Siemens ACUSON Freestyle - Page 34

2-14 ACUSON Freestyle User Manual
Safety and Care
Denition of Acoustic Terms
Term Denition
ISPTA.3 Intensity, spatial-peak temporal average: The value of the temporal-
average intensity at the point in the acoustic eld where the temporal-
average intensity is a maximum, or is a local maximum within a specied
region. Units: milliwatts/cm
2
.
TI Thermal Index: A quantity related to calculated or estimated temperature
rise under certain dened assumptions. The thermal index is the ratio
of total acoustic power to the acoustic power required to raise tissue
temperature by 1º C under dened assumptions. C: Cranial. S: Soft
tissue. B: Bone.
MI Mechanical Index: The spatial-peak value of the peak rarefactional
pressure, derated by 0.3 dB/cm-MHz at each point along the beam axis,
divided by the square root of the center frequency.
IPA.3@MImax Intensity, pulse average at the maximum MI: The ratio of the pulse
intensity integral to the pulse duration at the maximum MI. Units W/cm
2
.
Acoustic Output Global Maximum Values: B-Mode
TRACK 3 Summary (for systems with no probes having global maximum index values
exceeding 1.0)
Transducer
Model ISPTA.3 TI Type TI Value MI IPA.3@MImax
L8-3 3.58 mW/cm
2
TIC 0.09 0.76 92.7 W/cm
2
L13-5 1.15 mW/cm
2
TIS 0.02 0.33 31.74 W/cm
2
C5-2 4.53 mW/cm
2
TIC 0.15 0.76 67.21 W/cm
2
Acoustic Output Global Maximum Values: Color Doppler
TRACK 3 Summary (for systems with no probes having global maximum index values
exceeding 1.0)
Transducer
Model ISPTA.3 TI Type TI Value MI IPA.3@MImax
L8-3 33.02 mW/cm
2
TIC 0.72 0.76 132.41 W/cm
2
L13-5 54.49 mW/cm
2
TIC 0.86 0.38 86.44 W/cm
2
C5-2 19.09 mW/cm
2
TIC 0.88 0.76 75.18 W/cm
2