Gammex 1425A, User Manual

7

Evaluating the B-Mode System

Remember

A 4.5 MHz probe will provide a good overall view of the phantom for this demonstration.

1.

To couple with water, fill the dam with distilled water. For a better image quality, use gel.

2.

Rest the transducer on the scanning surface. Adjust the scanner to display the full depth of 
the phantom. 

You may notice that the tissue echoes near the bottom of the phantom fade into noise. The 
depth at which usable echoes disappear is called the 

depth of penetration

. The depth 

markers on the phantom label will help you determine the depths of the targets.

3.

Move the transducer across the scanning surface while observing the locations of the 
targets.

Notice how the smooth texture of the tissue mimicking gel emphasizes image non-uniformi-
ties and artifacts, making them easier to detect.

Decrease gain controls to highlight pin targets.

4.

Scan the vertical pin targets and freeze the image. Use the electronic calipers to measure 
the distance between two of the vertical pin targets. Repeat for two of the horizontal pin 
targets. The vertical pins have 20 mm spacing while the horizontal pins have 30 mm spacing. 

Use the pin targets to determine

 vertical distance accuracy

 and

 horizontal distance accuracy

.

Note that the highest dead zone pin you can see should be the point of reference not the 
scanning surface.

•

The phantom comes ready to scan. Do not peel off the surface 
material.

•

Never press the transducer into the scanning surface.

•

Always clean and dry the scanning surface after each use. Never leave 
coupling gel or water on the scanning surface for more than a few 
hours.

•

Do no

t use mineral oil, baby oil, or lanolin-based gels as a coupling 

medium.