Physics and Instrumentation Ch 2
Which of the following electrical patterns produces electronic focusing of the ultrasound beam A Curved B Sloped C Spiral D Circular
A A curved firing pattern of the piezoelectric elements indicates focusing of the beam
To produce a transducer with a higher frequency one should A Use a thinner piezoelectric element B Use a thicker piezoelectric element C Use more damping D use less damping
A A thinner piezoelectric element will yield a higher frequency
Which of the following would cause a decrease in temporal resolution? A Increased line density B Decreased sector size C Single transmit zone D Increased PRF
A An increase in line density would decrease temporal resolution
Which of the following is not a synonym for axial resolution A Angular B Range Depth Radial
A Angular is a synonym for lateral resolution
Which of the following is not a method of creating 3D images A Broadband technology B 2D array technology C Freehand technique D Mechanical technique
A Broadband technology allows a variety of frequencies to be used as part of imaging but not to create 3D images
Which of the following transducers is not used for imaging A Continuous wave transducers B Curved sequenced array transducers C Linear sequenced array transducers D Phased array transducers
A CW transducers do not produce an image
Which transducer has no range resolution A Continuous wave transducers B Curved sequenced array transducers C Linear sequenced array transducers D Phased array transducers
A CW transducers do not time how long it takes pulses to travel so they have no range resolution (no image)
Which type of interference results in a higher amplitude sound wave? A Constructive interference B Destructive interference C True interference D False interference
A Constructive interference (in phase waves meet and the amplitudes are added to form one large wave)
Which of the following best describes the components of the damping material A Epoxy resin loaded with tungsten B Resin made with lead zirconate titanate C Polyvinylidene fluoride D Tungsten impregnated with lead
A Epoxy resin loaded with tungsten
Which of the following is true concerning the frequency and the near zone length, assuming a single element unfocused transducer A The higher the frequency, the longer the near zone length B The lower the frequency, the longer the near zone length C Frequency and near zone length are not related D Increasing the frequency causes divergence in the near field
A In a single element unfocused transducer the higher the frequency the longer the near zone length
Imaging transducers typically have A Low quality factors, wide bandwidths B High quality factors, narrow bandwidths C Low quality factors, narrow bandwidths D High quality factors, wide bandwidths
A Low quality (low purity of the beam) and wide bandwidth due to damping
Which resolution typically has the lowest number in clinical imaging? A Longitudinal B Lateral C Transverse D Azimuthal
A Most transducers typically have better axial (LARD) resolution than lateral (LATA)
Which of the following is defined as the minimum distance two reflectors can be, a parallel to the beam, and still appear on the screen as two dots A Range resolution B Angular resolution C Contrast resolution D Transverse resoultion
A Range resolution (axial resolution)
Which of the following transducers can be described as having the scan lines originate from a common point of origin A Sector array B Vector array C Curvilinear array D Linear sequenced array
A Sector array comes to a point at the top because all of the scan lines come from a comment point of origin
Which of the following is not a component of spatial resolution A Frame resolution B Contrast resolution C Axial resolution D Elevational resolution
A Spatial resolution consists of axial, lateral, Elevational and contrast resolution
Which of the following is represented as time, or the ability to display structures in real time A Temporal resolution B Axial resolution C Longitudinal resolution D Contrast resolution
A The higher the temporal resolution or frame rate, the better the ability to represent structures in real time
Which of the following is not a true statement A Lateral resolution varies with depth B A larger aperture results in a shorter near zone length C A larger aperture produces less divergence in the far field D Lateral resolution may also be referred to as azimuthal resolution
B A larger aperture results in a longer near zone length
Which of the following describes the range of frequencies present within the beam? A Matching layer B Bandwidth C Array D Wavefront
B Bandwidth is the range of frequencies within the sound beam
Damping material produces all of the following except: A Decreased sensitivity B Increase SPL C Wide bandwidths D Low quality factors
B Damping material decreases the spatial pulse length by decreasing the number of cycles in a pulse
Which of the following is the resolution in the third dimension of the beam A Lateral resolution B Elevational resolution C Contrast resolution D Longitudinal resolution
B Elevational resolution refers to the resolution in the third dimension of the beam, the slice thickness plane
along with crystal diameter, the divergence in the far field is also determined by which of the following? A Spatial pulse length B Frequency C Propagation speed D Line density
B Frequency
Temporal resolution relates to which of the following A Lateral resolution B Frame rate C Range ambiguity D Element diameter
B Temporal resolution is another term for frame rate
Which of the following is true of the diameter of the sound beam in the Fresnel zone A It increases with distance from the transducer B It decreases with distance from the transducer C It does not change with distance from the transducer D It is unpredictable
B The Fresnel zone is the near zone so it decreases as it nears the focal zone
Which of the following best describes the frame rate A The frame rate is equal to the pulse repetition frequency multiplied by the lines per frame B The frame rate is equal to the pulse repetition frequency divided by the lines per frame C The frame rate is equal to the pulse repetition period divided by the lines per frame D The frame rate is equal to the pulse repetition period multiplied by the lines per frame
B The frame rate is equal to the pulse repetition frequency divided by the lines per frame
Which of the following facilitates the transmission of sound from the element into the patient's skin A Damping material B Matching layer C Tungsten covering D Focusing material
B The matching layer is used to minimize the impedance mismatch between that of the element and that of the patient's skin
The portion of the transducer that comes in contact with the patient is the A backing material B Matching layer C Wire D Damping material
B The matching layer or face of the transducer
If the depth is increased and the frame rate is unchanged, what else must have decreased A The pulse repetition period B The number of lines per frame C The duty factor D The output factor
B The number of lines per frame (normally if depth is increased the frame rate would decrease)
Which of the following produces a pie shaped image A Linear sequenced array B Phased array C Curved sequenced array D Convex transducer
B The phased array produces a pie shaped or sector image (some create a vector shape image which is like a sector but with a flat top)
Which of the following transducers is also referred to as a sector or vector transducer A Linear sequential array B phased array C Continuous wave transducer D Curved sequential array transducer
B The phased array transducer
How are ultrasound transducers typically sterilized A Heating to the curie temperature B Cold sterilization methods C Autoclaving D Alcohol immersion
B Typically disinfected using a cold high level disinfectant solution although they may be sterilized using a warmed hydrogen peroxide solution in a tabletop device
Which of the following would most likely increase the near zone length A Large crystal diameter, low frequency B Small crystal diameter, low frequency C Large crystal diameter, high frequency D Small crystal diameter, high frequency
C A large crystal diameter (aperature) and high frequency would increase the near zone length the most compared to the other options
Which of the following is not true of damping A Damping decreases the number of cycles in a pulse B Damping decreases spatial pulse length C Damping worsens axial resolution D Damping decreases the sensitivity of the transducer
C Damping improves axial resolution by shortening the pulse (by decreasing the number of cycles in a pulse)
Which of the following describes the result of destructive interference A The resulting wave is much larger than the original wave B The resulting wave is a little larger than the original wave C The resulting wave is smaller than the original wave D Destructive interference does not occur with diagnostic imaging
C Destructive interference occurs when out of phase waves meet and the amplitude of the resulting wave is small than either of the original waves
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 A One fourth B One third C One half D Equal
C In an unfocused, single element transducer, the focal point measures one half of the beam width at the face of the transducer
Which of the following would most likely decrease the beam divergence in the far field A Large crystal diameter, low frequency B Small crystal diameter, low frequency C Large crystal diameter, high frequency D Small crystal diameter, high frequency
C Large crystal diameter (aperture) and high frequency would decrease the beam divergence in the far field
Along with image depth, which of the following also determines the frame rate A Axial resolution B Damping C Number of lines per frame D Lateral resolution
C Lines per frame
Which of the following would be best utilized for imaging of deep structures in the abdomen A Endocavity transducer B Linear sequenced array transducer C Curved sequenced array transducer D Continuous wave transducer
C Of the choices listed the curved sequence array would be best. Endocavity are high frequency and linear transducer have limited depth and near field of view
Which of the following is defined as changing the timing of the shocking of the elements in order to shape and steer the beam A Angulation B Focusing C Phasing D Bundling
C Phasing is a method of focusing and/or steering the beam by applying electrical impulses to the piezoelectric elements with small time difference between shocks
Which of the following will not affect temporal resolution A Line density B Image depth C Spatial pulse length D Number of focal zones
C Spatial pulse length has no effect on temporal resolution
Which of the following shortens the length of the pulse by decreasing the number of cycles in the pulse A Matching material B Piezoelectric element C Backing material D PZT
C The backing material is also called damping material
Which of the following may also be referred to as the far zone A Frame zone B Fresnel zone C Fraunhofer zone D Frankincense zone
C The far zone may also be referred to as the Fraunhofer zone
Which of the following is the part of the transducer that stops the ringing of the element A Matching layer B Housing C Damping material D Insulator
C. the damping material/backing material
Which of the following is not a characteristic of an unfocused single element transducer A At the face of the transducer, the beam diameter is equal to the element diameter B At a distance of one near zone length, the beam diameter is equal to one half of the diameter of the element C At a distance of two near zone lengths, the beam diameter again equals the element diameter D At the face of the transducer, the beam diameter is twice the size of the element thickness
D Assuming an unfocused, single element transducer, at the face of the transducer, the beam diameter is equal to the element diameter
What does heat sterilization do to an ultrasound transducer A Gives it better axial resolution B Improves the lateral resolution of the transducer C Kills all the bacteria and viruses D Kills pathogens and destroys the transducer
D Destroys the transducer because piezoelectric elements cannot ever reach the Curie point again
Which of the following could be considered the narrowest part of a sound beam A Far zone B Near zone C Fresnel zone D Focal zone
D Focal zone
What states that waves are the result of the interference of many wavelets produced at the face of the transducer A Curie's principle B Snell's law C Bernoulli's law D Huygen's principle
D Huygen's principle states that waves are the result of the interference of many wavelets produced at the face of the transducer
Which of the following would cause an increase in frame rate A Multifocusing B Increased line density C Increased imaging depth D Increased PRF
D Increased PRF (which is the same as decreasing imaging depth) would increase the frame rate
Which type of resolution is an accurate representation of moving structures A Lateral resolution B Azimuthal resolution C Spatial resolution D Temporal resolution
D Temporal resolution (frame rate) is the ability to display moving structures in real time
Which of the following is not a true statement about a mechanical transducer A It uses a motor to steer the beam B Most transducers are no longer mechanical C May be focused with a lens or phased focused D There are no moving parts
D The mechanical transducer does have moving parts.
Which of the following is not true of the linear sequenced array transducer A Rectangular shape image B Firing is sequential C Electronically focused D the elements are arranged in a ring
D They are not arranged in a ring
