Questions and Answers
Which type of transducer will allow the Sonographer to adjust slice thickness to reduce the display of image artifacts?
Which of the following transducers uses a beam former?
Which of the following can be used for backing material in a PW transducer?
A high frequency transducer has less depth penetration than a lower frequency transducer.
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An annular array can electronically focus the beam.
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Which of the following correctly describes a dedicated continuous wave Doppler transducer?
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__________ is defined as the range of frequencies contained in the US pulse.
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As the element diameter decreases, the focal length _____________.
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What type of resolution is degraded in 2-D transducer arrays?
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Which of the following describes the primary advantages of a 1.5D array over a 1D array?
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What is the bandwidth of a 7 MHz transducer that emits a range of frequencies between 4 MHz and 10 MHz?
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The operating frequency of the transducer is also called the:
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A curved array transducer is preferred over a sector array transducer of the same frequency for fetal and abdominal imaging because:
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Mirrors and lenses can be used to __________________.
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As the transducer frequency increases, the quality factor ______________________.
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Which of the following correctly describes how a linear array transducer produces a trapezoid field of view?
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What beam formation technique is used to produce the sector field of view in a phased array transducer?
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If you change from a transducer with a 40 mm crystal thickness to one with a 20 mm crystal thickness, how will the frequency of the sound produced change?
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Which of the following factors affect the focal length of the transducer?
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Which statement regarding high frequency transducers is correct?
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What transducer component reduces the 'ringing' of the crystal, improves axial resolution, and reduces SPL?
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The frequency of the transducer depends primarily on the ________________.
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What type of transducer has approximately 200 elements arranged side by side and produces only a rectangular shaped field of view?
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If the fundamental frequency of a transducer is 3 MHz, what is the second harmonic frequency for this transducer?
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What matching layer for a transducer is usually made of plastic?
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The wider the element diameter, the ____________.
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To obtain a longer near zone, ______ from a 3 MHz to a 6 MHz transducer.
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What type of probe is preferred for cardiac imaging?
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What type of probe is preferred for extremity vascular imaging?
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The wider the element diameter, the ____________.
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The crystal in the ultrasound transducer converts:
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An US system/transducer that performs Acoustic Radiation Forced impulse (ARFI) is used to assess:
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What is the name of the transducer component labeled letter G?
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A backing layer similar to the silicon substrate in a capacitive micro-machined US transducer is necessary to counteract excessive:
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An 8 MHz transducer would have elements that are _____________ than a 4 MHz transducer.
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Which of the following is an advantage of a 2-D linear phased array over a 1-D linear phased array transducer?
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What is an advantage of the new Capacitive Micromachined Ultrasonic Transducers (CMUT) compared to traditional transducer arrays?
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Which of the following describes a vector array transducer?
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Capacitive Micromachined Ultrasonic Transducers (CMUT):
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What type of transducer produced the image?
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Which type of transducer would be used to evaluate a palpable lump in the neck?
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Annular arrays must be mechanically steered, linear arrays use electronic steering.
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As the propagation speed of the crystal increases, what happens to the frequency of the transducer?
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The main advantage of a curvilinear transducer over a vector transducer is:
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What determines the frequency of a capacitive micromachined US transducer?
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Which of the following is correct regarding endocavity probes?
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Which of the following is an advantage of a 2-D linear phased array over a 1-D linear phased array transducer?
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The linear transducer you are using has 7-5 MHz printed on the side of the housing. What probe characteristic is this?
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Why is a 2D array preferred over a 1D array for superficial imaging?
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During an exam, you change from a 5 MHz transducer to a 3 MHz transducer. How does the wavelength change?
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Which of the following transducers will produce the lowest frequency sound waves?
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The pulser sends the voltage spike to the ___________________.
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Which of the following transducer components reduces the sensitivity and efficiency of the US system?
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Which of the following transducers provides the best spatial resolution of the cardiac structures?
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CW probes do not require any backing material.
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The choice of frequency for an exam is dependent on the ___________________ needed for an optimal exam.
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What phenomenon is described as the conversion of a pressure wave into an electrical voltage?
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The acoustic impedance of the matching layer is usually very low.
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Which of the following transducer frequencies can be used for imaging or therapeutic purposes?
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What type of transducer array has the fewest number of elements?
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Which of the following correctly describes how the elements of a sequential linear transducer are excited?
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Which of the following describes a multi-dimensional array?
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Which of the following exams would benefit from an exam performed with a multidimensional array?
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Which transducer would provide the lowest attenuation rate?
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Increasing the transducer frequency on a multihertz transducer will: ____________.
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Which of the following transducers would be most useful for imaging deeper structures?
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Materials used for the matching layer of a transducer must have an impedance between impedance levels of the ____________________.
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What type of transducer produced the image?
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The damping material causes a _______________ bandwidth and a ____________________ quality factor.
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Which transducer should be used for evaluation of an area within 1 cm of the transducer face?
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What determines the transducer frequency used for the evaluation of a foreign body?
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Which type of transducer has the smallest field of view in the near field?
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The vector array has a smaller footprint than the phased sector array.
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The matching layer is usually made of ____________.
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What is the name of the transducer component that is not necessary in the construction of a capacitive micromachined US transducer?
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Transducers can be electronically focused by: ____________.
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What system parameter is decreased with a high frequency transducer?
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Which of the following occurs with the implementation of backing material in a transducer?
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What type of transducer has a cylindrical beam profile?
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Diagnostic US is described as frequencies greater than:
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What is the name of the transducer component labeled letter C?
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Linear phased arrays utilize what type of focusing?
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Which of the following transducers will produce the highest frequency sound waves?
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What is the name of the transducer component labeled letter F?
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Which transducer component improves elevational resolution?
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What shape is the image display from a sequential linear transducer?
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What type of transducer produced the image?
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Which of the following transducers would be preferred for breast imaging?
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During an US exam of the liver, you change from a 5 MHz transducer to a 3 MHz transducer. How does the propagation speed through the liver change?
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A __________ MHz transducer will have the thinnest element.
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Transducers can be electronically focused by:
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Which of the following is necessary for a Multihertz transducer?
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Study Notes
Ultrasound Transducer Types and Functions
- 2-D phased curvilinear array allows adjustment of slice thickness to minimize image artifacts.
- Sector phased array transducers utilize a beam former for creating images.
- Annular arrays have the capability to electronically focus the beam for improved resolution.
Transducer Materials and Components
- Epoxy is commonly used as backing material in pulsed wave (PW) transducers.
- Damping material reduces the ringing of the crystal, thus improving axial resolution and decreasing spatial pulse length (SPL).
- The matching layer is typically made of plastic to optimize acoustic impedance.
Frequency and Resolution Characteristics
- High frequency transducers, such as 8 MHz, have less depth penetration compared to lower frequency counterparts, affecting diagnostic capabilities.
- Bandwidth refers to the range of frequencies contained in the ultrasound pulse. A transducer with a 7 MHz fundamental frequency has a bandwidth of 6 MHz.
- Temporal resolution is degraded in 2-D transducer arrays, impacting the ability to capture fast-moving structures.
Focal Length and Element Size
- As element diameter decreases, the focal length also decreases, influencing beam characteristics.
- The focal length of a transducer is affected by both element diameter and frequency.
- A 1.5D array provides variable elevation focus, enhancing imaging compared to a 1D array with a fixed elevation focus.
Transducer Performance and Imaging Techniques
- Elements in a sequential linear transducer are excited in a specific, unchanging order for image formation.
- Capacitive Micromachined Ultrasonic Transducers (CMUT) utilize miniature elements with fixed components and flexible membranes for high-resolution imaging.
- The curved array transducer is preferred over sector arrays for specific applications like fetal and abdominal imaging due to its wider near field.
Quality Factor and Bandwidth
- The quality factor increases as the transducer frequency increases, which can affect image clarity and detail.
- Damping materials contribute to a wider bandwidth but lower quality factor, potentially impacting overall system sensitivity.
Specialized Imaging and Functionality
- Multi-Hz transducers operate at multiple frequencies, offering broad bandwidth for versatile imaging applications.
- Various transducer configurations, such as curved phased arrays or vector phased arrays, are tailored for specific clinical applications, including cardiac or extremity vascular imaging.
- An annular array transducer features a cylindrical beam profile, suitable for specific imaging needs.
General Principles of Ultrasound
- The Piezoelectric effect describes the conversion of mechanical energy to electrical energy within transducers.
- Propagation speed and crystal characteristics significantly impact the frequency and resolution of the ultrasound produced.
- At lower frequencies, such as 2.5 MHz, ultrasound exhibits lower attenuation rates, affecting the depth of imaging.
Examination Practices
- Frequency choice during ultrasound exams is crucial for ensuring optimal penetration and resolution based on the structure being examined.
- A 12 MHz linear phased array would be suitable for detailed evaluations, such as breast imaging due to its fine resolution capabilities.
- Understanding the differences in transducer design and function is imperative for selecting the proper type for each diagnostic procedure.
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Description
This quiz explores the different types of ultrasound transducers and their specific functions, focusing on array configurations and material components. Understand how frequency impacts resolution and diagnostic capabilities, along with the materials used in transducer construction.