Acoustic Output - GE Venue 50 Basic User Manual

Introduction/Safety

Acoustic Output

Acoustic Output Display Specifications
Thermal Index
Mechanical Index
1-30
Located on the upper right section of the system display monitor,
the acoustic output display provides the operator with real-time
indication of acoustic levels being generated by the system. See
the Acoustic Output chapter in the Advanced Reference Manual
for more information. This display is based on NEMA/AIUM
standards for real-time display of thermal and mechanic
acoustic output indices on diagnostic ultrasound equipment.
The display consists of three parts: Thermal Index (TI),
Mechanical Index (MI), and a relative Acoustic Output (AO)
value. Although not part of the NEMA/AIUM standard, the AO
value informs the operator of where the system is operating
within the range of available output.
The TI and MI are displayed at all times. The TI and MI display
starts at a value of 0.0 and increments in steps of 0.1.
Depending on the examination and type of tissue involved, the
TI parameter will be one of three types:
• Soft Tissue Thermal Index (TIS). Used when imaging soft
tissue only, it provides an estimate of potential temperature
increase in soft tissue.
• Bone Thermal Index (TIB). Used when bone is near the
focus of the image as in the third trimester OB examination,
it provides an estimate of potential temperature increase in
the bone or adjacent soft tissue.
• Cranial Bone Thermal Index (TIC). Used when bone is
near the skin surface as in transcranial examination, it
provides an estimate of potential temperature increase in
the bone or adjacent soft tissue.
MI recognizes the importance of non-thermal processes,
cavitation in particular, and the Index is an attempt to indicate
the probability that they might occur within the tissue.
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Venue 50 Basic User Manual
Direction 5446729-100 English Rev. 7