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Summary of Contents for Gammex 404GS LE
- Page 1 404GS LE Precision Small Parts Grey Scale Phantom User’s Guide Gammex...
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Page 2: Table Of Contents
Table of Contents Introduction..........................3 Caring for your 404GS LE.......................4 Scanning your 404GS LE ....................5 A Guided Tour of your 404GS LE.....................6 Evaluating the Phantom......................7 Target Specifications......................12 Cystic Targets........................12 Grey Scale Targets........................12 Pin Target..........................12 Resolution Target Group.......................12 Phantom Specifications.....................14 Physical Specification......................14 Tissue Mimicking Background Material................14 Low Scatter (Anechoic) Cysts....................14 Grey Scale Targets........................14... -
Page 3: Introduction
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. -
Page 4: Caring For Your 404Gs Le
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... -
Page 5: Scanning Your 404Gs Le
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. -
Page 6: A Guided Tour Of Your 404Gs Le
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. -
Page 7: Evaluating The Phantom
Evaluating the Phantom Remember • 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. - Page 8 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.
- Page 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.
- Page 10 Unresolved Resolved 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.
- Page 11 Notice how noise in the anechoic target becomes apparent as the gain increases. If your system has image “post-processing” capabilities, observe how the contrast between targets changes with different settings. Adjust the gain control to the lowest noise level. This is the point at which you eliminate noise in the anechoic cyst (lower the gain until it just disappears).
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Page 12: Target Specifications
Target Specifications Cystic Targets Diameters......................1, 2, 4 and 7 mm Placement....................1, 3, 3.5 and 6 cm deep Grey Scale Targets Diameter..........................7 mm Placement........................3 cm deep Pin Targets Diameter...........................0.1 mm Vertical spacing..................5 mm at 1–9 cm deep Horizontal spacing................10 mm at 1 and 5 cm deep Resolution Target Groups ......................1, 3.5 and 6 cm deep All acoustic measurements made at 4.5 MHz, 22ºC. -
Page 14: Phantom Specifications
Phantom Specifications Physical Specifications Weight..................Approx. 1.75 kg (3 lbs. 13 oz.) Dimensions...................17 x 8.25 x 15.875 cm ....................(6.75 x 3.25 x 6.25 in.) Scanning surface..................Composite film Case material....................ABS plastic Pin target material................Nylon monofilament Tissue Mimicking Background Material Water-based gel with appearance of human tissue. Speed of sound....................1540±10 m/s Temperature dependence of speed of sound............1.5 m/s/ºC Attenuation coefficient..............0.7±0.05 dB/cm/MHz... -
Page 15: Harmonic Imaging
Recently, we have developed the capacity to measure the value of B/A for the tissue-mimicking materials in Gammex phantoms and have found it to lie in the range for human soft tissue, meaning B/A is between 6 and 7 _______________________________________ Gong, X. - Page 16 Grey Scale Applications Metastases are sometimes slightly hyperechoic or hypoechoic compared with the sur- rounding tissue. If the scanner is not measuring grey levels accurately, the metastases may not be detected. The Quantitative Measurement ensures that the grey level signal is measured consistently.
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Page 17: System Linearity
System Linearity Ultrasound systems use special processing circuits to translate the amplitude of echoes into brightness levels on the video monitor. These circuits use mathematical functions that often produce an S-shaped curve when graphed. As shown in the figure below, each echo level produces a corresponding brightness level on the monitor. - Page 18 Changes in the shape of the S-curve result in different brightness levels for the same echo levels. Notice how the positions of the original brightness levels B – , B o and B + have moved to B – , B o and B + Changes in the system response can be identified by measuring the average pixel value of the grey scale targets and the background material as displayed on the video...
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Page 19: Quantitative Measurement
Quantitative Measurement A target’s brightness level can be most accurately measured using electronic methods. The user defines a region of interest and the scanner determines the average pixel value. To reduce the effect of speckle and small variations in the targets, several measurements are taken and averaged. -
Page 20: Qualitative Measurement
Measure and record the echo level of the background material directly beside the anechoic target. Use as close to the same ROI as the target as possible. Unfreeze the image. Perform this process three times and record the average echo level for each grey scale target and for the background material on the data sheet. -
Page 21: Phantom Desiccation
It is suggested that the phantom be sent in for rejuve- nation once it has lost 10-15 grams of its original weight. If the phantom has lost more than 20 grams, Gammex cannot guarantee that the phantom will be able to rejuvenate successfully. -
Page 22: Product Warranty
THERE ARE NO EXPRESS OR IMPLIED WARRANTIES WHICH EXTEND BEYOND THE WARRANTIES SET FORTH ABOVE, SELLER MAKES NO WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE WITH RESPECT TO THE PRODUCTS OR ANY PARTS THEREOF. © 2003, 2013 GAMMEX 006288-00-09 Your warranty may be registered at http://www.gammex.com/warranty.asp... -
Page 23: Sales And Service
Sales and Service GAMMEX is committed to satisfying our customer’s needs. If you have any questions, comments, or suggestions regarding our products and service, please call or fax us. Sales Department hours are Monday through Friday, 7:30 am to 5:00 pm Central Time. - Page 24 Notes:...
- Page 25 Gammex, Inc. 7600 Discovery Dr. Middleton, WI 53562 USA 1 800 GAMMEX 1 (426-6391) 1 608 828 7000 Fax: 1 608 828 7500 www.gammex.com e-mail: sales@gammex.com Gammex-RMI LTD Broadway Business Centre 32A Stoney Street Nottingham NG1 1LL United Kingdom +44 0115 9247188 Fax: +44 0115-9247189 e-mail: uksales@gammex.com...
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