Clarius Scanner HD3 Safety Topics
revision 9 54
Estimates of the MI and TI display accuracies are shown in the Acoustic Output Tables. The
following factors are considered when estimating the accuracy of the displayed values:
• hardware variations
Variability among scanners and systems is a result of piezoelectric crystal efficiencies,
process-related impedance differences, and sensitive lens-focusing parameter
variations.
• estimation algorithm accuracy
Differences in system pulser voltage control and efficiencies are also contributors to
variability. There are inherent uncertainties in the algorithms used to estimate
acoustic output values over the range of possible system operating conditions and
pulser voltages.
• measurement variability
Inaccuracies in laboratory measurements can be caused by hydrophone calibration
and performance, positioning, alignment, and digitization tolerances, and variability
among test operators.
Controls Affecting Display Indices
Use system controls to change the TI and MI values.
Power Controls
Two real-time output values are on the display: TI and MI. These change as the system
responds to power-control adjustments. TI and/or MI values will be displayed whenever the
Index values exceeds 0.4 (dimensionless).
B-Mode Controls
• Focus:
When the focal depth is near the natural focus of the scanner, the MI may be higher.
Other Control Effects
• B-Mode Depth:
An increase in two-dimensional depth will automatically decrease the B-Mode frame
rate, thereby decreasing the TI. The system may also automatically choose a deeper
two-dimensional focal depth. A change of focal depth may change the MI. The MI
displayed is that of the zone with the largest MI value.
• Application:
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