Cooper Surgical Medasonics TRIA P338, Manual

Page: 10 / 13

Ultrasonic Output: TRIA™ Fetal Doppler
Max MI W
o
f
c
Z
sp
x
-6
(cm) EBD (cm)
Value (mW) (MHz) (cm) y
-6
(cm)
I
SPTA0.3
20.1 0.0162 3.79 2.40 11.7 0.62 2.54 x 1.27
(mW/cm 2 ) 2.0 semicircle
I
SPTA0.3
0.0201 0.0162 3.79 2.40 11.7 0.62 2.54 x 1.27
(W/cm 2 ) 2.0 semicircle
Ultrasonic Output: TRIA ™ Vascular Doppler
Max MI W
o
f
c
Z
sp
x
-6
(cm) EBD (cm)
Value (mW) (MHz) (cm) y
-6
(cm)
I
SPTA0.3
3.3 0.0448 7.1 5.20 1.1 0.3 0.94 x 0.47
(mW/cm 2 ) 0.75 semicircle
I
SPTA0.3
0.0033 0.0448 7.1 5.20 1.1 0.3 0.94 x 0.47
(W/cm 2 ) 0.75 semicircle
Data for ultrasonic output tables reported as maximum value. Data for IEC
1157 table reported as maximum value plus 95% confidence interval.
The derated value of the acoustic intensities are calculated according to the fol-
lowing formula:
I
0.3
= I
w
exp(-0.069f
c
z
sp
)
where I
0.3
is the derated intensity in mW/cm 2 , I
w
is the intensity measured in
water per NEMA UD-2, f
c
is the center frequency of the transducer in MHz, and
z
sp
is the location of the axial spatial peak in cm.
- 18 - - 17 -
Definition of Terms (Ultrasonic Output Tables)
**Note:
The uncertainty in these measurements was calculated per
NEMA UD-2 Appendix A to be 24%.
I
SPTA0.3
The derated spatial-peak, temporal-average intensity
(milliWatts per square centimeter)
I
SPTA0.3
The derated spatial-peak, pulse-average intensity
(watts per square centimeter)
MI The Mechanical Index
W
o
The ultrasonic power (milliWatts)
f
c
The center frequency (megaHertz)
Z
sp
The axial distance used to calculate the derated
intensity (millimeters)
EBD Entrance beam dimensions for the azimuthal and elevational
planes (centimeters)
x
-6
,y
-6
Beam dimensions at spatial peak (cm)
PD Pulse Duration (microseconds)
PRF Pulse Repetition Rate (Hz)
Data for ultrasonic output tables reported as maximum value.
The derated value of the acoustic intensities are calculated according to the
following formula:
I
0.3
= I
w
exp(-0.069f
c
z
sp
)
Where I
0.3
is the derated intensity in mW/cm 2 , I
w
is the intensity measured in
water per NEMA UD-2, f
c
is the center frequency of the transducer in MHz, and
z
sp
is the location of the axial spatial peak in cm.