User's Manual

Clarius Ultrasound Scanner - HD3 Scanners Safety Topics
revision 1 52
• 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:
Acoustic output defaults are set when you select an application. Factory defaults vary
with scanner, application, and mode. Defaults have been chosen below the FDA limits
for intended use.
• Imaging Mode Controls:
When a new imaging mode is selected, both the TI and MI may change to default
settings. Each mode has a corresponding pulse repetition frequency and maximum
intensity point. In combined or simultaneous modes, the TI is the sum of the
contribution from the modes enabled, and the displayed MI is the largest of the MI