# Shared Flashcard Set

## Details

DMSO 1080 reg.prep
PASS BOOK FINAL EXAM
129
Physics
10/29/2015

Term
 Transducer frequency is directly proportional to:
Definition
 sound intensity
Term
 Which is not considered an acoustic variable?
Definition
 intensity
Term
 If the density of the medium increases the speed of sound will:
Definition
 decrease
Term
 If the intensity of a signal is doubled what is the affect on amplitude:
Definition
Term
 which statement most correct about power?
Definition
 power is the rate of work
Term
 The percentage of time the sound is on is referred to as the:
Definition
 duty factor
Term
 The log of 10,000 is equal to:
Definition
 4
Term
 Which statement about intensity is most correct:
Definition
 intensity depends upon both power and beam area
Term
 If the initial is 40n and there is a 3dB gain the final intensity is:
Definition
 80
Term
 The speed of sound in tissue is
Definition
 1.54 mm/us
Term
 If the stiffness of a medium increases the propagation speed will:
Definition
 increase
Term
 A complete cycle consists of one compression and one rarefaction. The area of low pressure and density is referred to as:
Definition
 rarefaction
Term
 At one (1) half intensity depth
Definition
 the initial intensity was halved
Term
 Which of the following intensities would be the greatest for a pulsed beam of sound?
Definition
 SPTP
Term
 The attenuation coeffiecent for soft tissue is equal to ______ db/cm per MHz of frequency
Definition
 0.5-1.0
Term
 The units for impedence are:
Definition
 rayls
Term
 The decibel notation is a convenient way to express the ______ between two intensities
Definition
 ratio
Term
 The attenuation coefficient is expressed in:
Definition
 dB/cm/MHz
Term
 The most effective crystal thickness is ____ the wavelength
Definition
 1/2
Term
 Which of the following in NOT a purpose of the matching layer?
Definition
 create smooth interface with patient for safety, comfort and easy movement
Term
 The Fraunhofer Zone is also known as the:
Definition
 far field
Term
 Regarding Beam Formation what occurs in the Fraunhofer zone?
Definition
 increased attenuation and difraction
Term
 The near zone length is determined by:
Definition
 transducer frequency wavelength cyrstal diameter
Term
 Lateral resolution is also known as:
Definition
 LATA
Term
 Axial resolution is determined by:
Definition
 spatial pulse length
Term
 Which statement about harmonics is least correct?
Definition
 harmonics results because the compressed tissue propagation is slower than the strectched or rarefaction tissue
Term
 Which statement about the advantage of Matrix array tranducers is least correct?
Definition
 are mechanically steered and electronically phased
Term
 Dynamic Aperture changes the area of the crystal or number of elements that ate receiving the returning echoes to:
Definition
 create uniform laterla resoultion throughout the imaging depth both in the near field and far field
Term
 The round trip pulse travel time and distance to the reflector can be determined by using the:
Definition
 Range equation
Term
 The percentage of time the sound is on is called:
Definition
 duty factor
Term
 Which is NOT a function of the receiver?
Definition
 apodization
Term
 What are units for duty factor?
Definition
 none (unitless)
Term
 Which is an example of post-processing?
Definition
Term
 The turning of negative voltages into positive ones is a process called:
Definition
 rectification
Term
 The echoes are stored before final display by the:
Definition
 scan converter
Term
 Which is NOT an advantage of A-mode?
Definition
 calibration
Term
 All three display modes (A,B, & M-mode) have which of the following in common?
Definition
 range equation
Term
 The portion of the ultrasound system that stores the image before it is displayed is called:
Definition
 scan converter
Term
Definition
 signal integrity
Term
 The number of bits in the memory bit depth determines how many shades of gray in an image. TRUE or FALSE
Definition
 TRUE
Term
 The ultrasound echo signals that comes form the transducer are converted to a digital format in the:
Definition
Term
 A digital scan converter matrix 6 bit depth produces ____ shades of gray.
Definition
 64
Term
 In the memory, the equivalent to a prixel is the:
Definition
 bit
Term
 Most displays devices have approximately what dynamic range?
Definition
 20-30 dB
Term
 Which statement about potential energy is least correct?
Definition
 same as kinetic energy
Term
 As the vessel lumen size decreases, blood flow velocity will:
Definition
 increase
Term
 The inverse relationship between pressure and velocity is described by
Definition
 Bernoulli's equation
Term
 A high Reynold's number indicates _____ flow.
Definition
 turbulent
Term
 When tissue pressure exceeds intramural pressure, the veins will:
Definition
 compress
Term
 If the right artial pressure or central venous pressure is increased the veins in the body usually are:
Definition
 dilated
Term
 Which statement about Hydrostatic pressure is least correct?
Definition
 calf pump always reduces hydrostatic pressure
Term
 All of the following conditions will elevate right heart pressure except:
Definition
 mitral regurgitation
Term
 The factor(s) affecting the blood flow within the body include
Definition
 density of the blood velocity of flow size of the vessel
Term
 What angle provides the maximum Doppler shift?
Definition
 0 degrees
Term
 Continuous wave Doppler utilizes ________ elements.
Definition
 two
Term
 The range of Doppler shift frequencies are:
Definition
 20 - 20,000 Hz
Term
 The Nyquist limit is equal to _______ pf PRF
Definition
 1/2
Term
 Aliasing is a diagnostic for severe disease. TRUE or FALSE
Definition
 FALSE
Term
 The color assigned to flow towards the transducer is:
Definition
 red
Term
 The type of processing utilized with most color flow systems is:
Definition
 autocorrection
Term
 On color flow imaging, the best way to overcome aliasing is:
Definition
 use a high PRF number
Term
 The color priority on color flow instruments is used to:
Definition
 decide the relative contribution of color/echoes on the image
Term
 The color map represent the:
Definition
 mean Doppler shifts only
Term
 Aliasing is found in all of the following imaging modes except:
Definition
 CW doppler
Term
 PWD instruments are characterized because of their ability to do all of the following except:
Definition
 no alaising or velocity limits
Term
 The method used by CW Doppler to discriminate valuable signals is the
Definition
 zero crossing detector
Term
 In Doppler systems, changing the PRF is equal to changing the:
Definition
 velocity scale
Term
 An artifact that appears as multiple reflections equally spaced is called:
Definition
 reverbaration
Term
 Color mirror image artifacts can be eliminated by:
Definition
 decreasing output power
Term
 Enchancement occurs when the sound beam travels through a region of ______ than the surrounding tissue.
Definition
 lower attenution
Term
 The type of test object that evaluates sample gate accurancy and registration is the
Definition
 string test object
Term
 Quality assurance test for evaluating the lateral resolution and beam width would ultilize the rods in Group
Definition
 C
Term
 The term used to describe a procedure or test determining that a person does not have disease is:
Definition
 specificity
Term
 The ALARA principle relates to:
Definition
 Both minimum output and minimum exposure
Term
 The method of identifying and measuring the parts of the ultrasound that have the potential for producing bioeffects is called:
Definition
 dosimetry
Term
 which statement about higher frequencies is most correct?
Definition
 does not affect the propagation speed
Term
 Transducer frequency is directly proportional to:
Definition
 sound intensity
Term
 As an ultrasound wave travels through the body, its intensity usually:
Definition
 decreases
Term
 which statement about higher frequencies is most correct?
Definition
 does not affect the propagation speed
Term
 which condition between two media interfaces would produce the greatest amount of ultrasound reflected back to the transducer
Definition
 large impedance difference
Term
 Refraction often causes a type of artifact known as:
Definition
 lateral position error
Term
 The most effective crystal thickness is ____ the wavelength
Definition
 1/2
Term
 The optimal matching layer thickness is ____ the wavelength
Definition
 1/4
Term
 which statement about dicing & sub-dicing of the elements in a transducer is most correct:
Definition
 A) provides seperation to eliminate "cross-talk" between elements B) reduces the amount of off-axis energy that causes grating-lobesC) the optimum seperation for most applications is 1/2 the crystal wavelength or lessD) all of these
Term
 The largest range of output intensities is seen with:
Definition
 A) imagingB) pulsed dopplerC) color doppler imagingD) combination of all three
Term
 The echoes are stored before final display by the:
Definition
 scan converter
Term
 Which result is most correct if the scan line density is halved:
Definition
 frame rate will double
Term
 The number of pulses per second is referred to as:
Definition
 pulse repetition frequency
Term
 Line density for a given transducer is determined by:
Definition
 A) number of elementsB) number of channelsC) footprint of transducerD) all of these
Term
 The portion of the ultrasound system that stores the image before it is displayed is called:
Definition
 scan converter
Term
Definition
 signal integrity
Term
 What refresh rate do most high resolution monitors have?
Definition
 60
Term
 The difference between the transmit frequency and the received frequency is called the:
Definition
 Doppler shift
Term
 The angle corrector is used to:
Definition
 align the ultrasound beam with vessel lumen
Term
 PWD instruments are characterized because of their ability to do all of the following except:
Definition
 no alaising or velocity limits
Term
 Multipath artifacts are caused by the sound beam interacting with a ______ surface
Definition
 smooth
Term
 The type of test object that evaluates sample gate accurancy and registration is the
Definition
 string test object
Term
 The AIUM has issued a statement saying no confirmed biological effects on patients of instruments operators have been reported at intensities below ______ mW/cm squared.
Definition
 100
Term
 Period and frequency are:
Definition
 inversely
Term
 The optimal matching layer thickness is ____ the wavelength
Definition
 1/4
Term
 Axial resolution is determined by:
Definition
 spatial pulse length
Term
 The tyoe of transducer that ulitizies concentric rings is called:
Definition
 annular phased away
Term
 The type of transducer that uses its geometric design to steer the elements and create a quasi sector shape image is called:
Definition
 curved array
Term
 Which of the following is NOT an advantage of harmonic imaging?
Definition
 improved penetration
Term
 Harmonics result from
Definition
 non-linear tissue propagation of sound
Term
 which statement about dicing & sub-dicing of the elements in a transducer is most correct
Definition
 A) provides seperation to eliminate "cross-talk" between elements B) reduces the amount of off-axis energy that causes grating-lobesC) the optimum seperation for most applications is 1/2 the crystal wavelength or lessD) all of these
Term
 An eight bit deep imaging matriz would provide up to _____ shades of gray:
Definition
 256
Term
 What form are the signals as they leave the receiver
Definition
 analog
Term
Definition
 signal integrity
Term
 If the right artial pressure or central venous pressure is increased the veins in the body usually are
Definition
 dilated
Term
 The color priority on color flow instruments is used to:
Definition
 decide the relative contribution of color/echoes on the image
Term
 Color sensitivity is affected by of following factors except:
Definition
 color ROI size
Term
 Refraction causes lateral displacement of the reflector and is caused by _____ incidence
Definition
 oblique
Term
 Section thickness artifacts result from:
Definition
 two adjacent structures visualized as one
Term
 Which one of the following is NOT a function of a test object:
Definition
 beam profile
Term
 The type of test object that contains gel with small spheres in random positions is the
Definition
 PIRTO
Term
 The formula for Positive predictive value (PV+) is:
Definition
 True positives/True positives + false positives
Term
 The beam profile is measured by what method?
Definition
 accoustic optics
Term
 which statement about higher frequencies is most correct?
Definition
 does not affect the propagation speed
Term
 Refraction often causes a type of artifact known as:
Definition
 lateral position error
Term
 In order for a refracted wave to be produced, which of the following conditions must be met at an interface?
Definition
 oblique incidence, different sound speeds
Term
 The resonant frequency of the tranducer is determined by the
Definition
 crystal thickness
Term
 Which is NOT considered a method of focusing
Definition
 geometric design shpe
Term
Definition
 signal integrity
Term
 Advantages of laser imagers above multi-format cameras are all of the following except:
Definition
 inexpensive
Term
 The maximum amount of turbulence is usually detected
Definition
 not in a consistent location
Term
 The color priority on color flow instruments is used to:
Definition
 decide the relative contribution of color/echoes on the image
Term