Acclarix LX9 Series Diagnostic Ultrasound System User Manual
Ultrasound Intensity and Safety
B.4.4 Acoustic Power Default Settings
The ultrasound system allows direct control of acoustic power by the Power paddle key on the touch
screen. The range can be adjusted is 10% to 100%. The higher the acoustic power number, the
greater the acoustic output.
The factory default settings of acoustic power is 100%. The default settings can be reconfigured by
the operator through the Acoustic Power item on Utilities->Set up->Preset page. The ultrasound
system switch to default settings upon power up, new patient, new exam or new transducer.
B.4.5 Limits of Acoustic Output
In accordance with the FDA Track 3 requirements, the maximum acoustic output level from any
transducer in any operating mode is expected to fall below the limits as listed below.
FDA Maximum Acoustic Output Limits for Track 3(Attenuated Values)
B.5 Operator Control Features
The possibility of producing mechanical/thermal biological effects can be influenced by three kinds of
controls: Direct Controls, Indirect Controls, and Receiver Controls. The qualified operator may use the
system controls to minimize the ultrasound output while acquiring necessary clinical information.
Direct Controls
The acoustic output of the system can be controlled directly through the level of voltage transmitted. In
this case, the maximum acoustic output never exceeds the limits in any mode of operation.
Indirect Controls
The acoustic output of the system can be controlled indirectly through many imaging parameters,
including imaging modes, field of view, line density, probe frequency, focus number/position, depth
and pulse repetition frequency (PRF).
The imaging mode determines whether the ultrasound beam is scanning or non-scanning. Thermal
bioeffect is closely associated with B, M, PW and Color mode.
Acoustic attenuation of tissue is directly connected to probe frequency.
The focus number/position is related to active aperture of probe, beam width and frame rate.
The higher PRF (pulse repetition frequency), the more output pulses occur over a period of time.
Receiver Controls
The receiver controls (such as gain, TGC, dynamic range and image processing), which are used to
improve image quality, have no effect on acoustic output. Thus these controls should be optimized
before increasing acoustic output.
B.6 Prudent Use Statement
Although no confirmed bioeffects on patients caused by exposure from present diagnostic ultrasound
equipment have ever been reported, the potential exists that such bioeffects may be identified in the
future. Therefore, the ultrasound should be used prudently. High levels of acoustic output and long
exposure time should be avoided while acquiring necessary clinical information.
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