Cirs ATS539 - Testing Procedures; Uniformity Testing; Depth of Penetration Testing

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TESTING PROCEDURES
The following sections outline procedures for routine quality control tests with the
Model ATS539. It may be useful to refer to the target map, shown in the Specica-
tions section of page 14, when reviewing these procedures.
UNIFORMITY TESTING
Uniformity is dened as the ability of the machine to display echoes of the same
magnitude and depth with equal brightness on the display. This is a good test to
ensure all crystals within the transducer are functioning.
1. Apply coupling gel to the scanning surface or ll the water trough with tap water.
2. Position the transducer on the scanning surface in a region with a minimum
number of targets.
3. Adjust the instrument settings (gain, TGC, output, etc.) as for a “normal”
technique. Record these settings for use on subsequent testing.
4. Align the probe so that the targets are maximized.
5. Freeze the image and obtain a hard copy.
6. Observe the general appearance of the phantom. Note if all regions at the
same depth are displayed with the same intensity across the image.
7. Record your observations.
DEPTH OF PENETRATION TESTING
The ability of an imaging system to detect and display weak echoes from small ob-
jects located at specied depths (penetration) is referred to as sensitivity. Clinically,
weak reecting echoes are commonly produced from internal structures of organs.
Denition of these structures can be extremely important in the interpretation of the
ultrasound ndings. Sensitivity can be affected by the pulser/receiver section of the
system, the degree of focusing of the transducer, attenuation of the medium, depth
and shape (geometry) of the reecting object, and electromagnetic interference from
the local surroundings. Testing is performed as follows:
1. Place the phantom on a clean, at surface with #1 scanning surface positioned
for use
2. Apply an adequate amount of low viscosity gel or water to the scan surface. If
water is used, ll the scanning well slowly to avoid introduction of air bubbles.
3. Adjust the instrument settings (TGC, output, etc.) to establish baseline values
for "normal" scanning. If the bottom of the phantom is seen, lower the gain
settings until the bottom of the image goes entirely black. Record these settings
on the quality assurance record. These settings should be used for subsequent
testing.