IEC TS 62556:2014

IEC TS 62556 ®
Edition 1.0 2014-04
TECHNICAL
SPECIFICATION
colour
inside
Ultrasonics – Field characterization – Specification and measurement of field
parameters for high intensity therapeutic ultrasound (HITU) transducers and
systems
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IEC TS 62556 ®
Edition 1.0 2014-04
TECHNICAL
SPECIFICATION
colour
inside
Ultrasonics – Field characterization – Specification and measurement of field

parameters for high intensity therapeutic ultrasound (HITU) transducers and

systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XD
ICS 17.140.50 ISBN 978-2-8322-1505-0

– 2 – IEC TS 62556:2014 © IEC 2014
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 List of symbols . 31
5 Independent measurement of total acoustic output power . 33
6 Acoustic field measurement: equipment . 33
6.1 Hydrophone . 33
6.1.1 General . 33
6.1.2 Sensitivity of a hydrophone . 34
6.1.3 Directional response of a hydrophone . 34
6.1.4 Effective hydrophone radius . 34
6.1.5 Choice of the size of a hydrophone active element . 34
6.1.6 Hydrophone pressure limits . 35
6.1.7 Hydrophone intensity limits . 35
6.1.8 Hydrophone cable length and amplifiers . 36
6.2 Requirements for positioning and water baths . 36
6.2.1 General . 36
6.2.2 Positioning systems . 36
6.2.3 Water bath . 37
6.3 Requirements for data acquisition and analysis systems . 38
6.4 Requirements and recommendations for ultrasonic equipment being
characterized . 39
7 Measurement procedure . 39
7.1 General . 39
7.2 Preparation and alignment . 39
7.2.1 Initial adjustment to driving voltage . 39
7.2.2 Preparation of source transducer . 40
7.2.3 Aligning an ultrasonic transducer and hydrophone . 41
7.2.4 Beam-axis scan . 41
7.2.5 Measurements to be made at z = z . 41
p
7.2.6 Further evaluation for sidelobes and pre-focal maxima . 43
7.3 Considerations for scanning transducers and transducers with multiple
sources . 44
7.3.1 Automatic scanning transducers . 44
7.4 Linear extrapolation of field values . 44
7.4.1 General . 44
7.4.2 Calculation of I . 45
sal
7.4.3 Scaling for sidelobes and pre-focal maxima . 45
7.5 Reporting . 45
Annex A (informative) Rationale . 53
A.1 General . 53
A.2 Detailed discussion of difficulties in HITU field measurements . 53
A.2.1 Very high pressures . 53
A.2.2 Very high intensities . 54

A.2.3 Strong focusing . 54
A.2.4 Nonlinear harmonics . 54
A.2.5 Acoustic saturation and nonlinear loss . 55
A.2.6 Damage to hydrophones may only be apparent at high
pressures . 55
A.3 Approach of this technical specification . 55
Annex B (informative) Assessment of uncertainty in the acoustic quantities obtained
by hydrophone measurements . 57
B.1 General . 57
B.2 Overall (expanded) uncertainty . 57
B.3 Common sources of uncertainty . 57
Annex C (informative) Transducer and hydrophone positioning systems . 59
Annex D (informative) Rationale for I . 60
sal
D.1 General rationale . 60
D.2 Determination of P using hydrophone measurements and
c,6
extrapolation from linear measurements. 60
D.3 Alternative determination of P using an aperture in combination with a
c,6
measurement of total acoustic output power . 60
D.4 Special case of uniformly vibrating spherically shaped transducers . 61
Annex E (normative) Propagation and back-propagation methods for field
reconstruction: basic formulae and requirements . 62
E.1 Motivation and background . 62
E.2 Theory . 62
E.2.1 General . 62
E.2.2 Fourier projection approach . 64
E.2.3 Rayleigh integral approach . 67
E.3 Implementation . 68
E.3.1 General . 68
E.3.2 Recommendations for hydrophone . 68
E.3.3 Recommendation for planar scan parameters . 69
E.4 Assessment of uncertainties . 71
Annex F (informative) Propagation and back-propagation methods for field
reconstruction: examples and uses . 73
F.1 Examples . 73
F.1.1 Fourier projection example . 73
F.1.2 Rayleigh integral projection example . 77
F.2 Other propagation method applications . 81
Annex G (normative) Planar scanning of a hydrophone to determine acoustic output
power . 82
G.1 Introduction . 82
G.2 General principle. 82
G.3 Hydrophone scanning methodology . 83
G.3.1 General methodology . 83
G.3.2 Particular considerations for implementation for HITU fields . 84
G.4 Corrections and sources of measurement uncertainty . 84
G.4.1 Uncertainty in the hydrophone calibration . 84
G.4.2 Planar scanning . 84
G.4.3 Attenuation factor of water: unfocusing transducers . 85
G.4.4 Attenuation factor of water: focusing transducers . 85
G.4.5 Received hydrophone signal . 85

– 4 – IEC TS 62556:2014 © IEC 2014
G.4.6 Integration . 86
G.4.7 Finite size of the hydrophone . 86
G.4.8 partial extent of integration . 86
G.4.9 Non-linear propagation . 86
G.4.10 Directional response . 87
G.4.11 Noise . 87
G.4.12 Intensity approximated by derived intensity . 87
Annex H (informative) Properties of water . 88
H.1 General .
...