8/10/2019 UT Terms and Definitions

1/3

Damping

Damping is a process, material, design, and mounting technique used to

reduce the pulse duration or ringingof the transducer. Special material isapplied to the back of the transducer in order to reduce the amplitudeandpulse lengthof the sound wave.Damping improves axial resolution by reducing pulse length. Thereby thelateral resolution increases

Dead Zone

The dead or ring down zone is the distance from the front face of thetransducerto the first echo that is identifiable. The signals from this

region are unsuitable. The dead zone is the result of transducerringingand reverberations from the interface between the transducer and thescanned obect. !mpedance matching between the transducerand thereceiveris important to avoid electrical ringing."ith an increase of the frequency, the pulse lengthand the depth of thedead zonedecrease, if all other parameters remain constant. Theacoustic power also affects the depth of the dead zone.

Acoustic Mismatch

#coustic mismatch arise at the boundary between two different mediawhere reflection and refractionoccurs.

Axial resolution

#xial resolution is the minimum separation between two interfaces locatedin a direction parallel to the beam $obects above and below each other%so that they can be imaged as two different interfaces. The axial spaceresolutiondirectly relates with the wave frequency, but higher frequencies

have lower penetrationinto tissues.The axial resolutionis inversely proportional to the frequencyof thetransducerdepending on the size of the patient. The higher the frequencythe lower the axial resolutionin large patients. This state results from therapid absorptionof the ultrasound energy with lower penetration. &owerfrequencies are utilized to increase depth of penetration.

http://www.us-tip.com/serv1.php?type=db1&dbs=Ringinghttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplitudehttp://www.us-tip.com/serv1.php?type=db1&dbs=Soundhttp://www.us-tip.com/serv1.php?type=db1&dbs=Axial%20Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Lateral%20Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Zonehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Echohttp://www.us-tip.com/serv1.php?type=db1&dbs=Zonehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Ringinghttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Impedancehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Receiverhttp://www.us-tip.com/serv1.php?type=db1&dbs=Ringinghttp://www.us-tip.com/serv1.php?type=db1&dbs=Ringinghttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Depthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Zonehttp://www.us-tip.com/serv1.php?type=db1&dbs=Powerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Depthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Zonehttp://www.us-tip.com/serv1.php?type=db1&dbs=Reflectionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Refractionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Penetrationhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Absorptionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Penetrationhttp://www.us-tip.com/serv1.php?type=db1&dbs=Depthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Penetrationhttp://www.us-tip.com/serv1.php?type=db1&dbs=Ringinghttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplitudehttp://www.us-tip.com/serv1.php?type=db1&dbs=Soundhttp://www.us-tip.com/serv1.php?type=db1&dbs=Axial%20Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Lateral%20Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Zonehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Echohttp://www.us-tip.com/serv1.php?type=db1&dbs=Zonehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Ringinghttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Impedancehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Receiverhttp://www.us-tip.com/serv1.php?type=db1&dbs=Ringinghttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Depthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Zonehttp://www.us-tip.com/serv1.php?type=db1&dbs=Powerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Depthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Zonehttp://www.us-tip.com/serv1.php?type=db1&dbs=Reflectionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Refractionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Penetrationhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Absorptionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Penetrationhttp://www.us-tip.com/serv1.php?type=db1&dbs=Depthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Penetration

8/10/2019 UT Terms and Definitions

2/3

Bandwidth

The ultrasound bandwidthdescribes the number or range of frequencies.

The reflected Dopplerbandwidthincrease when the Dopplerbeamstrikes red blood cells traveling at many different speeds $as in turbulentflow%.

Narrow Bandwidth

# narrow or tuned 'andwidth describes a small frequencyspectrum ofpulses. "ith the (ourier transformation method a pulse or amplifiercanbe subscribed with its bandwidth. !t is usually expressed with a )d' dropof maximum amplitude, subscribing the bandwidth between the edges of

the curve.The selection of bandwidth is essential for achieving certain test results*narrow bandwidth for highly sensitive scans or broad banded for highresolutionscans. The fast (ourier transformationuses beside the echoamplitudeevaluation method the capability of the echofrequency+bandwidth information.

Q-value

The degree that a transducer is finely tuned to specific narrow frequencyrange.(or example # low -value means wide bandwidthand high -value means narrow bandwidth.

Pulse repetition freuenc!

$/0(% The pulse repetition frequency is the number of pulses per second.The usual range for echocardiographs is between 122 and 3222 pulsesper second. The /0( varies with the type of modein operation.

http://www.us-tip.com/serv1.php?type=db1&dbs=Rangehttp://www.us-tip.com/serv1.php?type=db1&dbs=Doppler%20Ultrasoundhttp://www.us-tip.com/serv1.php?type=db1&dbs=Doppler%20Ultrasoundhttp://www.us-tip.com/serv1.php?type=db1&dbs=Flowhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplifierhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplitudehttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Fast%20Fourier%20Transformationhttp://www.us-tip.com/serv1.php?type=db1&dbs=Echohttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplitudehttp://www.us-tip.com/serv1.php?type=db1&dbs=Echohttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Rangehttp://www.us-tip.com/serv1.php?type=db1&dbs=Rangehttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Rangehttp://www.us-tip.com/serv1.php?type=db1&dbs=Modehttp://www.us-tip.com/serv1.php?type=db1&dbs=Rangehttp://www.us-tip.com/serv1.php?type=db1&dbs=Doppler%20Ultrasoundhttp://www.us-tip.com/serv1.php?type=db1&dbs=Doppler%20Ultrasoundhttp://www.us-tip.com/serv1.php?type=db1&dbs=Flowhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplifierhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplitudehttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Resolutionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Fast%20Fourier%20Transformationhttp://www.us-tip.com/serv1.php?type=db1&dbs=Echohttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplitudehttp://www.us-tip.com/serv1.php?type=db1&dbs=Echohttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Rangehttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Bandwidthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Rangehttp://www.us-tip.com/serv1.php?type=db1&dbs=Mode

8/10/2019 UT Terms and Definitions

3/3

/oint reflector 4 Spherical wavefront

# point scatterer is a reflectorwith a diameter much smaller than theultrasound wavelength. The reflectionfrom blood is a typical example of

point scattering. 0ed blood cells are with 56m versus 2.77 mmwavelengthat 8.3 9:z, smaller than any ;S wavelength. The individualcells are not only the point scatterers, ultrasound is scattered wheneverthere is a change in acoustic impedance, and in blood such changes arecaused by variable cell concentration. These local fluctuations in cellconcentration have a spatial extent that is also much smaller than theultrasound wavelength, and they therefore act as point scatterers.# point scatterer gives rise to sphericalwavelets spreading out in alldirections with the scatterer itself at the center of the sphere. Thesphericalwavelets from one single point scatterer are much too weak tobe detected by the transducer, but constructive interference between

numerous wavelets will produce backscatteringof higher amplitudeechoes with parallel wavefronts, also in the direction of the ultrasoundtransducer.

Huygens princople

:uygens principle states that an expanding sphere of waves behaves asif each point on the wavefrontwere a new source of radiation of thesame frequency and phase. The principle explains how a flat ultrasoundtransducercan transmit a narrow ultrasound beam, which in the near fieldis confined to the dimensions of the transducer surface."phericalwavelets are emitted from numerous point sources on thetransducersurface. They interfere to form a narrow, slightly convergingbeam of ultrasound in the near field. The wavefronts in the beam arenearly parallel. # precondition for this interferenceis that the transducersurface is much larger than the ultrasound wavelength.

http://www.us-tip.com/serv1.php?type=db1&dbs=Reflectorhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Reflectionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Acoustic%20Impedancehttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Interferencehttp://www.us-tip.com/serv1.php?type=db1&dbs=Backscatteringhttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplitudehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Near%20Fieldhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Near%20Fieldhttp://www.us-tip.com/serv1.php?type=db1&dbs=Interferencehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Reflectorhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Reflectionhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Acoustic%20Impedancehttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelengthhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Interferencehttp://www.us-tip.com/serv1.php?type=db1&dbs=Backscatteringhttp://www.us-tip.com/serv1.php?type=db1&dbs=Amplitudehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Frequencyhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Near%20Fieldhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Near%20Fieldhttp://www.us-tip.com/serv1.php?type=db1&dbs=Interferencehttp://www.us-tip.com/serv1.php?type=db1&dbs=Transducerhttp://www.us-tip.com/serv1.php?type=db1&dbs=Wavelength