Gammex 404GS LE User manual
404GS LE
Precision Small Parts
Grey Scale Phantom
Gammex
User’s Guide
2
Table of Contents
Introduction.............................................................................................................................3
Caringforyour404GSLE.......................................................................................................4
Scanning your 404GS LE .................................................................................................5
AGuidedTourofyour404GSLE.............................................................................................6
EvaluatingthePhantom..........................................................................................................7
Target Specifications.........................................................................................................12
Cystic Targets....................................................................................................................12
GreyScaleTargets..................................................................................................................12
PinTarget..............................................................................................................................12
ResolutionTargetGroup.......................................................................................................12
Phantom Specifications.....................................................................................................14
Physical Specification........................................................................................................14
Tissue Mimicking Background Material...............................................................................14
LowScatter(Anechoic)Cysts................................................................................................14
GreyScaleTargets..................................................................................................................14
HarmonicImaging.................................................................................................................15
System Linearity................................................................................................................17
Quantitative Measurement.................................................................................................19
Baseline Test.....................................................................................................................19
SubsequentTests.................................................................................................................19
Qualitative Measurement...................................................................................................20
Phantom Desiccation.........................................................................................................21
Charts and Graphs..............................................................................................................21
Product Warranty...............................................................................................................22
Sales and Service...............................................................................................................23
3
Introduction
The 404GS LE phantom is designed to measure the image quality of small parts and
intra-cavity ultrasound scanning systems. With added grey scale targets, this small parts
phantom can also be used to measure contrast, temporal resolution and system linear-
ity. This Small Parts Phantom permits precise measurements of resolution for testing
for:
• Axial and lateral resolution targets at 1, 3.5 and 6 cm for precise resolution mea-
surements
• Low scatter cyst imaging at 1, 2 and 4 mm
• Attenuation coefficients of either 0.5 or 0.7 dB/cm/MHz
• 7 mm cyst to evaluate system noise and distortion and 7 mm grey scale targets of
-6 dB, +6 dB and high scatter relative to the background.
Limitations of Use
The 404GS LE is designed to be used to aid in the Quality Control testing and monitor-
ing of ultrasound instruments only. The 404GS LE is not to be used to make diagnostic
decisions.
4
Caring for your 404GS LE
Phantom comes ready to scan. Do not remove surface material.
Store your 404GSLE with cover closed securely.
Always attach the scanning surface cover and store the phantom out of direct sunlight
when it is not in use.
Store your 404GS LE at 35º–105ºF (2º–40ºC).
Freezing temperatures will damage the phantom and high temperatures will accelerate
desiccation.
Weigh your 404GS LE to monitor desiccation.
Weigh the phantom when you first receive it and then every 6 months. Record the
values on the data sheet.
Do not drop or damage the phantom.
Return the phantom for inspection and/or repair if it has been dropped or damaged.
Physical damage to the case will cause premature desiccation.
Gammex recommends annual servicing of your 404GS LE to ensure proper operation.
Our qualified service technicians will check for desiccation and provide any needed
rejuvenation, scanning/certification to original specifications, and repairs.
5
Scanning your 404GS LE
• Always place the phantom on a stable, level surface for scanning.
• The phantom comes ready to scan. Do not peel off the surface material.
• Use water or a generous amount of coupling gel to ensure good transmission.
Do not use mineral oil, baby oil or lanolin-based gels as a coupling medium.
Poor transmission is a result of insufficient coupling.
• Do not press the transducer into the scanning surface. This damages the
scanning surface and will shorten the life of the phantom. For curved transduc-
ers, use water or a thick gel layer.
• Clean the scanning surface immediately after use. Use a soft cloth or paper
towel and soap and water, if needed.
Caution:
Do not press the transducer
into the scanning surface.
6
A Guided Tour of your 404GS LE
The 404GS LE Precision Small Parts Phantom is an instrument for measuring the
image quality of small parts and intra-cavity ultrasound scanning systems. The tissue
mimicking gel in the 404GS LE is ultrasonically similar to human tissue. This allows the
use of normal scanner control settings and ensures that the performance measured
with the phantom closely approximates the scanner’s performance in a clinical exam-
ination.
Scanning is the best way to familiarize yourself with the features and functions of the
404GS LE. A guided tour of the phantom is provided on the following pages.
7
Evaluating the Phantom
Remember
A 4.5 MHz probe will provide a good overall view of the phantom for this demonstration.
1. Turn the handle out of the way and slide the cover off the phantom.
2. To couple with water, fill the dam with distilled water. For a better image quality,
use gel.
3. 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.
• 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 not use mineral oil, baby oil, or lanolin-based gels as a coupling
medium.
8
4. 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-uniformities and artifacts, making them easier to detect. Scanning an area
without targets is a good way to test for image uniformity.
Decrease gain controls to highlight pin targets.
5. 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 5 mm spacing while the horizon-
tal pins have 10 mm spacing.
Use the pin targets to determine vertical distance accuracy and horizontal dis-
tance accuracy. Note that the highest dead zone pin you can see should be the
point of reference not the scanning surface.
6. Freeze an image of the resolution target group at 1 cm. Examine the horizontal
row of pins at the top of the target group. The pins that are closest together
without touching indicates the scanner’s lateral resolution.
9
Repeat this procedure with the other resolution target groups. Notice how lateral reso-
lution is narrowest in the focal zone. For a transducer whose focal zone is in the area
between the resolution targets, an alternate test can be performed.
Freeze an image of the vertical pin targets. Use the electronic calipers to measure the
horizontal width of the pin targets in the near, mid and far fields of the image.
Notice how the pin targets are narrowest in the focal zone. The pin width demonstrates
the width of the ultrasound beam at that depth and approximates the lateral resolution
of the scanner.
7. Decrease the image depth and examine the resolution target group at 1 cm.
Notice how the images of the lower pin targets may begin to merge. The
smallest distance between two pins that can be clearly resolved with no vertical
overlap is called the scanner’s axial resolution.
10
Pin targets are resovled axially if an imaginary horizontal line can be drawn
between the targets without touching either target. The targets on the left are not
resolved. The targets on the right are resolved.
Examine the other resolution target groups and compare the resolution at various
depths. Axial resolution may change with depth.
8. Scan the nearest cystic target group. Each target should be round with a clean
black appearance and well defined edges. Bright specular echoes at the top and
bottom of the targets are normal.
Measure the dimensions of the 4 mm cystic target to check the image geometry.
Use the calipers to measure from top to bottom and side to side. Repeat with the
other cystic target groups as part of the cyst imaging test.
9. Decrease image depth to the minimum and examine the dead zone target group.
The dead zone targets can be used to measure lateral resolution in the extreme
near field of the transducer.
Note: The highest dead zone pin you can see should be the point of
reference for all measurements – not the scanning surface.
10. Scan the four grey scale targets and observe the difference in their grey levels.
Adjust the gain control and observe how this affects the brightness of the targets.
Unresolved Resolved
Table of contents
Other Gammex Measuring Instrument manuals
