Safety Information
T3300 Diagnostic Ultrasound System | 17 | B00601-010 4/10/17
2.6.1 Heating
Elevating tissue temperature during obstetrical examinations creates medical concerns. At the
embryo development stage, the rise in temperature and the length of time exposed to heat combine
to determine potential detrimental effects. Exercise caution, particularly during Color imaging exams.
The Thermal Index (TI) provides a statistical estimate of the potential temperature elevation (in
centigrade) of tissue temperature. Two forms of TI are available: TIS, for soft tissue exposures; and
TIB, for instances when bone lies near the beam focus.
2.6.2 Cavitation
Cavitation may occur when sound passes through an area that contains a cavity, such as a gas
bubble or air pocket (in the lung or intestine, for example). During the process of cavitation, the
sound wave may cause the bubble to contract or resonate. This oscillation may cause the bubbles
to explode and damage the tissue. The Mechanical Index (MI) has been created to help operators
accurately evaluate the likelihood of cavitation and the related adverse effects.
2.6.3 Safe Scanning Guideline
• Ultrasound should only be used for medical diagnosis and only by trained medical personnel.
WARNINGS
• Diagnostic ultrasound procedures should be done only by personnel fully trained in the
use of the system, in the interpretation of the results and images, and in the safe use of
ultrasound (including education as to potential hazards).
• Operators should understand the likely influence of the machine controls, the operating
mode (e.g. B-mode, Color or Spectral Doppler) and the transducer frequency on thermal
and cavitation hazards.
• Use a low output power default setting for each new patient. Output should only be increased
during the examination if penetration is still required to achieve a satisfactory result, and after the
Gain control has been adjusted to its maximum value.
• Maintain the shortest examination time necessary to produce a useful diagnostic result.
WARNINGS
• Take particular care to reduce output and minimize exposure time of an embryo or fetus
when the temperature of the mother is already elevated.
• 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.
• Although applicable to any transducer, take particular care during trans-vaginal exams
during the first eight weeks of gestation.
• During continuous operation, the system temperature may become too high. If the following
system message displays during a real-time scan, touch OK and the system displays frozen
imaging screen. To resume scanning, wait until the system cools down.
• 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)
System temperature is high. Please cease
the current scan for a few minutes.
OK
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