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217 Cards in this Set
- Front
- Back
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What the patient does to sound, is called? |
Acoustic Propagation Properties |
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What the wave does to the patient, is called? |
Biologic Effects *small tissue heating |
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True/False: Sound is always affected by the patient, the patient is always affected by the sound. |
True |
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Sound waves require a _____________ to propagate. |
medium |
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What are the 3 "Bigness Parameters" |
Amplitude (pascals, g/cm cubed, meters) Power (watts) Intensity (watts/cm sqd) |
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Amplitude, Power, and Intensity all have a _______________ relationship. |
direct |
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True/False: Amplitude, Power and Intensity can all be adjusted by the Sonographer. |
True |
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The distance that energy travels during one cycle is called? |
Wavelength (cm,mm) |
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A cycle per second is called? |
Frequency (Hz) |
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How long it takes to complete one cycle is called? |
Period (sec) |
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Another name for Velocity is? |
Propagation Speed (m/s) |
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Period, Frequency, Amplitude, Power, and Intensity are all determine by? |
Source |
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Wavelength is determined by? |
Source and Medium |
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Propagation Speed is determined by? |
Medium |
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True/False: Period, Frequency, Wavelength, Propagation Speed are not adjustable by the Sonographer. |
True |
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Speed of sound in tissue is? |
1,540 m/s 154,000 cm/s 1.54 km/s |
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The time that a pulse is 'on', is called? |
Pulse duration (microseconds) *talk time of the PRP |
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The distance of the pulse end to end, is called? |
Spatial Pulse Length (mm) *beginning to the end of the pulse |
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The time from the start of one pulse to the start of the next pulse, is called? |
Pulse Repetition Period (sec) *two parts: -talk time -listen time *the deeper you go, the longer you listen |
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The number of pulses that an ultrasound system transmits into the body each second, is called? |
Pulse Repetition Frequency (Hz) *pulses per second (includes listening time) |
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The percentage or fraction of time that the system transmits a pulse, is called? |
Duty Factor (%) * typical DF for pulse imaging = <1% |
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True/False: Pulse duration and Spatial Pulse Length are not adjustable by the Sonographer. |
True |
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True/False: PRP, PRF and Duty Factor are adjustable by the Sonographer. |
True *when we change our depth, we change the duty factor |
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Pulse Duration, PRP, PRF and Duty Factor are all determined by the? |
Source |
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Spatial Pulse Length is determined by? |
Source and Medium |
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Why do we pulse sound? |
to image *to know where image came from and display it |
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What are the 3 factors of Attenuation? |
Reflection Scattering Absorption |
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Name the 3 key components of the Ultrasound Transducer. |
Backing Material Piezo-electric element (crystal) Matching Layer |
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True/False: Diffuse reflections are where we get most of our information from. |
True |
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Name the 2 types of reflections. |
Specular (smooth) Diffuse (rough + backscattering) |
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Absorption turns into _________. |
heat *sound turns into heat |
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What is the biggest Attenuator? |
Absorption *90% of loss is due to absoprtion |
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Name the 2 types of Scattering. |
Rayleigh (uniform)(reflects equally in all directions) Scattering (reflects randomly in many different directions) |
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The piezoelectric element converts ______________ into _______________ and vice versa. |
sound into electricity electricity into sound *part of the transducer that does the transducing |
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Which transducer element increases (improves) the efficiency of sound energy transfer between the active element and the body? |
Matching layer *protect the active element (pzt) |
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Which transducer element steps up and steps down the impedance? |
Matching layer (lower than PZT, higher than soft tissue)(vice versa) *PZT-> matching layer-> gel-> skin (vice versa) |
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What are the main things that the backing layer of the transducer helps with or hinders? (4) |
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Name the 5 key parts of the ultrasound beam. |
Near Zone (converging) Focal length/Near zone length Focus Focal Zone Far Zone (diverging) |
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Each individual sound beam can only have ________ focus. |
one |
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Complete the Chart: Depth__________PRP__________ PRF 8 cm____________?___________ 2KHz 16 cm___________?_____________ ? |
Depth__________PRP__________PRF 8cm____________1/2ms_______ 2Khz 16 cm__________1ms_________1KHz |
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Which part of the sound beam is the image best? |
Focal Zone |
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Which part of the sound beam is narrowest? |
Focus |
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To create an ultrasound image, it requires ___________ sound pulses. |
multiple |
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Name the 3 modes of display. |
Amplitude Mode (A-mode) Brightness Mode (B-mode) Motion Mode (M-mode) |
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Which mode is always a graph that has a series of uphill spikes? |
A-mode |
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True/False: A-mode, B-mode and M-mode are never an anatomical image, they are always a graph. |
True *but they can be superimposed on the same screen as an image |
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In M-Mode, ________________ is on the vertical axis, and _________________ is on the horizontal axis. |
depth (vertical axis) time (horizontal axis) |
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A ___________________ transducer has a fixed focus and is __________________ steered. |
Mechanical mechanically steered |
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Which transducer has all of the elements in the array are turned on at the same time for every pulse, but with slight delays? |
Phased transducer *we steer and focus at the same time *adjustable and multi-focus |
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What is the deepest place that a transducer can focus? |
Natural focus |
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All electronic focusing is done in the ___________ field. |
near field |
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True/False: 2D images are made from multiple sound pulses. |
True |
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Which type of Array turns on the elements (pulses) in an array as a group, waits for those echo's to be sent/received, and then turns on and sends the next group out.
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Linear Sequential Array transducer |
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________________ is always adjustable or multi-focus, and allows us to steer and focus at the same time. |
Phasing |
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The _______________ tells us which way we are steering, the ________________ tells us how superficially we are pulsing. |
Slope Curvature |
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True/False: ALL electronic focusing is done in the Near field. |
True |
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The greater the curvature of a beam, the _______________ superficial the focus. |
more |
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Need determine the slope line for ________________, and ________________ for focal depth of a sound beam. |
steering (slope line)
curvature (focal depth) |
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When there is no slope or curvature we are at the ________________ of a sound beam. |
Natural focus *steering straight ahead *no curvature = we are as deep as that transducer will focus |
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If any adjustments are made to the focus of a sound beam, it will put a _______________ , electronically bringing the focus up into the near field. |
curvature |
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True/False: Anytime there is a curvature, the focus is brought up into the near field from the natural focus. |
True *electronically brought up more superficial |
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True/False: We can focus to different depths without changing the transducer. |
True |
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__________________ requires multiple sound pulses along the exact same scan line. |
Multi-focus *more sound pulses needed for multi-focus *sharpens up image |
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The ________________ Phased Array transducer, is the only one that is mechanically steered and electronically focused. |
Annular Phased Array transducer |
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A Linear Sequential Array transducer has a(n) ______________ focus. |
fixed focus *can be multi-focus only if phasing is added (adjustable focus) |
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A Linear Sequential Phased Array transducer has a(n) ___________________ focus. |
adjustable focus *because it is phased *aka Vector Array |
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A Linear Sequential Phased Array is also known as a __________________ Array. |
Vector Array transducer |
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Which type of transducer produces an image shape of a blunted sector. (3) |
Convex Array transducer (aka curved, curvilinear) |
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Mechanical transducer
Phased Array transducer Annular transducer |
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Which type of transducer produces a rectangular image shape? |
Linear Sequential transducer |
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Which type of transducer produces a trapezoidal (flat top) shaped image? |
Vector transducer |
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Which 2 types of transducer have mechanical steering? |
Mechanical transducer Annular Phased transducer |
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Which 4 types of transducer have electronic steering? |
Linear Sequential transducer Phased Array transducer Convex transducer Vector transducer |
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True/False: All transducers, EXCEPT Mechanical, use electronic focusing. |
True *mechanical transducer has a fixed focus |
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A ___________________ transducer has one crystal. |
Mechanical transducer |
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A ________________, ___________________, and ___________________ Array transducers have multiple crystals. |
Linear Array transducer Convex Array transducer Phased Array transducer |
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Which type of transducer will result in a loss of the entire image due to a malfunction of it's active element? |
Mechanical transducer (one crystal) |
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Which type(s) of transducer will result in a dropout of image information from the top to the bottom of the image due to an active element malfunction? (2) |
Linear Array transducer Convex Array transducer |
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Which type of transducer has erratic steering and focusing due to an active element malfunction? |
Phased Array transducer |
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Which type of transducer has a horizontal (side-to-side) dropout of information due to an active element malfunction? |
Annular Array transducer |
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True/False: Unless we have a 2D Array, we do not focus in the Slice Thickness/Elevation dimension (3D). |
True |
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We only focus in the ___________________ dimension. |
lateral dimension |
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How do we get rid of Side lobes or Grating lobes of a beam? |
Apodization (varies the voltage) Subdicing (cuts crystals into smaller parts) |
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True/False: It takes multiple sound pulses to create a frame (images). |
True |
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____________________ Resolution is "accuracy in time", the frame rate per second. |
Temporal Resolution (real time/live) |
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The way we put a number to Temporal Resolution is _____________ ____________. |
frame rate |
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If you have good Temporal Resolution, you have a ______________ frame rate. |
high *poor temporal resolution, low frame rate |
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What 2 things effect our frame rate? |
imaging depth (scan depth) number of pulses per image (frame) |
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The more pulses needed, the ____________ Temporal Resolution, the _________________ Spatial Resolution. |
poorer (temporal resolution) better (spatial resolution |
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Which 3 factors determine the number of pulses needed to create an image? |
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If we increase the number of pulses needed to create an image, Temporal Resolution ________________ and Spatial Resolution ________________. |
decreases (temporal resolution) improves (spatial resolution) |
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If we increase the number of multi-focus points, Temporal Resolution _________________ and Spatial Resolution _________________. |
decreases (temporal resolution) improves (spatial resolution) |
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The narrower the sector, the ______________ the pulses, the _____________ the Temporal Resolution. |
fewer (pulses) better (temporal resolution) |
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The wider the sector, the ______________ pulses, the ______________ the Temporal Resolution. |
more (pulses) poorer (temporal resolution) |
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Sector size and Temporal Resolution have a _____________ relationship. |
indirect |
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Temporal Resolution and the number of pulses needed, have a ________________ relationship. |
indirect |
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Spatial Resolution and the number of pulses needed, have a _________________ relationship. |
direct |
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True/False: We can change the sector size without effecting (changing) the Spatial Resolution. |
True
*making an image wider/narrower does not change spatial resolution |
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As line density increases, Temporal Resolution ______________, Spatial Resolution ______________. |
decreases (temporal resolution) improves (spatial resolution) |
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The more pulses, the ______________ the Temporal Resolution, the _______________ the Spatial Resolution. |
poorer (temporal resolution) better (spatial resolution) |
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The fewer the pulses, the _________________ the Temporal Resolution, the _________________ the Spatial Resolution. |
better (temporal resolution) degraded (spatial resolution) |
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Name the 3 acoustic variables. |
Pressure (pascals, psi, mmHg) Density (kg/cm cubed) Distance (cm, mm) |
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All sound waves are ________________ waves, and ____________________ waves. |
longitudinal waves mechanical waves |
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Electromagnetic waves are _________________ waves. |
transverse waves |
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___________________ interference takes place with In-phase waves. |
Constructive interference |
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___________________ interference takes place with Out-of-phase waves. |
Destructive interference |
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True/False: All waves are a transfer of energy and have a form of interference. |
True |
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True/False: Sound waves will not propagate in space, electromagnetic waves will. |
True |
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What is the typical value range of Frequency for Continuous waves? |
2 - 15 MHz (2-10 MHz) *frequency (diagnostic ultrasound) = MHz *PRF = KHz |
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True/False: Period and Frequency are reciprocals. |
True |
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How does the Sonographer adjust the Power, Amplitude and Intensity? |
adjusting the depth *you can also adjust the power, amplitude and intensity w/out changing the depth |
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PRP, PRF and Duty Factor are adjusted exclusively by changing the _______________. |
depth |
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Equation: Wavelength = |
propagation speed (m/s) / frequency (Hz) |
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True/False: Amplitude and Power have a SQUARE relationship. |
True *if amplitude doubles, power goes up by a factor of 4 |
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Amplitude, Power and Intensity have a _____________ relationship. |
direct |
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What is the units for Pulse Repetition Frequency? |
KHz |
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True/False: PRP increases with depth. |
True *the deeper the scan, the longer period (talk/listen time) |
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PRP and PRF have a _____________ relationship. |
reciprocal relationship *if depth increases, PRP increases, PRF decreases |
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PRP and Duty Factor have a ___________________ relationship. |
reciprocal relationship *If depth increases, PRP increases, Duty factor decreases |
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If the depth of scan increases, the Duty Factor _________________, and the PRF _______________. |
decreases decreases |
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If depth increases, PRP ________________, and Duty factor ______________. |
increases (PRP) decreases (PRF) |
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If depth decreases, PRP _____________, and Duty factor _______________. |
decreases (PRP) increases (duty factor) |
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What is the typical value range of PRF for Pulsed waves? |
1 - 10 KHz PRF = KHz |
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What are the Temporal Intensities from largest to smallest? (5) |
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True/False: SPTA is associated with Bio Effects. |
True *what the wave does to the patient (different intensities) |
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What does 0 dB mean? |
input equals output |
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What does 3 dB mean? |
doubled |
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What does 10 dB mean? |
ten times larger |
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What does - 3 dB mean? |
half |
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What does - 10 dB mean? |
one-tenth |
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An increase in 100 x, what is that in dB? |
20 dB 100 times = 20 dB |
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If there is a decrease in 40 dB, how many times did it decrease? |
10,000 10^4 = 10,000 |
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True/False: Attenuation is always a loss. |
True |
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Specular reflections are very ______________ dependent but strong. |
angle |
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As the frequency increases, the wavelength __________________, stuff looks rougher and diffuse reflections __________________. |
decreases (wavelength) increase (diffuse reflection) |
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Frequency and wavelength have a __________________ relationship. |
reciprocal |
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Frequency and Diffuse reflection have a ____________________ relationship. |
direct |
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True/False: Reflections and Scattering are very Frequency dependent. |
True |
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As the Frequency increases, Diffuse reflection and Scattering will _________________. |
increase |
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What is the conversion from sound to heat called? |
Absorption *very frequency dependent |
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Total Attenuation is dependent upon which 2 factors? |
path length frequency |
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The deeper the scan the _____________ the path length, the ________________ the Attenuation. |
longer (path length) greater (attenuation) |
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The higher the frequency, the _________________ the Attenuation. |
greater (attenuation) |
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Equation: Impedance (rayls)= |
Density x Propagation Speed (m/s) |
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What determines how much reflection and transmission there is once the sound beam reaches a boundary? |
Impedance *When you come to a boundary, what kind of Impedance difference do you have? The type of medium is not very important, it is just how that specific medium compares to the next medium. |
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If there is a large Impedance difference, there will be a _______________ reflection. |
large (reflection) |
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What are the 2 angles of measure used for Incidence? |
90 degree (right angle) (perpendicular) oblique angle |
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What is the angle at which the wave strikes the boundary called? |
Incidence |
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What are the synonyms for Normal Incidence? |
Perpendicular Orthogonal Right angle Normall Ninety degrees *PORNN |
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True/False: Energy is always conserved. |
True |
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The sound wave's intensity immediately before it strikes a boundary is called? |
Incident Intensity |
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The intensity of the portion of the sound beam that returns back from where it came after striking the boundary, is called? |
Reflected Intensity |
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The intensity of the portion of the sound beam that continues forward after striking the boundary, is called? |
Transmitted Intensity |
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True/False: An Incident beam is always 100%, a certain percentage is reflected and the remaining is transmitted. |
True *reflection and transmission always equals 100% |
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The bigger the Impedance difference, the _____________ the reflection and the _____________ the transmission. |
bigger (reflection) smaller (transmission) |
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A small Impedance difference the ______________ the transmission and the _______________ the reflection. |
larger (transmission) smaller (reflection) |
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True/False: The Incidence beam and Reflected beam always have the same angle. |
True |
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If we have Oblique Incidence and different speeds on either side of the boundary, __________________ will occur. |
Refraction *different speeds+oblique incidence = refraction |
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True/False: A Transmitted beam is the only beam that ever Refracts. |
True |
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True/False: We measure the angle of the beam from the perpendicular. |
True *side w/ large angle = high speed *side w/ small angle = low speed |
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The side with the largest angle has the ______________ speed. |
greatest (speed) large angle = high speed small angle = low speed |
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The side with the smallest angle has the ____________________ speed, and the beam has turned back towards the perpendicular. |
lowest (speed) *small angle = low speed = turns toward perpendicular (x-axis) |
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The side with the largest angle has the _______________ speed, and the beam turns away from the perpendicular. |
greatest (speed) *large angle = high speed = turns away from perpendicular (x-axis) |
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Refraction is quantified by ____________ Law. |
Snell's Law |
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What tells us where the machine knows where to put reflector on display, how we determine depth? (3) |
Range Equation Distance Formula 13 Microsecond Rule |
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Using the 13 Microsecond Rule, if the time of flight is 13 microseconds, what is the reflector depth and the total distance traveled? |
1 cm (reflector depth) 2 cm (total distance traveled) |
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Using the 13 Microsecond Rule, if the reflector depth is 4 cm, what is the time of flight and the total distance traveled? |
52 microseconds (time of flight) 8 cm (total distance traveled) |
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The _______________________ effect turns electricity into sound, and sound into electricity. |
Piezoelectric Effect/Revere Piezoelectric Effect *the reason we only need one transducer |
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Clinical transducers use PZT material, which is? |
lead zirconate titanate |
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True/False: All imaging transducers are Low Q (quality). |
True |
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The transducer will be depolarized if heated above it's ____________ ____________. |
Curie point |
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How do we determine the frequency of a transducer for Continuous wave? |
Voltage frequency *whatever the voltage frequency is, is the sound frequency for continuous wave *Electrical frequency = Acoustic frequency *Voltage frequency = Sound frequency *Electrical frequency = Sound frequency |
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What are the 2 parameters for Pulse wave? |
Speed of sound in the PZT crystal Thickness of the PZT crystal |
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For Pulsed Wave, if the speed of sound in a PZT crystal is high, the frequency will be ________. |
High |
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For Pulsed Wave, the speed of sound in a PZT crystal has a(n) __________ relationship with frequency. |
direct |
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For Pulsed Wave, the thinner the PZT crystal, the _____________ the frequency. |
higher |
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For Pulsed Wave, the PZT crystal has a(n) ________________ relationship with frequency. |
inverse |
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For Pulsed Wave, the thicker the PZT crystal, the ____________ the frequency. |
lower |
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The sound beam always _________________ in the Near field, and __________________ in the Far field. |
converges (near field) diverges (far field) |
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The Focal zone straddles the _____________ of a sound beam. |
Focus |
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Which 2 factors determine Focal depth? |
Transducer diameter Frequency of sound *they also determine divergence in the far field |
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The larger the transducer diameter, the ______________ the frequency, the _____________ the focal length (depth) and the less the divergence. |
higher (frequency)
longer (depth) less (divergence) |
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The smaller the transducer diameter, the _______________ the frequency, the _______________ the focal length (depth) and the greater the divergence. |
lower (frequency) shorter (depth) greater (divergence) |
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The longer the focal length, the ______________ the divergence. |
less (divergence) |
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The shorter the focal length, the _______________ the divergence. |
greater (divergence) |
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Diffraction or spreading of the waves; wavelets combine into one sound pulse, is known as? |
Huygens' Principle |
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True/False: Axial resolution does not change when the sound pulse propagates. |
True
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Which type of resolution is parallel to the beam, (front-to-back) and images in the Near field and Far field are best with short pulses? |
Axial Resolution *LARRD |
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Which type of resolution is perpendicular to the sound beam (side-to-side) and images in the Near field are best with a small diameter crystal? |
Lateral Resolution *LATA |
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Which type of resolution has better images in the Far field with a larger diameter and higher frequency crystal? |
Lateral Resolution *LATA |
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Which type of resolution is determined by 1/2 of the Spatial Pulse Length? |
Axial Resolution *LARRD |
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Which type of resolution is determined by the BEAM width? |
Lateral Resolution *LATA |
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Which type of resolution is best with the shortest pulse, highest frequency and fewest cycles? |
Axial Resolution *LARRD |
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Which type of resolution is best with the narrowest BEAM width? |
Lateral Resolution *LATA |
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True/False: Axial Resolution does not change, it is the same at all depths. |
True *axial resolution is constant |
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True/False: Lateral Resolution changes with depth, and is best at the Focus. |
True *lateral resolution is continuously changing |
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What is the only display mode that provides information regarding reflector motion with respect to time? |
M-mode |
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With A-mode, what is displayed on the x-axis? |
depth of the reflector |
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With M-mode, what is displayed on the y-axis? |
depth of the reflector |
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Which mode provides the foundation for real-time, gray-scale anatomic imaging? |
B-mode (brightness mode) |
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With A-mode, what is displayed on the y-axis? |
amplitude of the reflected signal |
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In M-mode, what is displayed on the x-axis? |
time |
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With B-mode, which axis is related to the strength of the reflection? |
z-axis |
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True/False: Mechanical scanning produces pictures that are similar in shape to linear phased array images. |
True |
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True/False: Mechanical scanning and Linear phased arrays create sector-shaped images. |
True |
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True/False: Many active elements fire at almost the same time in a phased array scanner. |
True |
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Which of the following transducers is best described as mechanically steered and fixed, single focused? a) annular phased array b) annular array c) mechanical d) linear phased |
c) mechanical |
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Which of the following is best described as mechanically steered and multi-focus? a) annular phased array transducer b) annular sequential array transducer c) mechanical transducer d) linear phased transducer |
a) annular phased array transducer *no such thing as an annular sequential array transducer |
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Which of the following transducers creates a rectangular shaped image? a) annular phased array b) linear sequential array c) mechanical d) linear phased |
b) linear sequential array |
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A linear phased array transducer has 128 crystals. How many of these crystals are fired to create a single sound beam? a) 1 b) small group c) large group d) 128 |
d) 128 |
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True/False: A small group of active elements are fired to create each sound pulse. |
True |
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In a linear phased array, what is the firing pattern that steers a beam to the left or right? |
electronic slope |
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True/False: There are large time delays in the firing pattern of a linear phased array transducer. |
False *there are tiny time delays in the firing pattern of a linear phased array transducer |
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True/False: A machine that displays A-mode and two-dimensional images is called a duplex scanner. |
False *a machine that displays Doppler and two-dimensional images is called a duplex scanner |
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Which of the following improves elevational resolution? a) matrix array b) linear phased array c) one and one-half dimensional array d) two-dimensional array |
c) one and one-half dimensional array *creates a thin slice |
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True/False: Side lobes degrade axial resolution. |
False |
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True/False: Side lobes degrades lateral resolution. |
True |
