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15

Evaluating the Doppler System

For the Doppler demonstration:

Use a 5 MHz transducer

Turn on the Doppler Mode

1.

Select a flow rate preset using Up/Down buttons. It takes a few seconds for the flow to 
reach the selected rate.

2.

Use a sector transducer to scan the blood vessel. Place the transducer so that the central 
acoustic axis of the color image is perpendicular to the axis of the vessel. This can be 
determined by visualizing the inner and outer surface of the vessel wall, both on the top and 
bottom.

3.

Examine the image. The “positive” color flow segment should mirror the “negative” color flow 
segment across the image of the vessel. Proper color balance demonstrates the scanner’s direc-
tional discrimination.

Summary of Contents for Optimizer

Page 1: ...Optimizer 1425A Ultrasound Image Analyzer for Doppler and Grey Scale Scanner User s Guide T 31 0 24 648 86 88 Nederland Belgi Belgique T 32 0 3 309 32 09 www gotoPEO com info gotoPEO com...

Page 2: ...ng 12 Grey Scale Applications 13 Charts and Graphs 13 Doppler Guided Tour 14 Evaluating the Doppler System 15 Doppler Quality Control Tests 17 Doppler Signal Sensitivity 17 Color Flow Sensitivity 17 F...

Page 3: ...ets for tests of depth of penetration axial and lateral resolution and electronic caliper accuracy in addition to the attenuation and scattering characteristics of human soft tissue Anechoic cystic ta...

Page 4: ...sical damage to the case will cause premature desiccation If your 1425A is not regularly in use step the 1425A through the constant and pulsatile flow settings for a period of 1 2 hours on a monthly b...

Page 5: ...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...

Page 6: ...g gel vessels and blood mimicking fluid are ultrasonically similar to human tissue This allows the use of normal scanner control settings and ensures that the performance measured with the phantom clo...

Page 7: ...phasizes 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 cali...

Page 8: ...he ultrasound beam at that depth and approximates the lateral resolution of the scanner M eas ur epi n wi dt h t o getl at er al r es ol ut i on Pi n t ar get sar e nar r owes ti n t he f ocalzone 6 D...

Page 9: ...well defined edges Bright specular echoes at the top and bottom of the targets are normal Unr es ol ved Res ol ved Measure the dimensions of the 4 mm cystic target to check the image geometry Use the...

Page 10: ...t for future grey scale measurements Freeze the image and visually evaluate the grey scale targets Match each target with a step on the grey bar in the image Make a hard copy and compare the hard copy...

Page 11: ...ed gel with appearance of human tissue Speed of sound 1540 10 m s Temperature dependence of speed of sound 1 5 m s C Attenuation coefficient 0 7 0 05 dB cm MHz 0 5 0 05 dB cm MHz Low Scatter Anechoic...

Page 12: ...uch attenuation as there would be if the higher frequency were used to generate the pulses at the transducer So higher frequency resolution occurs for greater depths within the subject than if convent...

Page 13: ...an air tight container will contribute greatly to long phantom life Properly storing your phantom will reduce the amount of moisture lost per year For instructions on how to properly store and take c...

Page 14: ...e quality control and comparison of ultrasound systems as well as teaching the principles of Doppler ultrasound 1 String phantoms are not physiological 7 String phantoms display a specular like reflec...

Page 15: ...can the blood vessel Place the transducer so that the central acoustic axis of the color image is perpendicular to the axis of the vessel This can be determined by visualizing the inner and outer surf...

Page 16: ...smallest opening Compare the displayed peak value on the scanner with the estimated peak value corresponding to the displayed flow on the control module to determine the accuracy of the maximum veloci...

Page 17: ...es out is the system s Doppler Signal Sensitivity 4 Repeat this test at a range of flow rates from low to high 5 Record the results on the Doppler QC Test Data Sheet Color Flow Sensitivity Similar to...

Page 18: ...ntom to constant flow mode 2 Set the scanner s color flow output power and color gain for maximum sensitivity without excessive noise 3 Toggle between color flow and B mode Observe whether the color f...

Page 19: ...volume flow rate depends on the velocity profile within the tube If the profile is assumed parabolic the maximum velocity inside the tube is 2x the average velocity If the flow is turbulent or has som...

Page 20: ...as In case of a parabolic velocity profile the axial velocity is We cannot assume that the flow of the fluid as it enters the 1425A system is laminar Therefore the entrance length can only be estimate...

Page 21: ...r analysis The location of the cursor in the phantom should be accurately repre sented on the B mode image Note A small gate size is preferred 1 Set the Doppler phantom to produce a constant flow 2 Sc...

Page 22: ...ckness 1 25 mm Positions Horizontal at 2 cm deep Diagonal 40 from 2 cm deep at wall Re 850 at max velocity L 10 5 cm at max velocity Flow Meter Type in line turbine Accuracy better than 1 5 F S The mi...

Page 23: ...1995 Quality Control and Acceptance Testing In W R Hendrick S D L Hykes D E Starchman Ed Ultrasound Physics and Instrumentation 3rd Edition pp 280 313 Mosby Yearbook 6 IEC 61685 2001 International Sta...

Page 24: ...iscovery of the defect and d which are found to be defective by Seller upon Seller s examination Buyer shall pay all trans portation charges Products manufactured by third parties must be returned to...

Page 25: ...epartment hours are Monday through Friday 7 30 am to 5 00 pm Central Time 1 800 GAMMEX 1 426 6391 1 608 828 7000 1 608 828 7500 Fax e mail sales gammex com Service Department hours are Monday through...

Page 26: ...26 Notes...

Page 27: ...27 Notes...

Page 28: ...I LTD Broadway Business Centre 32A Stoney Street Nottingham NG1 1LL United Kingdom 44 0115 9247188 Fax 44 0115 9247189 e mail uksales gammex com Gammex RMI GMBH Bergstrasse 2 35398 Giessen Germany 49...

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