Huntleigh MD2 User Manual

6
Safety
Acoustic intensity data (I
SPTA.3
) for probes available for use with the MD/SD2
are summarized in the following table. The values cited are based on
measurements in water using a calibrated hydrophone and are stated as
the estimated derated intensities. The derated intensity constitutes the most
biologically relevant parameter available since true determinations of actual
absorbed dose in tissue would require invasive measurement techniques. The
derated intensity is therefore calculated mathematically using a derating factor
consisting of a constant (the assumed attenuation coeffi cient) and allowing
for the frequency of the probe and the distance from the probe face to the
hydrophone.
The calculated derated intensity values for the MD/SD2 compare very favorably
with previously reported acoustic safety data for Doppler ultrasound instruments
and are appropriate for all clinical applications recommended in this manual.
As the operating mode of the Dopplex range of probes is continuous wave, I
SPPA
fi gures are not applicable.
Acoustic Output Table, Track1, Non-Auto-Scanning Mode
Model Max Value
I
SPTA.3
Wo f
c
Z
sp
A-6,
(Z
sp
)
EBD
OP2HS 55 41 2.0 2.5 1.1 1.2 x 2.5
OP3HS 55 32 3.0 2.0 1.2 1.2 x 2.5
VP4HS 92 7.5 4.0 0.8 0.14 0.365 x 0.8
VP5HS 92 8.2 5.0 0.8 0.12 0.365 x 0.8
VP8HS 92 4.0 8.0 0.48 0.026 0.215 x 0.5
EZ8 92 14.3 8.0 0.67 0.064 0.635 x 0.22
VP10HS 92 1.4 10.0 0.48 0.022 0.215 x 0.5
NOTES
1. Measurement uncertainty: varies with probe and measurement
Random - typically ±20% (max. ±32%)
Systematic - typically ±6.5% (max. ±8%)
Defi nition of Terms
I
SPTA.3
is the derated spatial-peak, temporal-average intensity (milliwatts
per square centimeter)
Wo is the ultrasonic power (milliwatts)
f
c
is the center frequency (MegaHertz)
Z
sp
is the axial distance used to calculate the derated intensity
(centimeters)
A-6 (Z
sp
) is (π /4) x (X-6 x Y-6) where X-6, Y-6 are respectively the in-plane
(azimuthal) and out-of-plane (elevational) -6dB dimensions in the X-Y
plane where Zsp is found (centimeters)
EBD are the entrance beam dimensions for the azimuthal and elevational
planes (centimeters)

Huntleigh MD2 Specifications

General

Brand	Huntleigh
Model	MD2
Category	Medical Equipment
Language	English