Output Display - Philips EPIQ 7 User Manual

Safety Biological Safety
An Example of Applying the ALARA Principle
An ultrasound scan of a patient's liver begins with selecting the appropriate transducer
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 adequate 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 sample volume over
the vessel. Before increasing output, adjust velocity range or scale and Doppler 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; and optimize the image by 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 time. Diagnostic ultrasound is an
important tool in medicine, and like any tool, it should be used efficiently and effectively.

Output Display

The system output display comprises two basic indices: a mechanical index and a thermal index.
The mechanical index is continuously displayed over the range of 0.0 to 1.9, in increments of
0.1 for all applications except contrast, where the minimum increment is 0.01.
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