EN 61157:2007 – Standard means for the reporting of the acoustic output of medical diagnostic ultrasonic equipment
1 Scope
This International Standard is applicable to medical diagnostic ultrasonic equipment.
– It provides a set of traceable acoustic parameters describing the acoustic fields.
– It defines a standard means and format for the reporting of the acoustic output information.
– It also describes a reduced dataset recommended for equipment generating low acoustic output levels.
NOTE The information tabulated in this standard format can be used for
a) exposure planning for biological effects studies;
b) exposure data for prospective epidemiological studies conducted using exposure conditions similar to those reported in this standard. In the absence of actual exposure data for retrospective epidemiological studies, the information tabulated in this standard format might also be used with cautionary comment.
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 60050-801 :1 994 International Electrotechnical Vocabulary – Chapter 801: Acoustics and electroacoustics
IEC 61 1 61 , Ultrasonics – Power measurement – Radiation force balances and performance requirements
IEC 621 27-1 , Ultrasonics – Hydrophones – Part 1: Measurement and characterization of medical ultrasonic fields up to 40 MHz
ISO 1 6269-6:2005, Statistical interpretation of data – Part 6: Determination of statistical tolerance intervals
ISO/IEC Guide 98:1 995, Guide to the expression of uncertainty in measurement (GUM)
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in IEC 621 27-1 , IEC 61 1 61 ,the Index of defined terms at the end of this standard and the following definitions apply.
Figures C.1 to C.4 illustrate some of the defined parameters given below.
3.1
acoustic output freeze
condition of a system for which the acoustic output is disabled when there is no active updating of ultrasonic echo information
3.2
acoustic pulse waveform
temporal waveform of the instantaneous acoustic pressure at a specified position in an acoustic field and displayed over a period sufficiently long to include all significant acoustic information in a single pulse or tone-burst, or in one or more cycles in a continuous wave NOTE 1 Temporal waveform is a representation (e.g. oscilloscope presentation or equation) of the instantaneous acoustic pressure.
NOTE 2 Definition adapted from IEC 60469-1 .
3.3
acoustic repetition period
arp
pulse repetition period for non-automatic scanning systems and the scan repetition period for automatic scanning systems, equal to the time interval between corresponding points of consecutive cycles for continuous wave systems
NOTE 1 The acoustic repetition period is expressed in seconds (s).
[IEC 621 27-1 , definition 3.2]
3.4
acoustic frequency
acoustic-working frequency
frequency of an acoustic signal based on the observation of the output of a hydrophone placed in an acoustic field at the position corresponding to the spatial-peak temporal-peak acoustic pressure
EN 61157:2007 – Standard means for the reporting of the acoustic output of medical diagnostic ultrasonic equipment