Testing Of Measurement Tolerances; Conducting Tests; Result Judgement - Hitachi UST-9133 Instruction Manual

MN1-5241 Rev. 21

8-2. Testing of measurement tolerances

Perform the measurements specified below using an ultrasonic phantom* at least once per year. The test record
should be stored for future reference.
• Sensitivity
• Resolution
Remarks
Make a copy of the Measurement accuracy inspection data sheet provided in the instruction manual for
the ultrasound diagnostic instrument. Use the sheet as a test record.
* The ultrasonic phantom is made of a substance which is similar to human tissue in terms of its response to
ultrasonic waves.
Regions with different textures and targets spaced at preset intervals are embedded in the phantom. Some
phantoms contain a mechanism for Doppler measurement. The phantom is used to check the performance
of the probe and ultrasonic diagnostic instrument, as well as to adjust the image settings.

8-2-1. Conducting tests

Some types of ultrasonic phantoms have targets with narrow gaps between them for confirming the
resolution.
This enables you to check the level of detail that images can be viewed on the display. For phantoms
with no targets, the resolution determines the fineness of the displayed textures. The sensitivity can be
determined by examining the luminance of ultrasonic images. Other factors that affect the resolution
include the type of connected probe, gain, focus and recording instrument. The specific testing conditions
must be recorded in detail to enable proper comparison at the next inspection.

8-2-2. Result judgement

Compare the currently-obtained value with the value recorded at the last test. If there is a significant
difference between the two values, the current value is considered to be abnormal.
It is important to note that the resolution varies depending on the type of ultrasonic phantom and
phantoms generally deteriorate over time.
Caution
Do not use a probe or ultrasound diagnostic instrument where a problem has been found.
This can result in an incorrect diagnosis. Contact one of our offices and/or distributor's offices listed
on the back cover.
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