GE LOGIQ 7, Basic User Manual

Page: 964 / 984

User Maintenance
18
-
36 LOGIQ 7 Online Help
Direction 2392536-100 Rev. 1
Penetration
Description Penetration is the ability of an imaging system to detect and
display weak echoes from small objects at large depths. See
Figure 18-11 for more information.
Penetration can be affected by the system's:
• Transmitter/receiver
•
Degree of probe focusing
• Attenuation of the medium
• Depth and shape of reflecting object
• Electromagnetic interference from local surroundings.
Benefit Weak reflecting echoes are commonly produced from the
internal structure of organs. Definition of this tissue texture is
important in the interpretation of the ultrasound findings.
Method Scan a phantom to see how echoes begin to fade as depth is
increased. The maximum depth of penetration is the point at
which homogeneous material in the phantom begins to lose
brightness.
Procedure To measure penetration:
1. Set the front panel TGC slide pots to their center (detent)
position.
2. Gain and acoustic output can be adjusted, as necessary,
since these values are displayed on the monitor.
3. Scan a test phantom along the vertical pin targets to typical
depths for the probe being used.
4. Perform a standard distance measurement from the top of
the image displayed to the point at which homogeneous
material in the phantom begins to lose brightness.
5. Document the depth measurement for reference and future
comparison.
Contact a Service Engineer if the depth of penetration shifts
more than one centimeter (1cm) when using the same probe
and same system settings.