Definitions And Symbols - Mcube CUBEscan BioCon-500 User Manual

9.3

Definitions and symbols

MI
the Mechanical Index
TIS the Soft Tissue Thermal Index in an auto-scanning mode
scan
TIS the Soft Tissue Thermal Index in a non-auto-scanning mode.
non-scan
TIB
the Bone Thermal Index.
TIC the Cranial Thermal Index.
A the area of the active aperture (square centimeters).
aprt
p
the derated peak rarefractional pressure associated with the transmit
r.3
pattern giving rise to the value reported under MI (megapascals)
W For TIB and TIC: time average acoustic power at the source, in
o
milliwatts. (Also see the definitions for W
For TIS scan, W
For TIS non–scan, W
W
combinational modes: time average acoustic power at the source, per
cm, in milliwatts. This is the acoustic power emitted from the central
1–cm length, in the scan direction, of the aperture corresponding to
the scanned pulses.
W
of combinational modes: time average acoustic power at the source,
per cm
central 1 cm
highest acoustic power is being transmitted.
W (z ) the derated ultrasonic power at axial distance z
.3 1
I (z ) the derated spatial-peak, temporal-average intensity at axial distance
TA.3 1
z
1
z the axial distance corresponding to the location of max[min(W
1
I
TA.3
1.69 A
z
bp
z For MI, the axial distance at which p
sp
z
sp
d (z)
the equivalent beam diameter as a function of axial distance z, and is
eq
equal to [(4/ )(W
intensity as a function of z (centimeters).
W
o = o1 +
o =
For scanning modes and/or scanning components of
o1:
For non–scanning modes and/or non–scanning components
o1x1:
2
, in milliwatts. This is the acoustic power emitted from the
2
of the active non–scanned aperture through which the
(milliwatts per square centimeter).
2
(z) x 1 cm )], where z = z
(centimeters).
aprt
for TIB, the axial distance at which TIB is a maximum (i.e.,
= z ) (centimeters).
B.3

/I
o TA
and W
01
W
o1x1
W
o1x1
(centimeters).
bp
is measured
r.3
0.5
(z))] where I (z) is the temporal-average
TA
89
that follow.)
01x1
(milliwatts).
1
(z),
.3