User's Manual

Rev.1.01
2022. 03.
41 / 57
Doc # : BN-SF-EOP-01
involved, TI could be one of three types.
 The soft tissue thermal index (TIs) : the user about the potential for heating
within soft homogeneous tissue.
 The bone thermal index (TIb) : the user about potential heating at or near
the focus after the ultrasound beam has passed through soft tissue or
fluid, such as the skeletal structure of a 2-3 month-old fetus.
 The cranial bone thermal index (TIc) : the user about the potential heating
of bone at or near the surface, for example, the cranial bone.
- Mechanical and Thermal Indices Display Precision and Accuracy
TI and MI values are displayed in real time on the screen. The operator should observe
these index values during examinations and ensure that exposure time and output
values are maintained at minimum amounts needed for effective diagnosis. The
Mechanical and Thermal Indices on the system are precise to 0.1 units.
6.2.3 Acoustic Power Statement
6.2.3.1 Acoustic Measurement Precision and Uncertainty
When estimating accuracy of displayed numerical values, many factors are considered:
- The Probe Changeability
- The system changeability
- Changeability and accuracy of measurement
- Possible operating conditions and testing numbers needed to obtain displayed
result accuracy of the diagnostic system
- Whether the display accuracy depends on specific system combination, mode
combination, probe component and launch mode combination, or all of above
- Algorithm accuracy of the system software used to calculate the MI/TI
- Approximation engineering method used in real time computation
6.2.3.2 Differences between Actual and Displayed MI and TI
For many assumptions used in the process of measurement and calculation, they
actually are conservative. For most organizations path, high estimate is made in the
measurement and calculation process of tissue exposure intensity. For example,
using attenuation coefficient 0.3 ㏈㎝
-1
㎒
-1
much lower than the actual human tissue