Safety
2.13.8 Notes
for
Acoustic
Output Tables for Track 3
Operating Conditions: means the adjustment of the scan parameters on the ultrasound console
MI:
is the Mechanical Index in an auto-scanning mode.
TISscan:
is the Soft Tissue Thermal Index in an auto-scanning mode.
TISnon-scan:
is the Soft Tissue Thermal Index in a non-auto scanning mode.
TIB:
is the Bone Thermal Index.
TIC:
is the Cranial Thermal Index.
Aaprt:
is the area of the active aperture (square centimeters).
pr.3:
is the derated Peak Rare factional Pressure (megapascals).
W0:
is the ultrasonic power, except for TISscan, in which case it is the ultrasonic power
passing through a one-centimeter window (mill watts).
W.3(z1):
is the derated ultrasonic power at axial distance z1.
ISPTA.3(z1): is the derated spatial-peak, temporal-average intensity at axial distance z1 (mill watts
per square centimeters).
z1:
is the axial distance corresponding to the location of max[min(W.3(z).ITA.3(z) * 1
cm2)], where z³zbp (millimeters).
zbp:
is 1.69(Aaprt)
1/2.
For MI, zsp:
is the axial distance at which pr.3 is measured; for TIB, zsp is the axial distance at
which TIB is a maximum (i.e. zsp = zb.3) (millimeters).
deq(z):
is the equivalent beam diameter as a function of axial distance z, and is equal to
[(4/p)(W0/ITA(z))]
1/2, where ITA(z) is the temporal-average intensity as a function
of z (millimeters).
fc:
is the center frequency (megahertz).
EBD:
1 - 12
are the entrance beam dimensions for the azimuthal and elevational planes
(millimeters).
PD:
is the pulse duration (microseconds).
PRF:
is the pulse repetition frequency (kilohertz).
Voluson
®
730 - Instruction Manual
105838 Rev. 3
2-17
