96 Acoustic Power Tables
Acoustic Power Tables
IEC Tables
▐ Symbols and Definitions
Standard 60601-2-37 published by the International Electrotechnical Commission
(IEC) requires the declaration of acoustic output information. The definitions and
units of the symbols in those tables are listed below, and are consistent with IEC
60601-2-37 and IEC 62359. Definitions for CAPITALIZED parameters, if not
found here, can be found in the reference documents.
All table entries have been obtained at the operating conditions that give rise to
the Maximum Index Value (shown in the second row of the table). Due to the
complexities of the system user interface, it may be difficult to exactly replicate
the declared condition. Contact Medison for further information as needed.
Note that Medison provides information for both
of the TIS non-scanned columns.
The ‘Aaprt≤1’ (cm
2
) column is an ‘at_surface’ TIS value and the ‘Aaprt>1’ (cm
2
)
column is a ‘below surface’ TIS value. The tables will provide additional
informational flags (‘**’) in the event that the largest TIS non-scanned value is an
‘at_surface’ value with Aaprt > 1 cm
2
, or if the largest TIS non-scanned value is a
‘below_surface’ value with Aaprt ≤ 1 cm
2
case (very rare).
A
aprt
the –12 dB OUTPUT BEAM AREA, or transmit aperture area,
of the ultrasonic beam. Derived from the –12 dB OUTPUT
BEAM DIMENSIONS. (centimeters squared)
d
eq
at max. I
pi
the EQUIVALENT BEAM DIAMETER at the point where the
free-field (non-attenuated), PULSE INTENSITY INTEGRAL is a
maximum (centimeters).
d
eq(
z
b)
the EQUIVALENT BEAM DIAMETER at axial distance z
b
.
Equal to [(4/п)(P
α
(z
b
) / I
ta,α
(z
b
))]
0.5
. (centimeters)
Dim of A
aprt
the –12 dB OUTPUT BEAM DIMENSIONS. The active
apertu-re dimensions in the azimuthal and elevational
directions. (cent-imeters). For scanned modes, the ‘X_dim’ is
the length of the entire scanned aperture.
f
awf
the ACOUSTIC WORKING FREQUENCY. Center frequency.
(megahertz)
Focal Length The nominal focal points, azimuthal (FL
x
) and elevational (FL
y
),
for the operating condition. (centimeters).
I
pa,α
at max. MI the ATTENUATED PULSE-AVERAGE INTENSITY at the
depth of reported MI,
z
at_max_Ipi,
α
.
(watts per square
centimeter).
I
ta, α
(z)
the ATTENUATED TEMPORAL-AVERAGE INTENSITY at
axial distance z
.
(milliwatts per square centimeter)
MI the displayed parameter representing potential cavitation bio-
effects. (unit-less)
P the time-average ultrasonic OUTPUT POWER radiated by the
transducer for the transmit pattern(s) associated with the
report-ed Index. For TIS_non_scan and TIB_non_scan this is
the total acoustic power of the non-scanned beam(s). For TIC
it is the total acoustic power of the contributing modes (which
will be list-ed separately, for the reader to sum). The reported
maximum TIS_scan value may (likely) come from a
combinational mode. In this case, P = P
1
+ P
1x1
.
P
1
is the
BOUNDED OUTPUT POWER (the maximum power emitted
from a one cm width of the active (scanned) transmit aperture
of the transducer in the scan plane direction) of each the
scanned
transmit modes. For instance in 2D color mode
P1_2D and P1_Col will be listed. P
1x1
is the ma-ximum
contribution from any one square centimeter of the non-
scanned transmit mode(s) active aperture. (milliwatts).