Complete Solution
Inisoftitissue,iifitheifrequencyiofiaiwaveiisiincreaseditheiPro
pagationiSpeedi(PS)iwill...i-iCorrectiAnswer-
RemainitheiSameibecauseistiffnessiandidensityiaffectiProp
agationiSpeed.
Whatiisitheiaudibleirange?i-iCorrectiAnswer-20-20,000Hz
>20,000Hz=Ultrasound
Frequencyiisimeasurediini-iCorrectiAnswer-Hertzi(Hz)
isi
CyclesiperiSecond
Notiaffectedibyisonographeri
IncreaseiFrequency;iDecreaseiDepth
Aiperiodiisitheilengthiofitimeiititakesifori-iCorrectiAnswer-
oneicompleteiwavelengthitoipassiaifixedipoint
PRPiisideterminedibyi-iCorrectiAnswer-
Transmititimeiandireceiveitime.
Periodiisimeasurediini-iCorrectiAnswer-Timei(μs)
Whenitheisonographerichangesitheiimagingidepthiwhatipa
rametersiareichanged?i-iCorrectiAnswer-
PRP,iPRF,iDutyiFactor
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii Vendarsol
,Whatiisidutyifactor?i-iCorrectiAnswer-
Theipercentageiorifractioniofitimeithatitheisystemiisitransm
ittingiaipulsei(TimeiSoundiisiONioriON-Time).
PropagationiSpeediiniSOFTiTISSUEi-iCorrectiAnswer-
1.54imm/μs
(1540im/sec)
UnitiofimeasurementiforiPulseiDuration,iDutyiFactor,iPRP,i
andiPeriodi-iCorrectiAnswer-Time,i(μs)
Pulseidurationiisideterminedibyi-iCorrectiAnswer-
SoundiSourceiOnly
PulseiDurationiisicontrolledibyi-iCorrectiAnswer-
theiultrasoundisystemianditransducer
PulseiDurationiFormulai-iCorrectiAnswer-
pulseidurationi(μs)i=i#icyclesiinipulse/frequency(MHz)
PD=iNumberioficyclesiiniPulse/iFrequency(Hz)
SpatialiPulseiLengthi(SPL)i(measurement)i-
iCorrectiAnswer-
Theidistanceithatiaipulseioccupiesiinispaceifromitheistartitoi
theiendiofiaipulse.i
(mm)
Typicalivaluesiforispatialipulseilengthiinisoftitissue.i-
iCorrectiAnswer-0.1itoi1.0imm
Spatialipulseilengthiisideterminedibyi-iCorrectiAnswer-
soundisourceiandimedium
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii Vendarsol
, SpatialiPulseiLengthiisidirectlyiproportionalitoi-
iCorrectiAnswer-theiNumberiofiCyclesiinitheiPulse
andi
theiWavelength
(DirectlyiProportionalimeansithatiincreasediSPLiwilliincrea
seibothitheinumberioficyclesiinitheipulseianditheiwavelengt
hiifiincreased).
Spatialipulseilengthiisiinverselyiproportionalitoi-
iCorrectiAnswer-Frequencyi(MHz)
(InverselyiProportionalimeansithatiincreasediSPLiwillilowe
rifrequency.iThisiisibecauseiaxialiresolutioniisibetteriwithilo
werifrequency)
PulseiDurationi(PD)i-iCorrectiAnswer-
Theiactualitimeifromitheistartiofiaipulseitoitheiendiofithatipu
lse;iaisingleitransmit,italking,iori"on"itime.i
Timeitheipulseiisionitypicallyimeasurediini(ms).
PulseiLengthi-iCorrectiAnswer-
Theidistanceiofitheipulseistartitoiendiorithe
durationiorilengthiofiaisingleipulsei
PulseiLengthiisitypicallyimeasurediini(mm).
theiabilityiofianiobjectitoiresisticompressioniandirelatesitoit
heihardnessiofiaimedium?i-iCorrectiAnswer-Stiffness.i
Think:
↑iStiffnessi↑iSpeed
↓iDensityi↑iSpeed
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii Vendarsol