User's Manual

Table Of Contents
139
12 Appendix
 Appendix D: Acoustic Output Reporting Tables for Track 3
InnoSight Ultrasound System
P6992-4, EN, 16/12/6
Appendix D: Acoustic Output Reporting Tables for Track 3
We follow Track 3 of the FDA’s information for manufacturers seeking marketing clearance of diagnostic
ultrasound systems and transducers All table entries have been obtained at the same operating conditions
that give rise to the maximum index value Due to the complexities of the system user interface, it may be
difficult to exactly replicate the declared condition For more information, contact Philips
Definition of Terms Used in Acoustic Output Tables
Symbols used in the tables are described below:
: Acoustic attenuation coefficient is the coefficient intended to account for ultrasonic attenuation of tissue
between the source and a specified point
A
aprt
:
-12 dB output beam area
is the area of the ultrasonic beam derived from the
-12 dB output beam
dimensions
C
MI
: Normalizing coefficient
1 MPa MHz
-1/2
D
eq
: Equivalent aperture diameter is the diameter of a circle whose area is the
-12dB output beam area
and
given by
D
eq
A
aprt
4
d
-6
:
Pulse beam width
is the distance between two points, on a specified surface in a specified direction,
passing through the point of maximum pulse-pressure-squared integral (
p
i
) in that surface, at which the
pulse-pressure-squared integral
is a specified fraction of the maximum value in that surface
d
eq
:
Equivalent beam diameter
is the value of the diameter of the acoustic beam at the distance
z
, in terms
of the equivalent beam area, and given by
d
eq
(
z
) 
A
eq
(
z
)
4
f
awf
:
Acoustic working frequency
is the arithmetic mean of the most widely separated frequencies
f
1
and
f
2
at
which the amplitude of the pressure spectrum of the acoustic signal is 3 dB lower than the peak amplitude
I
pa
:
Pulse-average intensity
is the ratio of the
pulse-intensity integral I
pi
to the pulse duration
t
d
I
pa,
:
Attenuated pulse-average intensity
is the value of the
acoustic pulse-average intensity
after
attenuation and at a specified point and given by
I
pa, 
I
pa
(z)1
(

awf
/1)
I
pi
:
Pulse-intensity integral
is the time integral of the instantaneous intensity at a particular point in an
acoustic field integrated over the acoustic pulse waveform
I
pi,
:
Attenuated pulse-intensity integral
is the value of the pulse-intensity integral after attenuation, at a
specified point, and given by
I
pi, 
I
pi
10
(

awf
/1)
I
sppa, 
:
Attenuated spatial-peak pulse-average intensity
I
spta
:
Spatial-peak temporal-average intensity
I
spta, 
:
Attenuated spatial-peak temporal-average intensity
I
ta
(z)
:
Temporal-average intensity
is the time-average of the instantaneous intensity at a particular point in
an acoustic field
I
ta,
(z)
:
Attenuated temporal-average intensity
is the value of the
temporal-average intensity after
attenuation
, at a specified point, and given by
I
ta, 
(
z
) 
I
ta
(
z
)1
(

awf
/1)
I
zpta
(z)
:
Spatial-peak temporal-average intensity
is the maximum value of the
temporal-average intensity
in a
specified plane at a specified distance
z
from the transducer
I
zpta,
(
z
):
Attenuated spatial-peak temporal-average intensity
is the value of the
spatial-peak temporal-
average intensity
after attenuation, at a specified distance
z
, and given by
I
zpta, 
(
z
) 
I
zpta
(
z
)1
(

awf
/1)
MI
:
Mechanical index
is given by
MI
C
MI
P
ra
f
awf
-1/2
n
pps
: Number of pulses per ultrasonic scan line