Safety
HD11 XE Getting Started
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Receiver Controls
Receiver controls are used by the operator to improve image quality. These con-
trols have no effect on output. Receiver controls only affect how the ultrasound
echo is received. These controls include gain, TGC, dynamic range, and image
processing. The important thing to remember, relative to output, is that receiver
controls should be optimized before output is increased. For example: before
increasing output, optimize gain to improve image quality.
An Example of Applying ALARA
An ultrasound scan of a patient’s liver begins with selecting the appropriate trans-
ducer frequency. After selecting the transducer and the application, which are
based on patient anatomy, adjustments to output power should be made to
ensure that the lowest possible setting is used to acquire an image. After the
image is acquired, adjusting the focus of the transducer, and then increasing the
receiver gain to produce a uniform representation of the tissue follows. If an ade-
quate image can be obtained with the increase in gain, then a decrease in output
should be made. Only after making these adjustments should you increase output
to the next level.
Having acquired the 2D display of the liver, Color can be used to localize blood
flow. As with the 2D image display, gain and image processing controls must be
optimized before increasing output.
Having localized the blood flow, use the Doppler controls to position the gate
over the vessel. Before increasing output, adjust velocity range or scale and Dop-
pler gain to obtain an optimal Doppler trace. Only if maximum Doppler gain does
not create an acceptable image do you increase output.
In summary: select the correct transducer frequency and application for the job;
start with a low output level; optimize the image using focus, receiver gain, and
other imaging controls; if the image is not diagnostically useful at this point, then
increase output.
Additional Considerations
Ensure that scanning time is kept to a minimum, and ensure that only medically
required scanning is performed. Never compromise quality by rushing through an
exam. A poor exam may require a follow-up, which ultimately increases exposure
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