Reference Manual 21
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 denitions and units of the symbols in those
tables are listed below, and are consistent with IEC 60601-2-37 and IEC 62359. Denitions 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 difcult 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 ags (‘**’) 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 cm2 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 -eld (non-
attenuated), PULSE INTENSITY INTEGRAL is a maximum (centimeters).
d
eq
(z
b
) the EQUIVALENT BEAM DIAMETER at axial distance zb. Equal to [(4/п)
(Pα(zb) / Ita,α(zb))]0.5. (centimeters)
Dim of Aaprt the –12 dB OUTPUT BEAM DIMENSIONS. The active apertu-re dimen-
sions 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, zat_max_Ipi,α . (watts per square centimeter).
Ita, 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 maxi-
mum TIS_scan value may (likely) come from a combinational mode. In this
case, P = P1 + P1x1. P1 is the BOUNDED OUTPUT POWER (the maxi-
mum 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. P1x1 is the ma-ximum contribution from any one square centimeter
of the non-scanned transmit mode(s) active aperture. (milliwatts).
P
α
(z) the (ultrasonic) ATTENUATED OUTPUT POWER at axial dist-ance zs, 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)
P
r
at max. I
pi
the PEAK-RAREFACTIONAL ACOUSTIC PRESSURE at the point where
the free -eld (non-attenuated), PULSE INTENSITY INTEGRAL is a maxi-
mum (megapascals).