Shenzhen Mindray Bio-Medical Electronics Co., Ltd. DC-N2, Руководство оператора

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Acoustic Output 14-3
NOTE: If there is a value of MI or TI exceeds 1.0, you must be careful to practice the
ALARA principle.
The display precision is 0.1.
Display accuracy of MI is ±28.5%, TI is±38.7%
14.5 Acoustic Power Setting
„
Acoustic power adjustment
Click [A. power] on the menu to adjust the acoustic power percentage, and the value is
displayed on the screen. The greater the acoustic power percentage, the greater the current
acoustic output.
When the image is frozen, the system stops transmitting acoustic power.
„
Default setting of acoustic power
Selection of diagnostic applications is the most important factor for controlling ultrasound
output.
The permissible level of intensity of ultrasound differs depending on the region of interest. For
fetal examinations, in particular, much care must be exercised.
In this system, imaging setups can be created using the ultrasound output set by you. At this
time, the default function is disabled. It is the user’s responsibility for any change to the
default settings.
Default choices
Initial power 7% to 100%*
* Definition of 100%:
The maximum acoustic power of a transducer determined by the increase in transducer
surface temperature in the selected mode and the acoustic power restrictions specified
by the FDA.
NOTE:
This system automatically returns to the settings whenever changes are made to
the values (when you turn on the power, switch between transducers, press [End
Exam], or select [Save] in the Setup menu). In the factory default settings, the
Acoustic Output is limited below 100%. Following the ALARA restriction, you are
allowed to increase the acoustic power under FDA 510(k) Guidance-Track3 limits
and to set it in the image preset screen.
The acoustic output of the system has been measured and calculated in accordance with
IEC60601-2-37: 2005, FDA 510(K) GUIDANCE, Acoustic Output Measurement Standard for
Diagnostic Ultrasound Equipment (NEMA UD-2 2004) and the “Standard for Real-Time
Display of Thermal and Mechanical Indices on Diagnostic Ultrasound Equipment (AIUM and
NEMA UD-3 2004).
14.6 Acoustic Power Control
The qualified operator may use the system controls to limit the ultrasound output and to adjust
the quality of the images. There are three categories of system controls relative to output.
They are controls that have direct effect on the output, controls that indirectly control output
and controls that are receiver controls.
„
Direct Controls
It is possible to control, if necessary, the acoustic output with the menu control. In this case,
the maximum value of the acoustic output never exceeds an MI of 1.9, TI of 6 and an I
SPTA.3
of
720 mW/cm
2
in any mode of operation.