Print Chapter 3 Transducers - Review flashcards - Easy Notecards

Print Options

← Back to notecard set|Easy Notecards home page

Instructions for Side by Side Printing

Print the notecards
Fold each page in half along the solid vertical line
Cut out the notecards by cutting along each horizontal dotted line
Optional: Glue, tape or staple the ends of each notecard together

To print: Ctrl+PPrint as a list

100 notecards = 25 pages (4 cards per page)

Chapter 3 Transducers - Review

front 1 A transducer converts one form of ______________ to another.	back 1 Energy
front 2 Ultrasound transducers convert ________________ energy into ____________ energy, and vise versa	back 2 Electric, ultrasounf
front 3 Ultrasound transducers operate on the ______________ principle.	back 3 Piezoelectric
front 4 Single-element transducers are in the form of ____________.	back 4 Disks

front 5 The ___________ of a transducer element changes when voltage is applied to its faces.	back 5 Thickness
front 6 The term transducer is used to refer to a transducer __________ or to a transducer ______________.	back 6 Element, assembly
front 7 A transducer _________________ is part of a transducer _________________.	back 7 Element, assembly
front 8 An electrical voltage pulse, when applied to a transducer, produces an ultrasound _____________ of a _____________ that is equal to that of the voltage pulse.	back 8 Pulse, frequency

front 9 The resonance frequency of an element is determined by by its ______________.	back 9 Thickness
front 10 Operating frequency ______________ as transducer element thickness is increased.	back 10 Decreases
front 11 The addition of damping material reduces the number of ___________ in the pulse, thus improving ___________ __________. It increases ______________.	back 11 Cycles, axial resolution, bandwidth
front 12 Damping material reduces the _____________ of the transducer and _______________ _______________. It increases _______________.	back 12 Efficiency, sensitivity

front 13 Ultrasound transducers typically generate pulses of ___________ or _____________ cycles.	back 13 Two, three
front 14 For a particular transducer element material, if a thickness of .4 mm yields an operating frequency of 5 MHz, the thickness required for an operating frequency of 10 MHz is ________________ mm.	back 14 .2 mm .4 mm / 2= .2 mm
front 15 Which of the following transducer frequencies would have the thinnest element? A) 2 MHz B) 3 MHz C) 5 MHz D) 7 MHz E) 10 MHz	back 15 E) 10 MHz
front 16 The matching layer on the transducer surface reduces _________ caused by _____________.	back 16 reflection

front 17 A coupling agent on the skin surface eliminates reflection caused by _______________.	back 17 air
front 18 True or False? Damping lengthens the pulse.	back 18 False
front 19 True or False? Damping increases efficiency.	back 19 False
front 20 The damping layer is in front or back of the element.	back 20 Back

front 21 The matching layer is in front or back of the element.	back 21 Front
front 22 The matching layer has ___________ impedance	back 22 intermediate
front 23 Elements in linear arrays are in the form of _____________.	back 23 rectangles
front 24 Transducer assemblies are also called ___________. A) transducers B) probes C) scanheads D) scan converters E) skinheads F) more than one of the above	back 24 F) more than one of the above A) transducers B) probes C) scanheads

front 25 Operating frequency is also called ________.	back 25 resonance frequency
front 26 Mixtures of a piezoelectric ceramic and a non-piezoelectric polymer are called _______________.	back 26 composites
front 27 To operate a transducer at more than one frequency requires ______________ _____________.	back 27 broad bandwidth
front 28 It is practical to attempt to operate a 5-MHz transducer with a bandwidth of 1 MHz at 6 MHz?	back 28 No these frequencies are outside the bandwidth (4.5 to 5.5 MHz)

front 29 It is practical to attempt to operate a 5-MHz transducer with a bandwidth of 2.5 at 3 and 7 MHz?	back 29 No these frequencies are outside the 2.5-MHz bandwidth (3.75 to 6.25 MHz)
front 30 A beam is divided into two regions, called the _______ zone and the ____________ zone.	back 30 Near, far
front 31 The dividing point between the two regions is at a distance from the transducer equal to ___________ _______ length.	back 31 Near zone
front 32 Transducer size is also called _______________.	back 32 aperture

front 33 Near zone length increases with increasing source __________ and ______________.	back 33 aperture, frequency
front 34 Which transducer element has the longest near zone? A) 6 mm, 5 MHz B) 6 mm, 7 MHz C) 8 mm, 7 MHz	back 34 C) 8 mm, 7 MHz
front 35 A higher frequency transducer produces a ____________ near-zone length.	back 35 longer
front 36 A smaller frequency transducer produces a ____________ near-zone length.	back 36 shorter

front 37 True or False? A transducer with the near-zone length of 10 cm can be focused at 12 cm.	back 37 false can focus only in the near zone
front 38 Which of the following transducers can focus at 6 cm? A) 5 MHz, near-zone length of 5 cm B) 4 MHz, near-zone length of 6 cm C) 4 MHz, near-zone length of 10 cm D) B and C E) none of the above	back 38 C) 4 MHz, near-zone length of 10 cm
front 39 Sound may be focused by using a ____________. A) curved element B) lens C) phased array D) more than one of the above.	back 39 D) more than one of the above. A) curved element B) lens C) phased array
front 40 True or False? Focusing reduces the beam diameter at all distances from the transducer	back 40 False

front 41 The distance from a transducer to the location of the narrowest beam width produced by a focused transducer is called ______________.	back 41 focal length
front 42 Transducer arrays are transducer assemblies with several transducer _______________.	back 42 elements
front 43 Linear arrays scan beams by _____________ element groups.	back 43 sequencing
front 44 A phased linear array with a single line of elements can focus in ________________ dimensions.	back 44 One the lateral dimensions

front 45 Focusing in section thickness can be accomplished with _________ elements of a _______.	back 45 curved, lens
front 46 Electronic focusing in section thickness requires multiple rows of ___________.	back 46 elements
front 47 Match the following A) Linear array B) Phased array C) Convex array 1) Voltage pulses are applied in succession to groups of elements across the face of a transducer 2) Voltage pulses are applied to most or all elements as a group, but with small time differences	back 47 A) Linear array - 1) Voltage pulses are applied in succession to groups of elements across the face of a transducer B) Phased array- 2) Voltage pulses are applied to most or all elements as a group, but with small time differences C) Convex array - 1) Voltage pulses are applied in succession to groups of elements across the face of a transducer
front 48 If the elements of a phased array are pulsed in rapid succession from right to left, the resulting beam is ___________. A) steered right B) steered left C) focused	back 48 B) steered left

front 49 If the elements of a phased array are pulsed in rapid succession from outside in, the resulting beam is ___________. A) steered right B) steered left C) focused	back 49 C) focused
front 50 _____________ and _______________ describe how arrays are constructed. A) linear B) phased C) sequenced D) vector E) convex	back 50 A) linear E) convex
front 51 ____________, ___________, and ____________ describe how arrays are operated. A) linear B) phased C) sequenced D) vector E) convex	back 51 B) phased C) sequenced D) vector
front 52 Shorter time delays between elements fired from outside in results in ____________ curvature in the emitted pulse and a _____________ focus. A) no, weak B) less, shallower C) less, deeper D) greater, shallower E) greater, deeper	back 52 C) less, deeper

front 53 A rectangular image is a result of linear scanning of the beam. This means that pulses travel in ___________ _______________ direction from _____________ starting points across the transducer face.	back 53 The same, different
front 54 A sector image is a result of sector steering of the beam. This means that pulses travel in ___________ directions from a common _____________ at the transducer face.	back 54 different, origin
front 55 In ______________ and ____________ arrays, pulses travel out in different directions from different starting points on the transducer face.	back 55 convex, vector
front 56 Axial resolution is the minimum reflector separation required along the direction of the ___________ ___________ to produce separate ________________.	back 56 sound travel, echoes

front 57 Axial resolution depends directly on ___________ __________ ____________.	back 57 spatial pulse length
front 58 True or False? Smaller axial resolution is better.	back 58 True
front 59 If there are three cycles of a 1 -mm wavelength in a pulse, the axial resolution is ___________ mm.	back 59 1.5 mm SPL = 1 mm * 3 cycles = 3 mm 3 mm / 2 = 1.5 mm
front 60 For Pulse traveling through soft tissue in which the frequency is 3 MHz and there are four cycles per pulse, the axial resolution is ___________mm.	back 60 1 mm Λ = 1.540 / 3 = .531 mm SPL = .531 * 4 = 2.05 RL = 2.05 / 2 = 1.02

front 61 If there are two cycles per pulse, the axial resolution is equal to the ____________. At 5 MHz in soft tissue, this is _____________mm.	back 61 wavelength, .3 mm Λ = 1.540 / 5 = .308 mm SPL = .308 * 2 = .616 RL = .616 / 2 = .308
front 62 Doubling the frequency causes axial resolution to be ________.	back 62 halved
front 63 Doubling the number of cycles per pulse causes axial resolution to be ________________.	back 63 Doubled
front 64 True or False? When studying an obese subject, a higher frequency likely will required	back 64 False

front 65 True or False? If better resolution is desired, a lower frequency will help.	back 65 False
front 66 If frequencies less than __________ MHz are used, axial resolution is not sufficient.	back 66 2 Mhz
front 67 If frequencies higher than __________ MHz are used, penetration is not sufficient.	back 67 15 Mhz
front 68 Increasing frequency improves resolution because ___________ is reduced, thus reducing ____________ ___________ ___________.	back 68 wavelength, Spatial pulse length

front 69 Increasing frequency decreases penetration because _________ is increased.	back 69 attenuation
front 70 Lateral resolution is the minimum ___________ between two reflectors at the same depth such that when a beam is scanned across them, two separate __________ are produced.	back 70 separation, echoes
front 71 Lateral resolution is equal to __________ ____________ in the scan plane.	back 71 beam width
front 72 Lateral resolution does not depend on _____________. A) frequency B) aperture C) phasing D) depth E) dampening	back 72 E) dampening

front 73 True or False? For an aperture of a given size, increasing frequency improves lateral resolution.	back 73 True
front 74 True or False? Lateral resolution varies with distance from the transducer.	back 74 True
front 75 True or False? For a given frequency, a smaller aperture always yields improved lateral resolution.	back 75 False in general - only true near transducer
front 76 Lateral resolution is determined by: A) dampening B) frequency C) aperture D) number of cycles in the pulse E) distance from the transducer F) focusing	back 76 B) frequency C) aperture E) distance from the transducer F) focusing

front 77 Match the following transducer assembly parts with the functions: A) Cable B) Dampening material C) Piezoelectric element D) Matching layer 1) Reduces reflection at transducer surface 2) Converts voltage pulses to sound pulses 3) Reduce pulse duration 4) Converts voltage pulses	back 77 A) Cable - 4) Converts voltage pulses B) Dampening material - 3) Reduce pulse duration C) Piezoelectric element - 2) Converts voltage pulses to sound pulses D) Matching layer - 1) Reduces reflection at transducer surface
front 78 Which of the following improve sound transmission from the transducer element into the tissue? A) Matching layer B) Doppler effect C) dampening material D) coupling medium E) refraction	back 78 A) Matching layer D) coupling medium
front 79 A 5 -MHz unfocused transducer with an element thickness of .4 mm, an element width of 13 mm, and a near-zone length of 14 cm produces two-cycle pulses. Determine the following A) Operating frequency if thickness is reduced to .2 mm: ___________ MHz B) Axial resolution in the case of a: __________ mm C) Depth at which lateral resolution is best: ________ cm D) Lateral resolution at 14 cm: _________ mm E) Lateral resolution at 28 cm: _________ mm F) This transducer can be focused at depths less than __________ cm.	back 79 A) 10 B) .15 C) 14 D) 6.5 E) 13 F) 14 A) If thick halved, fo is doubled 2 * 5 MHz = 10 MHz B) SPL = nc/f (2 * 1540 m/s) / 10 MHz 3080 m/s / 10 MHz = .308 Axial = ½ * SPL = .5 * .308 = .154 D) RL = beam width = Focus width ½ e.width .5 * 13 = 6.5
front 80 Lateral resolution is improved by _____________. A) dampening B) pulsing C) focusing D) matching E) absorbing	back 80 C) focusing

front 81 For an unfocused transducer, the best lateral resolution (minimum beam width) is ____________ the transducer width. This value of lateral resolution is found at a distance from the transducer face that is equal to the _________________ ______________ length.	back 81 half, near-zone
front 82 For a focused transducer, the best lateral resolution (minimum beam width) is found in the __________ region.	back 82 focal
front 83 An unfocused 3.5-MHz, 13-mm transducer will yield a minimum beam width (best lateral resolution) of ________ mm.	back 83 6.5 mm ½ * 13 mm
front 84 An unfocused 3.5-MHz, 13-mm transducer produces three-cycle pulses. The axial resolution in soft tissue is ___________ mm.	back 84 .7 mm SPL = nc/f (3 * 1.540) / 3.5 4.62 / 3.5 = 1.320 ½ SPL = 1.320 * .5 = .66

front 85 True or False? An unfocused 3.5-MHz, 13-mm transducer produces three-cycle pulses, will yield a minimum beam width (best lateral resolution) of 6.5 mm. The axial resolution in soft tissue is .7 mm. Axial resolution is better than lateral resolution.	back 85 True
front 86 True or False? Axial resolution is often not as good as lateral resolution in diagnostic ultrasound.	back 86 False
front 87 The two resolutions may be comparable in the ____________ region of a strongly focused beam.	back 87 Focal
front 88 True or False? Beam diameter may be reduced in the near zone by focusing	back 88 True

front 89 True or False? Beam diameter may be reduced in the far zone by focusing.	back 89 False
front 90 Match each transducer characteristic with the sound beam characteristic it determines A) Element thickness B) Element width C) Element shape D) damping 1) Axial resolution 2) lateral resolution 3) operating frequency	back 90 A) Element thickness - 1) Axial resolution, 2) lateral resolution, 3) operating frequency B) Element width - 2) lateral resolution C) Element shape - 2) lateral resolution D) Damping - 1) Axial resolution
front 91 The principle on which ultrasound transducers operate is the _______________. A) Doppler effect B) Acousto-optic effect C) Acousto-electric effect D) cause and effect E) piezoelectric effect	back 91 E) piezoelectric effect
front 92 Which of the following is not decreased by damping A) refraction B) pulse duration C) spatial pulse length D) efficiency E) sensitivity	back 92 A) refraction

front 93 Which three things determine beam diameter for a disk transducer? A) pulse duration B) frequency C) aperture D) distance from disk face E) efficiency	back 93 B) frequency C) aperture D) distance from disk face
front 94 True or False? A two-cycle pulse of 5-MHz ultrasound produces separate echoes from reflectors in soft tissue separated by 1 mm.	back 94 True axial resolution .3 mm SPL = (nc)/f (2 * 1540) / 5 3080 / 5 = .616 ½ SPL = .5 * .616 = .308 mm 1 mm > .3 mm
front 95 The lower and upper limits of the frequency range useful in diagnostic ultrasound are determined by ___________ and ___________ requirements respectively.	back 95 resolution, penetration
front 96 The range of frequencies useful for most applications of diagnostic ultrasound is ____________ to __________ MHz	back 96 2, 15

front 97 Because diagnostic ultrasound is usually two or three cycles long, axial resolution is usually equal to ___________ to __________ wavelength	back 97 1, 1.5
front 98 What is the axial resolution A-B? A - An image of a set of six rods in a test obeject. They are separated by 5, 4, 3, 2, and 1 mm from top to bottom. This scan was made using a transducer that produces 3.5-MHz ultrasound. The first three rods have been separated, whereas the images of the last three rods have merged. This image also shows small reverberation echoes behind each rod. B - The same rods image with a 5-MHz transducer. Higher-frequency transducer produce shorter pulse lengths and therefore provide improved axial resolution.	back 98 3 mm, 2 mm
front 99 At what depth is the best lateral resolution C? Beam diameter for 6-mm, 5-MHz transducer C - A focused beam. This is an ultrasound image of a beam profile test object containing a thin vertical scattering layer down the center. Scanning this object generates a picture of the beam (pulse width at all depths) In this case, the focus occurs at a depth of about 4 cm ( this image has a total depth of 15 cm) Depth markers (in 1-cm increments) are indicated on the left edge	back 99 4 cm
front 100 Match the transducer type with the display formats A) Linear array - 1 B) convex array - 4 C) phased array - 3 D) vector array - 5 E) phased linear array - 2	back 100 A) Linear array - 1 B) convex array - 4 C) phased array - 3 D) vector array - 5 E) phased linear array - 2