Reference Manual 115
Acoustic Power Tables
IEC Tables
Symbols and Definitions
Standard 60601-2-37 published by the International Electrotechnical Commission (IEC) requires the dec-
laration 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 Val-
ue (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’ (cm2)
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-attenu-
ated), PULSE INTENSITY INTEGRAL is a maximum (centimeters).
d
eq
(z
b
) the EQUIVALENT BEAM DIAMETER at axial distance zb. Equal to [(4/п)(P
α
(z
b
) /
I
ta,α
(z
b
))]
0.5
. (centimeters)
Dim of Aaprt 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 (FLx) and elevational (FLy), 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 = P1 + P
1x1.
P1 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. (mil-
liwatts).
P
α
(z) the (ultrasonic) ATTENUATED OUTPUT POWER at axial dist-ance z
s
, for the non-
scanned modes or TRANSMIT PATTERNS. (milliwatts)
P
r,α
the ATTENUATED PEAK-RAREFACTIONAL ACOUSTIC PRESSURE associated with the
transmit pattern giving rise to the reported value of MI. (megapascals)