How-To Guide

P34
Thermal Index (TI) Displays
T herearethreeT Isw hichused fordifferentcom binationsofsoft
tissueand boneintheareatobe examined.T heT Iisintendingtokeep usm aking
aw areofconditionthatcauseincreasedtem peratureelevations,nom atterat
surface,w ithinthetissue,oratthepointw heretheultrasoundisfocusingonbone.
T
h
erm al
index(T I)
S cannedM ode
U n
-
scannedM ode
S oftT i
ssue
T IS atS urface
T IS
S m allAperture
L argeAperture
BoneatFocus
(Cranialbone)
T IS atS urface
T IB
BoneatS urface
T IC
T IC
T heT Iinform stheuserabouttheconditionsthatexistthatm ightleadtoan
increase in tem peratureatthesurfaceofthebody,w ithinthebody tissue,oratthe
pointoffocusoftheultrasound beam on bone.T hatis,theT Iinform stheuserof
the potentialfortem peratureriseinbody tissue.Itisanestim ateoftem perature
increase in body tissue w ithspecificproperties.T heactualam ountofany
tem peratureriseisinfluencedby factorssuchastissue type,vascularity,m odeof
operation,and others.T heT Ishouldbeusedasaguide forim plem entingthe
AL AR A principle.T hebonetherm alindex (T IB)inform stheuseraboutpotential
heatingatornearthefocusafterthe ultrasound beam haspassedthroughsoft
tissueorfluid;forexam ple,atornearsecond-orthird-trim esterfetalbone.T he
cranialbonetherm alindex (T IC)inform stheuseraboutthepotentialheating of
boneatornearthesurface;forexam ple,cranialbone.T he softtissuetherm alindex
(T IS )inform sthe useraboutthepotentialforheatingw ithinsofthom ogeneous
tissue.You canchoosetodisplay T IS ,T IC,orT IB.Fordetailsonchangingthe T I
display,see
Controls Affecting the Indices
B m odeControls
• T ransducerFrequency
ColorControls
• ColorS ectorW idth:N arrow ercolorsectorw idthw illincreasecolorfram erate
andtheT Iw illincrease.T hesystem m ay autom atically decreasepulsevoltage
tostay below thesystem m axim um .A decreaseinpulsevoltagew illdecrease
theM I.
• ColorS ectorDepth:Deepercolorsectordepthm ay autom atically decrease
colorfram erateorselectanew colorfocalzoneorcolorpulse length.T heT I
w illchangeduetothecom binationoftheseeffects.Generally,the T Iw ill
decrease w ithincreasedcolorsectordepth.M Iw illcorrespond totheM Iof
the dom inantpulsetypew hichisacolorpulse.
O therControlEffects•
• B m odeDepth:Anincreasein2D depthw illautom atically decrease the2D
fram erate.T hisw illdecreasetheT I.T hesystem m ay alsoautom atically
choose adeeper2D focaldepth.A changeoffocaldepthm ay changetheM I.
T heM Idisplayed isthatofthezonew iththelargestM Ivalue.