Transducer review questions
What would cause a decrease in temporal resolution
An increase in line density
Most transducers usually have better
Axial resolution than lateral resolution
The range of frequencies present within the beam
Bandwidth
What type of interference results in a higher Amplitude sound wave
Constructive interference
What determines the divergence in the far field
Crystal diameter( aperture) And frequency
What electrical patterns produce electronic focusing in the ultrasound beam
Curved
What would improve temporal resolution( frame )
Decrease in the sector size, single transmit zone, and an increased pulse repetition frequency
Damping material produces
Decreased spatial pulse length, decreased sensitivity, wide bandwith, low quality factors
What would increase frame rate
Decreasing the imaging death which is the same as increasing the pulse repetition frequency
If the depth is increased what happens to frame rate
It decreases
What is true of the diameter of the sound beam in the Fresnel zone?
It decreases with distance from the Transducer
What happens to the diameter of the sound beam in the Fresnal zone
It decreases with distance from the transducer
What are synonyms for lateral resolution
LATA lateral, angular, transverse, azimuthal
What would most likely decreased beam Divergence in the far Field
Large Crystal diameter high frequency
What would most likely increase the near zone length-
Large crystal diameter and high frequency
What affects temporal resolution
Line density, image depth PRF and number of focal zones
Which resolution typically has the lowest number in clinical imaging
Longitudinal
What are synonym for Axial resolution
Longitudinal Axial radial range and depth(larrd)
Imaging Transducers typically have
Low Qfactors and wide bandwidths
What facilitates the transmission of sound from the element to the patient's skin
Matching layer
In an unfocused single element Transducer the width at the focal point of the sound beam measures how much compared to the beam width at the face of the Transducer
One half
Which transducer can be described as having the scan lines originate from a comment point of origin
Sector array
What part of the transducer stops ringing of the element
The damping material
What is considered the narrowest part of the sound beam
The focal zone
If the depth is increased and the frame rate is unchanged what must have decreased?
The number of lines per frame
Mechanical transducers
can be curved or linear in shape. They have a single circular disc-shaped active element. It uses a motor to steer the beam, most transducers are no longer mechanical, and may be focused with a lens or phased focused
Which type of resolution is an accurate representation of moving structures In real time
temporal resolution otherwise known as frame rate
Frame rate is determined by
the number of lines per frame/line density, number of focal zones, and the imaging depth(PRF)
Sector arrays are useful for imaging what areas?
those limited by ribs, gas filled-bowels, or lungs. The narrow near field and wide far field enable the transducer scan plane to be postitioned between or around these structures.
Large Crystal diameter and high frequency
what will decrease beam divergence in the far field
