1.
0.05-0.5mm: what are the typical values for LAARD resolution?
2.
2-4: transducers are designed to have ______ cycles per pulse
3.
4-6 mm/ nano sec (us): what is the typical sound speed of a pulsed wave transducer
4.
adjustable or elctronic: what type of focusing has the best LATA resolution?
5.
approx 360 C or 680 F: what is the approximate numerical temperature for curie point?
6.
at focus only: where is lateral resolution optimal?
7.
at the end of the near zone: where is the sound beams diameter 1/2 half of the transducer aperature?
8.
axial resolution: the ability to distinguish two structures that are close to each other front to back (ant to post), parallel or along the beams axis
9.
bandwidth: what is the range of the number of frequencies between the highest and lowest frequency emitted from the transducer?
10.
bandwidth: max freq- min freq = ?
11.
barium titanate, lead metaniobate, lead titanate, lead zicronate titanate or PZT: what are the man made ferroelectric (piezoelectric) materials
12.
beam diameter (mm): lateral resolution (mm) = ?
13.
case: what protects the internal components and insulates patient from shock?
14.
ceramic, active element or crystal: PZT is also called?
15.
change to transducer with a shorter pulse or to a transducer with a higher frequency: how do we produce shorter pulses?
16.
continuous wave and therapeutic: what kinds of transducers do not require damping material?
17.
continuous wave and therapeutic transducers: imaging transducers have a lower Q factor and a wider bandwidth than what?
18.
continuous wave transducer: the frequency of the voltage is applied to the crystal by the systems electronics, equals the sound waves frequency for what kind of transducer?
19.
conventional and mechanical: what are the other names for fixed focus
20.
curie point (or curie temperature0: what is the temperature at which PZT is polarized to attain piezoelectric properties called?
21.
damping element (backing material): rubber material that is attached to the back side of the active element that limit's the ringing of the PZT
22.
damping element (backing material): what is made of epoxy resin impregnated with tungsten?
23.
deeper: the bigger the transducer diameter, the ______ the focus
24.
deeper: the higher the frequency , the _____ the focus
25.
depolarized forever: what happens if a PZT is heated above curie point?
26.
directly: how is sound speed related to frequency in a pulsed wave transdcuer?
27.
disinfection: refers to the application of a chemical agent to reduce or eliminate infectious organisms on an object (txdr); killing of bacteria
28.
during reception: when does the piezoelectric effect occur?
29.
during transmission: when does reverse piezoelectric effect occur?
30.
external (lens), internal (curved PZT crystal) and adjustable or electronic focus: what are the 3 types of focus
31.
far zone: region or zone beyond the near zone
32.
far zone: aka Fraunhofer zone
33.
far zone: where do sound beams diverge?
34.
focal depth: aka focal length or near zone length
35.
focal depth: the distance from the transducer face to the focus
36.
focal zone: region or zone surrounding the focus where the beam is narrow and the image is relatively good
37.
focus (focal point): the location where the sound beam reaches it's minimum diatmeter; also the point of maximum intensity
38.
Huygen's principal: principle stating that one large PZT is made up of multiple tiny PZT's each producing a diffraction pattern where waves interfere and produce and hour glass shaped beam
39.
Huygen's wavelet: diffraction described as v- shaped or spherical waves
40.
inversely: how are thickness of crystal and frequency related in a pulsed wave transducer?
41.
inversely: how are diameter and frequency related to far zone (divergence)?
42.
inversely: how are dampening and quality factor related?
43.
inversely: how is focusing related to focal zone?
44.
it can not accurately differentiate: what happens when the beam width is wider than the distance between reflectors?
45.
Lateral resolution: measure's detail in an image
46.
lateral resolution: can distinctly identify two structures that are side by side or perpendicular
47.
lateral, angular, transvers, azimuthal: what does LATA stand for (lateral resolution)
48.
Longitudinal, axial, range, radial and depth: what does LAARD stand for? (axial resolution)
49.
Low "Q": are imaging trandsducers high or low "Q"?
50.
low number: what kind of numbers do we want to accurately image reflectors that are very close together?
51.
matching layer: what is 1/4 wavelength thick
52.
matching layer: portion of the transducer between crystal and skin; decreases reflections at PZT and skin boundary allowing more sound to enter the body
53.
mm, cm, etc. (distance): resolution is measured in units of?
54.
narrower waist, decreased focal depth and a reduction in size of focal zone: focusing results in what?
55.
natural frequency, primary, resonant and center: the main frequency emitted by the transducer is also called what? (4 names)
56.
near zone: the region or zone between transducer and focus
57.
near zone: aka Frensel zone
58.
near zone: where do sound beams converge?
59.
No: should transducers be sterilized using dry or moist heat?
60.
No (they melt): can we heat sterilize or autoclave (pressure heat) transducers?
61.
Phased array: adjustable focusing or multi focusing is called what?
62.
piezoelectric effect: describes a property of certain materials to create an electrical voltage when they are mechanically deformed (when pressure is applied)
63.
piezoelectric effect during reception: reflected sound pulse is received by transducer causing crystal to vibrate and electricity is created
64.
pulsed wave transducers: what transducer is determined by propagation speed and the thickness of the crystal?
65.
PZT (active element, crystal): what is 1/2 the pulse's wavelength thick?
66.
PZT, case, wire, matching layer and damping element: what are the 5 key elements of a transducer?
67.
PZT, matching layer, gel, skin: what is the decreasing order of impedances ?
68.
Q factor: center frequency (MHz) / Bandwidth (MHz) =
69.
Q factor: the number o fcycles in a pulse of an imaging transducer is aprox the same as what?
70.
Quality factor (Q factor): unitless number representing the degree of dampening
71.
quarts, rochelle salts, and tourmaline: what are the natural ferroelectric (piezoelectric) materials
72.
radiofrequency shield: what reduces noise level and enhances sensitivity to weak signals?
73.
radiofrequency shield: what is placed around the crystal and backing material to reduce the electromagnetic interference?
74.
resolution: the ability to image acurately
75.
reverse piezoelectric effect during transmission: voltage to transducer causing the crystals to vibrate and sound energy is created
76.
shortens SPL, shortens pulse duration and decreases transducer sensitivity: what are damping element characteristics? (3)
77.
shorter pulses, less divergence in far feild, narrower beams in far feild, high frequency improves image: what are the advantages of using high frequency pulsed sound?
78.
single crystal transducers: what type of transducers are always fixed?
79.
smaller: short pulses produce _______ numerical values for LAARD resolution
80.
sterile probe cover: what is used for proper sterile techinque
81.
sterilization: the complete destruction of all living microorganism by means of exposure to heat, chemical agents or radiation
82.
T-spray and Cidex gluterdehyde: what cold germicides are used on transducers?
83.
thickness of the crystal: in pulsed wave transducers, what is half the wave lenght?
84.
transducer: what converts one form on energy to another?
85.
transducer diameter and frequency: focal depth is determined by what 2 factors?
86.
ultrasound transducer: what converts electrical energy into sound (acoustic) energy
87.
wider: US pulses are ____ than they are short
88.
wire: what is needed for transmission and reception; one for each crystal?
