A2.4: Ti (Thermal Index) - EDAN DUS 60 User Manual

DUS 60 Digital Ultrasonic Diagnostic Imaging System User Manual
Acoustic Output Reporting Table
Transducer Model: L743UA
Index Label MI
Global Maximum Index Value 0.4043
P MPa 0.9634
r.3
W mW
0
Min
of[W (z1),(mW)
.3
I (z1)]
ta.3
Associated
Z (cm)
1
Acoustic
Z (cm)
bp
Parameters
Z (cm) 2.15
sp
deq(Z ) (cm)
sp
f (MHz) 5.6782
c
Dim of X(cm)
Aaprt
Y (cm)
PD (usec) 1.5134
PRF (Hz) 6361
P @PII (MPa) 2.35
r max
Other
d @PII (cm) 0.0076
eq max
Information
Focal FL (cm)
x
Length
Fl (cm)
y
2
I @MI (W/cm ) 0.1433
pa.3 max
Control
Control1
Conditions
The device is not intended for ophthalmic use. Do not use it for examining ophthalmic
vessels, or any other procedures which may cause the ultrasound beam to pass through
the eye.
Ultrasound Intensity and Safety
Operating Model: PW Mode
TIS TIB
Non-Scan
Scan Non-scan
A ≤1 A >1
aprt aprt
0.9339 3.0125
35.2 35.2
2.15
0.0076
5.6782 5.6782
1.344 1.344
0.6 0.6
0.0076
0.5274
4.635
AP=15; Frequency=6.0MHz;
Depth=78mm; Focus=35mm;
WARNING
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DUS 60 Digital Ultrasonic Diagnostic Imaging System User Manual

A2.4: TI (Thermal Index)

TI is determined by the ratio of the total acoustic power to the acoustic power required to raise
the tissue temperature by 1degree Celsius. Once there is a situation that a TI value is greater than
TIC
1.0, the TI value will be displayed in the upper part of the screen.
The adverse biological effects of ultrasound on tissue appear to be, in contrary to what is assumed
0.8505
for X-ray, threshold effects. When tissue is repeatedly exposed to ultrasound, with intervals in
between, there will likely be no cumulative biological effect. If a certain threshold has been
35.2
passed, biological effects may occur. A temperature rise from 37 °C to 41 °C is acceptable for
quite a long time, whereas a temperature rise to 45 °C may not be acceptable. The same counts
for cavitation in that, below a certain level, there will be no cavitation and hence no biological
effect.
A prudent starting-point for each examination would be first to set the machine for the lowest
index setting and then modify from this level until a satisfactory image or Doppler signal is
obtained, keeping track of the TI; and second, the exposure time, during one examination, should
be kept as short as possible. A safety guideline on this should be included.
5.6782
1.344
0.6
0.5274
4.635
Ultrasound Intensity and Safety
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