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 thermal index further consists of the following indices: soft
tissue (TIS), bone (TIB), and cranial bone (TIC). One of these three thermal
indices will be displayed at all times. Which one depends upon the system preset
or user choice, depending upon the application at hand.
The mechanical index is continuously displayed over the range of 0.0 to 1.9, in
increments of 0.1.
The thermal index comprises three indices, and only one of these is displayed
at any one time. Each transducer application has a default selection that is
appropriate for that combination. The TIB, TIS, or TIC is continuously displayed
over the range of 0.0 to maximum output, based on the transducer and
application, in increments of 0.1. For the location of the output display, see
"Imaging Display" on page 159.
The application-specific nature of the default setting is also an important factor
of index behavior. A default setting is a system control state that is preset by
the manufacturer or the operator. The system has default index settings for the
transducer application. The default settings are invoked automatically by the
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Safety
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