S2/S2BW
Digital Color Doppler Ultrasound System
7.
Do not use endo-cavity probes if there is noticeable self heating of the probe when operating in the air.
Although applicable to any probe, take particular care during trans-vaginal exams during the first eight
weeks of gestation.
8.
Take particular care to reduce output and minimize exposure time of an embryo or fetus when the
temperature of the mother is already elevated.
9. Take particular care to reduce the risk of thermal hazard during diagnostic ultrasound when exposing:
an embryo less than eight weeks after gestation; or the head, brain or spine of any fetus or neonate.
10.
Operators should continually monitor the on-screen thermal index (TI) and mechanical index (MI) values
and use control settings that keep these settings as low as possible while still achieving diagnostically
useful results.
In obstetric examinations, TIS (soft tissue thermal index) should be monitored during scans carried out
in the first eight weeks after gestation, and TIB (bone thermal index) thereafter. In applications where
the probe is very close to bone (e.g. trans-cranial applications), TIC (cranial thermal index) should be
monitored.
MI> 0.3
There is a possibility of minor damage to neonatal lung
or intestine. If such exposure is necessary, reduce the
exposure time as much as possible.
MI> 0.7
There is a risk of cavitation if an ultrasound contrast
agent containing gas micro-spheres is being used.
There is a theoretical risk of cavitation without the pres-
ence of ultrasound contrast agents. The risk increases
with MI values above this threshold.
TI> 0.7
The overall exposure time of an embryo or fetus should
be restricted in accordance with Table 2.1 below as a
reference.
TI Maximum exposure time (minutes)
0.7 60
1.0 30
1.5 15
2.0 4
2.5 1
Table 2.1: Maximum recommended exposure times for an embryo or fetus
11.
Non-diagnostic use of ultrasound equipment is not generally recommended. Examples of non-diagnostic
uses of ultrasound equipment include repeated scans for operator training, equipment demonstration
using normal subjects, and the production of souvenir pictures or videos of a fetus.
For equipment of which the safety indices are displayed over their full range of values, the TI should
always be less than 0.5 and the MI should always be less than 0.3. Avoid frequent repeated exposure
of any subject.
Scans in the first trimester of pregnancy should not be carried out for the sole purpose of producing
souvenir videos or photographs, nor should their production involve increasing the exposure levels or
extending the scan times beyond those needed for clinical purposes.
12.
Diagnostic ultrasound has the potential for both false positive and false negative results. Misdiagnosis
is far more dangerous than any effect that might result from the ultrasound exposure. Therefore,
diagnostic ultrasound should be performed only by those with sufficient training and education.
P/N: 4710.00149A01
2-4
To Next Page
Loading...
Need help?
General
