Table of Contents
Advertisement
U60 Diagnostic Ultrasound System User Manual
C6152UB
L552UB
Notes
A2.5: 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, 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 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 and beam width.
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.
A2.6: 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.
± 22.91%
± 22.91%
Uncertainties based on
the
intensity
uncertainties.
- 201
Ultrasound Intensity and Safety
± 0.2%
± 0.2%
Uncertainties
based
on the oscilloscope.
-
± 11.68%
± 11.68%
Uncertainties based on
the pressure and center
frequency.
Advertisement
Table of Contents
