15-6 Acoustic Output
Probe
Max acoustic output
(mW/cm
2
)
Limited acoustic power when the acoustic output
is less than 10mW/cm
2
C5-2E
38.9
50.1
C7-3E
63.6
39.4
D7-2E
13.9
84.1
15.10 References for Acoustic Power and Safety
1.
“Bioeffects and Safety of Diagnostic Ultrasound” issued by AIUM in 1993
2.
“Medical Ultrasound Safety” issued by AIUM in 1994
3.
“Acoustic Output Measurement Standard for Diagnostic Ultrasound Equipment, Revision 3” issued
by AIUM/NEMA in 2004
4.
“Standard for real-time display of thermal and mechanical acoustic output indices on diagnostic
ultrasound equipment, Revision 2” issued by AIUM/NEMA in 2004
5.
“Information for Manufacturers Seeking Marketing Clearance of Diagnostic Ultrasound Systems and
Transducers” issued by FDA in 2008
6.
“Medical electrical equipment – Part 2-37: Particular requirements for the safety of ultrasonic
medical diagnostic and monitoring equipment” issued by IEC in 2007
15.10.1 Acoustic Output Data
This chapter describes the acoustic parameters for each exam and each mode with connecting the
ultrasound system to the appropriate probe.
15.10.2 Acoustic Parameter
p_
Peak-rarefactional pressure
I
spta
spatial peak temporal average acoustic intensityIspta
L
p
The distance between the output surface of the transducer and the
square integral points of the maximum pressure pulse.
W
pb6
Pulse beam width for -6dB
prr
Pulse repetition rate
srr
Scan repetition rate
Output beam size
On the output end of the transducer, vertical to the specific point on
the beam of the calibration axis (
－
6dB pulse beam width)
f
awf
arithmetic-mean acoustic-working frequency
APF,%
Acoustic power-on fraction. The ratio between the negative peak of
the sound pressure and the negative peak of the sound pressure
for some exact operations.
ALF,%
Acoustic initialization fraction. The ratio between the negative peak
of the sound pressure and the negative peak of the sound pressure
for some exact operations.
Max power
Maximum average acoustic output power hourly
