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Acoustic Output; Alara / Prudent Use - Siemens ACUSON Freestyle User Manual

Diagnostic ultrasound system.
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Acoustic Output

WARNING: Ultrasound procedures should be used for valid reasons, for the shortest
period of time, and at the lowest mechanical/thermal index setting necessary to produce
clinically acceptable images.
NOTE: For ultrasound systems distributed in the United States of America, refer to
the Medical Ultrasound Safety ultrasound education program brochure produced by
the AIUM that is shipped with the system. This document explains the interaction of
ultrasound and tissue, the possibilities and mechanisms of bioeffects, and it explains
the terms used to describe acoustic output.
The ultrasound energy, frequency levels, and scanning times employed by the
Freestyle have not been associated with harmful effects. Nevertheless, it is advisable to
minimize the patient's exposure to ultrasound energy. This prudent use can be accomplished
by following the
(As Low as Reasonably Achievable) Principle, and by operating the
system in a manner that reduces patient exposure to ultrasound energy. Acoustic Output
tables for the
Freestyle are provided below.
The acoustic output for the
accordance with the "Acoustic Output Measurement Standard for Diagnostic Ultrasound
Equipment" (NEMA UD2-2004), and the "Standard for Real-Time Display of Thermal and
Mechanical Acoustic Output Indices on Diagnostic Ultrasound Equipment" (NEMA UD3-2004.)

ALARA / Prudent Use

Prudent use of ultrasound requires that patient exposure to ultrasound energy be limited to the
lowest output for the shortest period of time needed to obtain acceptable diagnostic results.
Techniques include:
Keep exams as brief as possible, consistent with diagnostic requirements.
Select the appropriate transducer for the patient body type and exam type in order to
optimize imaging results.
Use overall gain or dynamic range or post processing settings, which have no effect on
output, to optimize the image and obtain diagnostic results.
In general, as shown in the Acoustic Output Tables, Color Flow Doppler mode will have
higher output levels than B-Mode (2D). Keep this in mind when scanning. New studies
default to B-Mode.
Freestyle User Manual
Freestyle has been measured and calculated in
Safety and Care


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