, weekly
and annual checks. The acceptance test checks the delivery of the device and its
performance at the start of its lifetime. The weekly check is a simple qualitative check of
device operation. In the annual check, in addition to a qualitative check, a quantitative check
is defined. Examples are provided of weekly and annual test reports.
This report also gives guidance to the testers concerning the measurement of acoustic output.
Annual testing is to be performed by a skilled tester, e.g. biomedical engineer, medical
physicist, medical device service agent, commercial tester, test house, national measurement
institute or manufacturer.
– 6 – TS 62462 © IEC:2007(E)
ULTRASONICS – OUTPUT TEST –
GUIDE FOR THE MAINTENANCE OF ULTRASOUND
PHYSIOTHERAPY SYSTEMS
1 Scope
This technical specification describes methods meant to assist users of ultrasound therapy
machines in checking the performance of such machines. It is applicable primarily to
physiotherapists, general medical practitioners, chiropractors, osteopaths, beauty therapists,
sports professionals, biomedical engineers, medical physicists, medical device service
agents, commercial testers, test houses or manufacturers.
NOTE The titles of all publications referred to informatively in this technical specification are listed in the
Bibliography.
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 61689:2007, Ultrasonics – Physiotherapy systems – Performance requirements and
methods of measurement in the frequency range 0,5 MHz to 5 MHz
IEC 61161:2006, Ultrasonics – Power measurement – Radiation force balances and
performance requirements
IEC 60601-2-5, Medical electrical equipment – Part 2-5: Particular requirements for the safety
of ultrasonic physiotherapy equipment
BIPM, IEC, IFCC, ISO, IUPAC, IUPAP and OIML, Guide to the expression of uncertainty in
measurement
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE Most of the definitions described are taken from existing IEC standards. For use in the present guide such
definitions are simplified.
3.1
acoustic working frequency
rate at which the treatment head’s contact face is vibrating

[IEC 61689:2007, definition 3.3, simplified]
NOTE Typical ultrasound physio-therapy machines operate in the range from 0,7 MHz to 3,3 MHz. Long-wave
ultrasound therapy machines operating in the frequency range 30 kHz to less than 1 MHz are not covered by the
present document. Usually the boundary between sound and ultrasound is 20 kHz.
3.2
beam non-uniformity ratio
R
BN
a measure of the range of non-uniformity in the ultrasound beam produced by the treatment
head, calculated from the ratio of the acoustic intensity measured at the most intense part of
the ultrasound beam to the spatial average acoustic intensity measured for that treatment
head
[IEC 61689:2007, definition 3.9, simplified]

TS 62462 © IEC:2007(E) – 7 –
3.3
degassed water
water with a low dissolved gas content (see IEC 61161 and Clause B.3)
NOTE For ultrasound physiotherapy fields it is sufficient to decrease the oxygen content below 4 ppm.
3.4
effective radiating area
A
ER
area of the front of the treatment face from which ultrasound is being emitted/radiated
[IEC 61689:2007, definition 3.19, simplified]
3.5
hot spot
a localized peaking of the pressure distribution above values that normally can be expected
when the ultrasonic beam has been emitted from a piston source. It is called a hot spot when
the beam non-uniformity ratio (R ) > 4
BN
3.6
effective intensity
amount of ultrasonic energy flowing per second through an area and divided by that area
[IEC 61689:2007, definition 3.17, simplified]
3.7
output power
a measure of how much ultrasonic energy is flowing out of the treatment head per second
[IEC 61161:2006, definition 3.3, simplified]
3.8
tester
person who does performance testing on, or calibration of, therapy machines
3.9
treatment head
assembly comprising one ultrasonic transducer and associated parts for local application of
ultrasound to the patient
(see IEC 60601-2-5)
4 Testing regimes
4.1 Acceptance testing
After the device has been delivered to the user a first test should be performed to record the
performance at the start of the device’s lifetime.
4.2 Weekly testing
Weekly qualitative testing is performed by the therapy machine user, e.g. physiotherapist,
general medical practitioner, chiropractor, osteopath, beauty therapist, sports professional.
4.3 Annual testing
Annual testing is performed by an accredited tester, e.g. biomedical engineer, medical
physicist, medical device service agent, commercial tester, test house, national measurement
institute, manufacturer.
– 8 – TS 62462 © IEC:2007(E)
5 Performance testing
5.1 Acceptance testing
The purpose of the test is to record the performance of a device before clinical use, or of a
device that has been repaired. The test involves a manufacturer’s statement, a visual
inspection and a quantitative relative ultrasonic output test.
5.1.1 Visual inspection
The first visual inspection should concentrate on the delivered items. All items should have
been delivered in accordance with the purchase specification, and they should look
undamaged.
5.1.2 Manufacturer’s statement
On delivery of either a new device or after repair of an existing device check the written
system manufacturer’s statement that the device performs in accordance with the
manufacturer’s device specifications. From this statement it shall follow that the device is
traceably calibrated in accordance with IEC 61689 and IEC 60601-2-5.
5.1.3 Quantitative relative ultrasonic output test
a) To prepare a starting point for future simple quantitative output testing, either the effective
intensity or the ultrasonic output power of the device should be recorded for at least one
output setting, e.g. continuous wave, effective intensity: 1 W/cm .
b) In cases where the manufacturer has stated the traceability of the calibration there is no
need for an absolute output measurement. In all other cases the ultrasonic output should
be calibrated in accordance with IEC 60601-2-5 and IEC 61161.
c) Once confidence is established in the calibration of the device, a prescribed method
should be used to relate the device output setting as recorded in 5.1.3 a) to a reading of a
related performance. This method could be a determination of temperature rise following
Annex C or Annex D, or using a wattmeter. The method used should be described in the
record and should be used in the weekly test, see 5.2.2.
5.1.4 Beam uniformity and output test
5.1.4.1 General
The test is a quick check of whether the machine is outputting any ultrasound power, and of
any ‘hot spots’ or asymmetry present in the beam produced by the treatment head. It is not a
power calibration. The technique uses the ultrasound emitted by the treatment head to disturb
the surface of water in a container. The equipment needed is as follows:
a) a small container of sufficient depth to be filled with water to a maximum of 25 mm. This
container should have a bottom thickness of <0,3 mm. See Figure 1 for a number of
examples;
b) coupling gel.
NOTE Common, undesirable techniques which have been used in the past to check ultrasound output are as
follows:
(a) placing a few drops of water on the upturned treatment head, then timing how long it takes for the water to
boil off.
(b) making a small well of water about the treatment head using some tape, and observing the disturbance of the
water surface by the ultrasound.
Modern physiotherapy units have automatic cut-offs (power down) when the treatment head has insufficient contact
with the patient or is not immersed. Techniques such as those described in Items (a) and (b) above will often
trigger the automatic shutdown of the head and thus give a false indication that the ultrasound therapy machine is
faulty.
TS 62462 © IEC:2007(E) – 9 –
Subjecting a treatment head to poor patient contact or poor water immersion will shorten the lifetime of the device.
For these reasons, using a container of water to see the effect of the ultrasound on a surface of water is highly
advisable.
1)
Further valuable reading can be found in [1],[2],[3],[4] .
5.1.4.2 Procedure
The procedure is as follows.
a) Hold the treatment head so that the face is pointing upwards. Apply coupling gel to the
face of the treatment head. Place the container on the face of the treatment head and
make sure that all coupling gel is properly distributed without air bubbles. See Figure 1.
b) Fill the container with water to a depth of 5 mm to 20 mm. (Tap water is adequate for this
qualitative and quick test.)
c) A slight angle of the treatment head to the vertical may improve the image. See Figure 2.
d) Turn on the ultrasound to full power, or less if this is sufficient to observe a disturbance of
the water. (A disturbance of the water will be observed when looking from the side, and it
may be necessary to move the treatment head around a little and to also change the angle
to the surface to see the disturbance. The effect which can be seen is shown in Figure 1.)
If the treatment head is <5 mm below the surface and/or exactly parallel to it, then the
ultrasound may turn off due to an automatic safety sensor, as damage to the ultrasound
therapy machine may otherwise occur.
The features of the water disturbance to note are as follows:
1) the circular symmetry of the pattern;
NOTE Changes in the circular symmetry can be an indication of changes in the effective radiating area.
2) whether there are any sharp peaks (hot spots) showing (see Figure 1(c));
3) whether the appearance of the disturbance changed in height or symmetry since the
last time it was checked;
4) whether the pattern remained the same but decreased in height with reduction in
ultrasound power.
5.1.5 Recording of results of acceptance test
The results of the acceptance test shall be recorded. Annex E gives an example where the
results of the acceptance test can be recorded as a start of the weekly test report.
5.1.6 Requirements / Recommendation
Patterns obtained by performing 5.1.4, which are not circularly symmetric and/or have sharp
peaks, indicate that the treatment head may not be performing appropriately and could be
unsafe.
In case of non-conformance with one of the events listed in 5.1.1, 5.1.2, 5.1.3, 5.1.4, the
manufacturer should be consulted to check the device.
5.2 Weekly testing
Weekly testing involves a simple and quick procedure for testing the ultrasonic output
relatively and visual inspection of aspects such as cable damage.
5.2.1 Visual inspection
The ultrasound therapy machine should be inspected visually on aspects that could affect
proper safe functioning, such as a damaged mains or treatment head cable or connector.
—————————
1)
Figures in square brackets refer to the Bibliography.

– 10 – TS 62462 © IEC:2007(E)
5.2.2 Relative ultrasonic output test
The ultrasonic output should be measured using the same method described in 5.1.3 c) and at
the same settings as used during the acceptance test.
The result should not deviate by more than 25 % of the value determined during the
acceptance test
5.2.3 Beam uniformity and output test
The beam uniformity can be tested using the same method described in 5.1.4.
5.2.4 Recording of results of weekly testing
The results of the weekly test should be recorded. Annex E gives an example of a weekly test
report.
5.2.5 Requirements / Recommendation
Patterns obtained by performing 5.2.3, which are not circularly symmetric and/or have sharp
peaks, indicate that the treatment head may not be performing appropriately and could be
unsafe. Unexpected patterns may identify future failure.
If the case of non-conformance of any of the tests listed in 5.2.1, 5.2.2, 5.2.3 the
manufacturer should be consulted to check the device.
5.3 Annual testing
The purpose of the test for evaluating beam uniformity is that it gives the healthcare
professional some guidance as to whether the treatment heads are beginning to deviate
significantly from the desired norm.
The equipment used to perform the annual testing shall be calibrated traceably to a higher
standard. (See Annex F).
5.3.1 Output power test
For each treatment head and at the intended frequencies of operation the actual ultrasound
output power shall be measured in accordance with IEC 61161.
The ultrasound power should be measured at the indicated values (or as close as possible for
machine settings) which are 10 %, 25 %, 50 % and 100 % of the maximum. This is done at
least twice with the treatment head being removed from the power meter and then reattached
for the second series of readings. Annex F gives an example of the annual ultrasound power
calibration test report. The results obtained are directly plotted onto the appropriate graph of
the report.
The power measured shall be within ±20 % of that indicated on the device.
Check that a power setting of 0 W does not deliver any ultrasound.
5.3.2 Effective radiating area
Most therapeutic treatments are based on the effective intensity. This intensity is equal to the
ratio of the ultrasonic power over the effective radiating area. So apart from calibrating the
ultrasonic power, the size of the effective radiating area is also of importance. Eventual
changes of this area can be observed using the beam uniformity test in 5.1.4.

TS 62462 © IEC:2007(E) – 11 –
5.3.3 Beam uniformity test
The annual beam uniformity test is performed in the same manner as the weekly test for beam
uniformity, see 5.1.4.
5.3.4 Pulse regime accuracy test
The performance of the pulse regime is not expected to change significantly from year to
year. The test can be with an ultrasound power meter or an oscilloscope using a non-invasive
current probe. For all measurements it is necessary for the treatment head to be immersed in
water. For a given machine, it is sufficient to test a single treatment head and only at full
power.
NOTE The test is optional as it is not expected that this parameter will change over time.
5.3.4.1 Using an ultrasound power meter
The power at continuous wave mode operation (100 % duty) should be measured and then
compared with the power obtained for the range of pulsing regimes available on the machine.
The power measured under the pulsing regime should be within ±5 % of that calculated using
the pulse regime factor with the continuous power value.
5.3.4.2 Using an oscilloscope
Confirmation is needed that the amplitude is the same as for continuous wave mode (to within
±5 %) and that the pulse duty cycle is as indicated on the machine, to within ±5 %.
NOTE A way of performing the measurement is to clamp a current probe around the cable to the treatment head
and then observing the pulse regime on the oscilloscope.
5.3.5 Timer accuracy test
The performance of the timer accuracy is not expected to change significantly from year to
year.
The test can be performed using a stopwatch. The ultrasound machine’s timer should be
accurate to within ±10 %.
NOTE The test is optional as it is not expected that this parameter will change over time. For this reason the test
is also simplified from the test described in IEC 60601-2-5.
5.3.6 Recording of results of annual testing
The results of the annual test should be recorded. Annex F gives an example of an annual
test report.
The measurement of uncertainty shall be estimated using the ISO/IEC Guide to the
measurement.
The test report should record the following:
a) identification of the treatment head and machine tested. Serial numbers (S/N) are
important;
b) date of the maintenance test;
c) name of the accredited tester;
d) calibration date of the power meter;
e) beam uniformity test result;
...