GE Logiq 3 Instruction Manual

Bioeffects
LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual 1-5
Direction 5122542-100 Rev. 2
Mechanical Bioeffect
In a similar manner ,the interact ion of ultrasound energy with 
tissue can produce a number of non-thermal or mechanical 
effects.The most significant is cavitation which results from the 
action of the oscillating ultrasou nd pressure on tiny gas bubbles 
with in the tissues. Cavitation has caused mechanical damage 
on a cellular level such as microscopic tears and hemorrhage in...

Acoustic Output
1-6LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual
Direction 5122542-100 Rev. 2
Operator Awareness and Actions to Minimize bioeffect 
The operator must be aware of the particular conditions that 
exist during the examination to recognize the potential for 
bioeffect and then take appropriate action to reduce the risk.The 
recognization of potential harm comes from an understanding of 
tissue characteristics and a re al-time knowledge of acoustic 
output.Taking appropriate...

Bioeffects
LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual 1-7
Direction 5122542-100 Rev. 2
Acoustic Output
awareness of the acoustic output level can be a difficult task for 
the operator,espcially when the objective is to obtaine a quality 
image.Older ultrasound equipment had limited means,if any,for 
indicating the acoustic output le vel.In most cases ,the operator 
had to be familiar with the output intensities as described in the 
operator manual.To improve op erator awareness of...

Acoustic Output
1-8LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual
Direction 5122542-100 Rev. 2
Acoustic Output(cont’d)
Tissue heating is more of a concern when the acoustic beam is 
stationary, so the thermal index is likely to increase when 
Doppler or M-Modes are selected.The influence of specific 
operator controls on acoustic ou tput is described along with the 
functional purpose of the control through out the user manual 
and a summary is provided in safety.
The operator now has easy...

Bioeffects
LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual 1-9
Direction 5122542-100 Rev. 2
Operator Intervention(Cont’d)
• Development and practice sk ills to localize anatomy and 
optimize image quality rapidly, then freeze the image as 
soon as the necessary diognostic information is 
obtained.It takes time for tissue temparatures to 
increase ,so reducing exposue r time can significantly 
reduce the potential for injury.
• Avoid susceptible tissues  , if possible ,by changing 
probe...

Acoustic Output
1-10LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual
Direction 5122542-100 Rev. 2
Implementing the ALARA Methods
The Primary objective for any ultrasound examination is to 
obtaine diagnostic information of  sufficient quality to benefit the 
patient. Image Quality can usually be improved by increasing 
the acoustic output or taking  more time to refine the 
image.These same actions, however, will also  increase the risk 
of harmful bioeffects when imaging sensitive tissues or...

Bioeffects
LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual 1-11
Direction 5122542-100 Rev. 2
Clinical Instruction for Fetal Use
Following are illustrative examples  of clinical instructions for 
fetal Doppler use which were prepared by Harold 
Schulman,M.D. and Jhon Hobbins,M.D.
Umbilical artery
To Obtain a signal:
For continuous wave doppler instrument , Place the pencil probe 
with appropriate conducting gel on the meternal abdomen. The 
volume should be at a comportable level and the...

Acoustic Output
1-12LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual
Direction 5122542-100 Rev. 2
Uterine artery 
For Continuous wave doppler systems,place the pencil probe in 
the lower lateral portion of the mother’s abdomen.generally just 
above the groin and directed toward the cervix.Adjust the angle 
or position until the characterist ic wave form of the uterine/ 
arcuate artery is obtained.Without visualization, it is important to 
search carefully for the wave form with the greatest...

Bioeffects
LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual 1-13
Direction 5122542-100 Rev. 2
Efficacy Of Fetal Doppler
The following are clinical  obstritrical where ther are experimental 
data that demonstrate the effica cy of Doppler.Provided by Jhon 
C.Hobbins,M.D. and Peter Burns,Ph.D.4
IUGR
Many studies have shown a good correlation between abnorma 
waveform( or decreased blood flow) and increased perinatal 
mortality5, Fetal hypoxia 6,7,8 ,and neonatal eveents such as 
necrotizing...

Acoustic Output
1-14LOGIQ 3 Expert/LOGIQ 3 Pro/LOGIQ 3 Advanced Reference Manual
Direction 5122542-100 Rev. 2
Efficacy Of Fetal Doppler(cont’d)
Summary
It is important to realize that current investigation DOES NOT 
support the concept that Doppler waveform analysis in the 
above obestritrical conditions prov ides information that is meant 
to replace other conventional tests, or the biophysical profile, 
also, it should not replace classical non-doppler ultrasound 
scanning methods. Rather , it a ppears...