GE Vscan Extend User Manual page 46

Safety
Acoustic output and display on Vscan Extend
Display Accuracy and Acoustic Measurement Uncertainties
Parameter
Pressure, MI
Power, TI
2-20
MI and TI values are displayed on the scanning screen.
The maximum possible MI and Ispta on the Vscan Extend is
within the limits set in Track 3 in the FDA guidance of
September 9, 2008 for diagnostic ultrasound systems and
transducers, MI <1.9 and Ispta <720 mW/cm
The display accuracy and measurement precision of the output
display are summarized in the table below. Accuracy of the
output display (TI, MI) parameters depends on the
measurement system precision, the acoustic model used to
calculate the parameters and variation in the acoustic output of
probes and systems. The measurement precision and overall
accuracy of the measurements have been assessed by
determining both the random and the systematic uncertainties
and given in percent at 95% confidence level.
Table 2-5:
Estimated accuracy
±25%
±50%
a. Accuracy = (Measured value - displayed value)/displayed
value * 100%
Display accuracy
a
Measurement precision
±15%
±40%
Vscan Extend
2
.
black and white/color
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User Manual
5721203-100 Rev. D