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Acoustic Output Limits
The ultrasound system maintains acoustic outputs below the appropriate limits for each application listed below.
Non ophthalmic applications:
System Probe I
SPTA.3
TI Type TI Value MI I
PA.3
@MI
max
Butterfly iQ™ 44.9 mW/cm
2
TIB 0.289 0.49 54.6 W/cm
2
Ophthalmic applications:
System Probe I
SPTA.3
TI Type TI Value MI I
PA.3
@MI
max
Butterfly iQ™ 8.12 mW/cm
2
TIB 0.047 0.162 6.48 W/cm
2
For additional information please visit support.butterflynetwork.com .
Acoustic Output Tables
Table 12. Symbols
Symbol Description
MI The Mechanical Index.
TISscan The Soft Tissue Thermal Index in an auto-scanning mode.
TIS
non-scan
The Soft Tissue Thermal Index in a non-auto-scanning mode.
TIB The Bone Thermal Index.
TIC The Cranial Thermal Index.
A
aprt
The area of the active aperture (square centimeters).
pr.
3
The derated peak rarefactional pressure associated with the transmit pattern giving rise to the value reported under MI (megapas-
cals).
Wo
The ultrasonic power, except for TISscan, in which case it is the ultrasonic power passing through a one centimeter window (milli-
watts).
W.
3
(z
1
) The derated ultrasonic power at axial distance z1 (milliwatts).
IT
A.3
(z
1
) The derated spatial-peak temporal-average intensity at axial distance z1 (milliwatts per square centimeter).
z
1
The axial distance corresponding to the location of max [min(W.
3
(z), I
TA.3
(z) x 1 cm
2
)], where z≥z
bp
(centimeters).
Z
bp
1.69√A
aprt
(centimeters).
z
sp
The axial distance at which TIB is a global maximum (i.e., z
sp
= z
B.3
) (centimeters).
z@PII
.3max
The axial distance corresponding to the maximum of the derated spatial- peak pulse intensity integral (megapascals).
d
eq
(z)
The equivalent beam diameter as a function of axial distance z. It is equal to [(4/
π
)(W
o
/I
TA
(z))]0.5 where ITA(z) is the temporal-
average intensity as a function of z (centimeters).
fc
The center frequency (MHz). For MI, f
c
is the center frequency associated with the transmit pattern giving rise to the global maxi-
mum reported value of MI. For TI, for combined modes involving transmit patterns of unequal center frequency, f
c
is defined as the
overall range of center frequencies of the respective transmit patterns.
Dim. of A
aprt
The active aperture dimensions for the azimuthal (x) and elevational (y) planes (centimeters).
PD The pulse duration (microseconds) associated with the transmit pattern giving rise to the reported value of MI.
PRF The pulse repetition frequency associated with the transmit pattern giving rise to the reported value of MI (Hz).
p
r
@PII
max
The peak rarefactional pressure at the point where the free-field, spatial peak pulse intensity integral is a maximum (megapascals).
See Section 6.2.4.1 of the Output Display Standard, entitled "Measurement Methodology for Mechanical and Thermal Indices".
d
eq
@PII
max
The equivalent beam diameter at the point where the free-field, spatial-peak pulse intensity integral is a maximum (centimeters).
See Section 6.2.5.1 of the Output Display Standard, entitled "Measurement Methodology for Mechanical and Thermal Indices".
FL The focal length, or azimuthal (x) and elevational (y) lengths, if different(centimeters).
I
PA.3
@MI
max
The derated pulse-average intensity at the point of global maximum reported MI (watts per square centimeter).
Acoustic Output
Specifications 47