Acoustic Output 15-3
15.4.2 MI/TI Display
TI and MI values are displayed in the top part of the screen in real time by preset (see chapter
“12.1 System Preset” for details.) The operator should monitor these index values during
examinations and ensure that exposure time and output values are maintained at the minimum
amounts required for effective diagnosis.
If a value of MI or TI exceeds 1.0, the ALARA principle must be practiced.
The display precision is 0.1.
Display accuracy of MI is ≤14.7%, and TI is ≤28.5%.
15.5 Acoustic Power Setting
Acoustic power adjustment
Use the [A.power(%)] on the image menu to adjust the acoustic power percentage. Its value is
displayed on the corresponding item, as well as 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 acoustic power setting
Selection of diagnostic applications is the most important factor in 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.
Within this system, imaging setups can be created using the ultrasound output set by you.
Once you set the preset settings, the system's default setting values may be changed
and invalid. The user is responsible for any change to the default settings.
Adjusting range
Initial power: 3.2% to 100%*
Definition of 100%: the maximum acoustic power of a probe determined by the increase in
probe surface temperature in the selected mode and the acoustic power restrictions specified
by the FDA.
Default settings of the acoustic power value refer to the best image quality for the probe. The
larger the acoustic power value, the better the image quality.
This system automatically returns to the settings whenever changes are made to the
values (when you turn on the power, switch between probes, tap [End] in the bottom-
left corner of the operating panel, or select [Save] or [Cancel] in the preset menu). In
the factory default settings, the Acoustic Output is limited to below 100%. Following
the ALARA restriction, you are allowed to increase the acoustic power under FDA
510(k) Guidance-Track 3 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: 2015, FDA 510(K) GUIDANCE, IEC 62359: 2017, Ultrasonics-Field
characterization-Test methods for the deter mination of thermal and mechanical indices related
to medical diagnostic ultrasonic fields.