Acoustic Output - GE Versana Essential Technical Publication

Safety

Acoustic Output

CAUTION
Acoustic Output Display Specifications
Thermal Index
4-32
Allowing the machine to transmit acoustic output with the probe
not in use (or in its holder) can cause the transducer to build up
heat. Always lower the acoustic power or freeze the image
when not in use.
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 user 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 and increments in steps of 0.2.
Always be aware of the acoustic output level by observing the
Acoustic Output Display. In addition, become thoroughly familiar
with the Acoustic Output Display and equipment controls
affecting output.
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.
–
Versana Essential
5759238-100 English Rev. 2
User Guide