Acoustic Output 14-3
⚫ TIC: Thermal index for applications, such as pediatric and adult cranial applications,
in which the ultrasound beam passes through bone near the beam entrance into the
body.
WFUMB (World Federation for Ultrasound in Medicine and Biology) guidelines: state
that temperature increase of 4 degree C for 5 min or more should be considered as
potentially hazardous to embryonic and fetal tissue.
The smaller the MI/TI values, the lower the bioeffects.
14.4.2 MI/TI Display
TI and MI values are displayed in real time in the upper part of the screen. The operator
should monitor these index values during examinations and ensure that exposure time and
output values are maintained at the minimum amounts needed for effective diagnosis.
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] in 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
* 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.
Default settings of acoustic power value refer to the best image quality of the probe.
The larger the acoustic power value, the better the image quality.
In the DP-20/DP-25 products, to obtain optimum images for applications under the
requirements of safety and ALARA principle, we set acoustic power default values in
factory to be maximum 97% in OB1, OB2/3, Fetal-Cardiac exam modes and other
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