CEI EN 62359

This International standard is applicable to medical diagnostic
ultrasound fields.

This standard establishes

– parameters related to thermal and non-thermal exposure aspects
of diagnostic ultrasonic fields;

– methods for the determination of an exposure parameter
relating to temperature rise in theoretical tissue-equivalent
models, resulting from absorption of ultrasound;

– methods for the determination of an exposure parameter
appropriate to certain nonthermal effects.

NOTE 1 In Clause 3 of this standard, SI units are used (per
ISO/IEC Directives, Part 2, ed. 5, Annex I b) in the Notes below
definitions of certain parameters, such as beam areas and
intensities; it may be convenient to use decimal multiples or
submultiples in practice. Users must take care of decimal prefixes
used in combination with the units when using and calculating
numerical data. For example, beam area may be specified in
cm² and intensities in W/cm² or
mW/cm².

NOTE 2 Underlying calculations have been done from 0,25 MHz to
15 MHz for MI and 0,5 MHz to 15 MHz for TI.

NOTE 3 The thermal indices are steady state estimates based on
the acoustic output power required to produce a 1°C temperature
rise in tissue conforming to the "homogeneous tissue 0,3
dBcm^-1MHz^-1 attenuation model" [1 ]
¹⁾ and may not be appropriate for radiation force
imaging, or similar techniques that employ pulses or pulse bursts
of sufficient duration to create a significant transient
temperature rise. [2]