User's Manual

Table Of Contents
InnoSight Ultrasound System
Understanding the MI/TI Display 
2 enin
24
P6992-4, EN, 16/12/6
Mode / Transducer
C6-2 Curved Linear
Array 2-6 MHz
L12-4 Linear Array
4-12 MHz
S4-2 Phased Array
64 elements
2-4 MHz
C9-4v Micro
Curved Linear
Array 4-9 MHz
2D
2DM-Mode
THI, 2D
THI, 2DM-Mode
PW Doppler
2DColor V
THIColor, 2D V
Tale 4MI/TI generating from applicable transducer/mode combinations
Track-3 follows the Output Display Standard for systems which include fetal Doppler applications The
acoustic output will not be evaluated on an application-specific basis, but the global maximum de-rated
I
spta
must be 2 mW/cm
2
and either the global maximum MI must be 19, or the global maximum de-
rated Isppa must be 19 W/cm
2
An exception is for ophthalmic use, in which case the TImax (TIS) is not
to exceed 1 I
spta3
 mW/CM
2
, and MI 23 Track-3 gives the operator the freedom to increase the
output acoustic power for a specific exam, and still limit output acoustic power within the global maximum
de-rated I
spta
 2 mW/cm
2
under an Output Display Standard
The system design allows full software control of the acoustic output, entry of new patient identification
data or change from a non-foetal to a foetal application, and the system may switch to an appropriate
default setting upon powering on These default setting levels are established before shipping and may be
reconfigured by the operator
For any ultrasound systems, Track-3 provides an Output Indices Display Standard The ultrasound system
and its
User Manual
contain the information regarding an ALARA (As Low As Reasonably Achievable)
education program from the clinical end-user and the acoustic output indices, MI and TI The MI describes
the likelihood of cavitation, and the TI offers the predicted maximum temperature rise in tissue as a result
of the diagnostic examination In general, a temperature increase of 2C must be present consistently
at one spot for 2 hours to cause possible fetal abnormalities Avoiding a local temperature rise above 1C
should ensure that no thermally induced biologic effect occurs When referring to the TI for potential
thermal effect, a TI equal to 1 does not mean the temperature will rise 1C It only means an increased
potential for thermal effects can be expected as the TI increases A high index does not mean that bioeffects
are occurring, but only that the potential exists and there is no consideration in the TI for the scan duration,
so minimizing the overall scan time will reduce the potential for effects These operator control and display
features move the safety responsibility from the manufacturer to the operator So it is very important to
have the ultrasound systems display the acoustic output indices correctly and the well-educated operator
to interpret the value appropriately
R
F
: De-rating factor
In Situ intensity and pressure cannot currently be measured Therefore, the acoustic power measurement is
normally done in the water tank, and when soft tissue replaces water along the ultrasound path, a decrease
in intensity is expected The fractional reduction in intensity caused by attenuation is denoted by the de-
rating factor (R
F
),
R
F
 1
(-1 afz)
Where a is the attenuation coefficient in dB cm
-1
MHz
-1
, f is the transducer center frequency, and z is the
distance along the beam axis between the source and the point of interest