ATS 535-H Handmatig - Pagina 7

Blader online of download pdf Handmatig voor {categorie_naam} ATS 535-H. ATS 535-H 12 pagina's. Basic quality assurance phantom

5. Using the electronic calipers or the timing markers measure the greatest distance that can be

clearly imaged between line targets.

6. Document the measurement obtained on the quality assurance record.

Results

Vertical Spacing: 1.0 cm center to center ± 0.1 mm

If a discrepancy occurs which is greater than 1.0 mm, corrective action should be considered by the

individual Ultrasound Department.

HORIZONTAL MEASUREMENT CALIBRATION

Description and Reason For Testing

Horizontal distance measurements are obtained perpendicular to the axis of the sound beam. Proper

diagnosis is dependent upon the accurate representation of the size and volume of a structure being

examined. Most imaging systems use distance markers and/or electronic calipers to obtain these

measurements. The phantom is scanned and a distance measurement obtained. The resulting

measurement is then compared to the known distance in the phantom. The accuracy of the horizontal

distance measurements is dependent upon the integrity of the transducer, the output intensity and the

resolution of the imaging system.

Testing Procedure

Note: The Model 535-H Basic QA phantom provides two scanning surfaces used to evaluate horizontal

measurement calibration. Linear array scanning systems should use #1 scanning surfaces. Sector

scanning systems should use #3 scanning surfaces.

1. Place the phantom on a clean, flat surface.

2. Apply an adequate amount of low viscosity gel or water to the scan surface. If water is used,

fill the scanning well slowly to avoid introduction of air bubbles.

3. Adjust the instrument settings (TGC, output, etc.) to establish baseline values for "normal"

liver scanning. If the bottom of the phantom is seen, adjust the gain settings until the image

goes entirely black. Record these settings on the quality assurance record. These settings

should be used for subsequent testing.

4. Position the transducer over the horizontal group of line targets until a clear image is obtained.

Freeze the image.

5. Using the electronic calipers or the timing markers measure the greatest distance that can be

clearly imaged between line targets displayed.

6. Note: Some sector scanners have distance markers on the outside edges of the sector image

with no other indicators available. Hand-held calipers must be used for distance

measurements within the image on the monitor.

7. Document all of the measurements on the quality assurance record.

Results

Interval Spacing:

Depths:

If a discrepancy occurs which is greater than 2 mm, corrective action should be considered by the

individual Ultrasound Department.

2 cm ± 1 mm

5 cm ±.1 mm (Scan surface #1)

5 cm ±.1 mm (Scan surface #3)