Red physics edlemen book ardms/spi
Refraction
Snells law describes ?
False
Sonographer education ends when they become registered ?
6dB
Sound intensity is decreased your 75%. How many decibels of attenuation is this?
angle of incidence=angle of reflection
Sound traveling from medium 1 to medium 2. Propagation speeds of M1 and M2 are 1,600 m/s and 1,500 m/s,respectively. There is a normal incidence.
Longitudinal,mechanical
Sound waves are ?
Reflection increases
As The impedance of two media become vastly different, the
Decreasing compressibility and decreasing density
As a result of ___________ the propagation speed increases.
The beam width is near field is increased
Assuming a constant frequency, what happens if the diameter of an unfocused circular transducer is increased?
Half
At the focus, the beam diameter is ____ the transducer diameter.
0.6dB/cm/MHz
Attenuation of US is soft tissue is closest to ?
Frequency,MHz
For soft tissues, the approximate attenuation coefficient in dB/cm is equal to one half ______ in ________.
Low transmit output and high receiver gain
From a safety standpoint,which one of the following methods is best ?
Depth decreases
If the frame rate increases and lines per frame is unchanged,what else must happen ?
Increased
If the frequency is decreased,the numerical value of the radial resolution is ?
Doubles
If the intensity is increased by 3dB,it:?
Halved
If the intensity of a sound beam remains unchanged whiles the beam area is reduced in half,what has happened to the power?
0.5cm
If the spatial pulse length is 10mm,what is the axial resolution ?
Frame rate increases
If the the lines per frame is increased while the imaging depths is unchanged then ?
Increase.
If the transducer aperture increases, the lateral resolution at its smallest dimension is ?
Increased
If we increase the frequency the near zone length is ?
Decreased
If we increase the transducer diameter,the beam diameter in the far zone is ?
Magnetism
Image on videotape are stored using ?
Product,propagation speed,density
Impedance is the _____ of _______ and ______.
Density and propagation speed
Impedance is the product of _________ and __________.
Near 100%
In an air-tissue interface,what percentage of the US is reflected?
Depth of view
In real time scanners,which of these choices determines the maximum frame rate?
Propagation speed
In soft tissue: distance traveled =_______x round trip time.
Tendon
In which of these biologic tissues will sound waves propagate most quickly ? Tendon,blood,lung,fat,amniotic fluid
Lower PRF
How is range ambiguity artifact eliminated ?
10
How many bits are needed to represents 1024 gray shades ?
4
How many bits are needed to represents 16 shades of grey?
6
How many cm are 60 millimeters?
6
How many data bits are needed to represent 46 gray shades?
Penetration
Identify one of the advantages of coded excitation. ?
Improved contrast resolution
Identify one of the advantages of coded excitation?
Speed of sound in bind is the highest.
If a 5MHz sound wave is traveling in the tissues listed below which will have the shortest wavelength ? Fat,air,muscle,bone
air
If a 5MHz sound wave is traveling in the tissues listed below,which will have the shortest wavelength?
Frame rate
If a manufacturer changed the line per frame and kept the imaging depth the same, what else would change ?
Double it
If a reflector is moved twice as far away from the transducer,how will this affect the time - off -flight of a sound pulse ?
Quadrupled
If a waves amplitude is doubled, what happens to the power?
The annular Array is steered mechanically
In which way is an annular phase Array transducer different than a linear phased Array transducer?
Amplitude
The dynamic range is the ratio of the smallest the largest _______ that a system can process without distortion.
Acoustic propagation properties
The effects of soft tissues on US are called?
15,000 Hz
The frequency closest to the lower limit of US is?
5MHz
The fundamental frequency of a transducer is 2.5MHz. What is the second harmonic frequency?
Halved
Traveling through the same medium, if the frequency is doubled, the wavelength is ?
Unchanged
Traveling through the same medium, if the frequency is doubled,the propagation speed is ?
90 degrees
For Doppler,which incident angle results in no shifts ?
At any time
When can a patient revoke consent?
By the manufacture
A single element transducer is focused ?
False
(True or false ) the digital scan converter has a number of pixels assigned to each bit.
True
(True or false) Doppler shifts always occur if the source and observer are in motion relative to each other and the angle between the motion and the sound beam is not 90 degrees.
False
(True or false) Doppler shifts always occur if the source and receiver are in motion relative to each other?
False
(True or false) The Doppler shifts always occur if the second source and receiver are in motion.
True
(True or false) a sound wave is a pressure wave made of compression and rarefactions.
True
(True or false) a system which was display clear images in the far field. This may be a problem with the ?
False
(True or false) increasing the frequency increases the penetration depth ?
Azimuthal
(True or false) lateral resolution is also called ?
True
(True or false) shadowing may result from high amounts of reflection of US energy.
False
(True or false) there have not been biological effects from US found in the laboratory.
False
(True or false) with normal incidence the angle is 180 degrees.
False
(True or false)Doppler shifts always occur if the source and observer are in motion relative to each other and the angle between the motion and the sound beam is 90 degrees
False
(True or false)The sonographer cannot change directly or indirectly, the duty factor of an US machine.
False
(Trueorfalse) axial resolution if affected by focusing.
True
( true/false) gray scale can be changed by the sonographer.
False
( true/false) with right angle incidence, reflections are always generated at a boundary if the propagation speeds of the media are different.
False
(T/f) a mirror image Artifact can appear along side of the true anatomy
True
(True /false) the manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased. Frame rate,sector angle,image depth
False
(True /false) the manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased. Frequency and power output?
False
(True or false ) sonographers cannot affect a patients exposure to acoustic energy.
10^-6
-micro
-milli
10-3
Kilo
10^3
Mega
10^6
0.3MHz
3000,000 cycles occurs in a second, what is the waves frequency?
14 kHz
A Doppler exam is performed with a 5kHz probe and PRF of 15 kHz.which of these Doppler shifts will create aliasing ?
Frequency and intensity
A hydrophone is used to measure ?
10 cm
A pulse is emitted by a transducer and is traveling in soft tissue. The go return time, or time of flight,of a sound pulse is 130 microseconds. What is the reflector depth ?
Needed by all labs
A quality assurance program :?
Converts,energy
A transducer ______ one form of ____ into another.
Array
A transducer with more the one active element is called ?
0.1
According to the aium statement on bio effects, there statements on bio effects, there have been no confirmed bio effects below intensities of_______ watts per square centimeter SPTA.
Harmful bio effects are are commonly observed
All of the following are true of normal cavitation EXCEPT ? Known as internal cavitation, only 10%increases in pressure is needed to convert to this from stable cavitation,temp in the thousands of degrees are created.
In vitro bioeffects conclusion are clinically relevant
All of the following statements regarding in-vitro bioeffects are true except.
Increased line density
All of the following will improve temporal resolution except ?
8dB
An US wave travels through two media and has attenuation of 3dB in the first and 5dB in the second. What is the total attenuation ?
3cm
An object is located at a depth of 10 cm. The imaging depth is 7cm. At what depth will a reflection from the object appear on the image ?
-10dB
An ultrasound system is set at 0dB and is transmitting at full intensity. What is the output power when the system is transmitting at 10% of full intensity?
100 mW/cm2
Biological effects have not been documented below what intensity (SPTA)?
Display brightness &contrast
Changing which of the following would not cause any change in a hard copy image output ? I'm
Cm
Circumstances may be measured in units of ?
Decrease the range of amplitude
Compression is used to ?
45mm
Depth calibration of a machine measures 100mm spaced wires to be 90mm apart.scanning reflectors 50mm apart. Scanning reflectors 50mm apart,what will the machine calculate the distance to be ?
Artifact
Enchantment,multipath and side lobes result in?
Artifact
Enhancement, multipath and side lobes results in ?
(True/false) Doppler shifts are always created when the source and receiver are in motion relative to each other.
False
Ghosting artifact
Fill-in of an anechoic structure such as a cyst is known as all of the following. Except ? Partial volume artifact, slice thickness artifact, section thickness artifact,Ghosting artifact
Focusing
Lateral resolution can be improved by ?
Reverberations
Multiple reflections that are equally spaced are called ?
Entered the A/D convert but before display
Post processing occurs
Watts
Power of sound has units of ?
When the patient is being scanned
Pre-processing occurs ?
frquency
Propagation speed = ________ x wavelength
Solid, liquid,gas
Put in decreasing order of propagation speed. Gas, liquid,solid
Air water bone
Put in decreasing order of propagation speed? Air,water,bone
Deca,deci,micro,centi
Put in decreasing order.? Deca,Deci,micro,centi
Demodulation
Rectification and smoothing are components of which of the following ?
Oblique incidence & different propagation speeds
Refraction only occurs if there are ?
Alter the appearance of lowly reflective objects
Reject is used ?
Alter the appearance of lowly reflective objects
Reject is used to?
Difference between incident & reflected frequency
The Doppler shift is a measure of :
Difference
The Doppler shift is the _________ of two frequencies
Near zone
The Fresnel is the ?
Analog to digital converter
The US machine has a digital scan converter but has an analog input signal. The machine needs to have a ?
Orthogonal incidence
The angle between an US pulse and the boundary between two media is 90 degrees. What is this called?
oblique incidence
The angle between an US pulses d boundary between two media is 56 degrees. This is called
Persistence
The consolidation of many images into a single frame best describes which of the following ?
Spatial compounding
The creation of an image by scanning from different angles best describes ?
The ferroelectric material is depolarized
The curie temperature has which effect ?
Ratio
The dB is defined as the _______ of two intensities.
2times
The distance to a target is doubled. The time-of-flight for a pulse to travel to the target and back is ?
1.0
The duty factor for continuous wave ultrasound is ?
Stable cavitation
The interaction of microscopic bubbles and ultrasound form the basis for cavitation bio effects. which of the following forms of cavitation are most likely to produce micro streaming in the intracellular fluid and shear stresses ?
The more shades of gray
The more bits per pixel ?
The better is the spatial resolution
The more pixels per inch?
1%
The most likely amount of reflection at a boundary between soft tissue is ?
99%
The most typical amount of transmission at a boundary in biologic media is ?
Compression
The process of reducing the difference Between the smallest and largest voltage is called ?
1.54 m/s
The propagation speed of US in the AIUM test objects is ?
Time of flight,propagation speed
The range equation relates distance from the reflector to ____ and_____.
Impedance
The rayl is the unit ?
Fresnel zone
The region from the transducer to the minimum beam cross-sectional area is the ?
One million times
The relative output of an US instrument is calibrated in dB and the operator increases the output by 60 dB. The beam intensity is increased by which of the following ?
1,500 m/s
The speed of US in soft tissues is closest to ?
Pulse duration
The time from the beginning of a pulse until it's end is ?
dB,logarithmic
The unit of attenuation are ____, this is a _____scale?
Per min
The units of pulse repetition frequency are ?
Calibrated hydrophone
To measure the US beam intensity, use a.?
(True or false) gray scale can be changed by the sonographer.
True or false) gray scale can be changed by the sonographer.
Pay your dues
Ultrasound physics is nothing to fear and can almost be fun if you remember to ?
Low frequency and high signal amplitude
Under which circumstances is cavitation most likely to occur ?
High frequency and low power
Under which circumstances is the mechanical index lowest ?
Decreased spatial pulse length
Under which of the following conditions is axial resolution improved ?
Decrease beam diameter
Under which of the following conditions is lateral resolution improved ?
Cm3
Volume has which of the following units ?
60-75 degrees
What Doppler angle is most inaccurate?
Scattering,reflection,absorption
What are attenuations three components?
Watts are the units of intensity
What are the units of intensity?
watts/cm squared
What are the units of intensity?
Feet
What are the units of longitude resolution?
1-10MHz
What are typical clinical Doppler frequencies?
Speckle
What artifact had a grainy appearance and is caused by the interference effects of scattered sound?
What artifact has a grainy appearance and is caused by the interference effects of scattered sound?
What artifact has a grainy appearance and is caused by the interference effects of scattered sound?
Range ambiguity
What artifact is created by an object that is located deeper than the image ?
Location
What can Pulsed Doppler measure that continuous wave cannot?
PZT
What component of a transducer changes electrical to mechanical and mechanical back to electrical energy ?
Scan converter
What components of the US unit contains the memory bank ?
PZT thickness
What determines the frequency of a sound beam from a pulsed transducer ?
Faster
What happens to the speed of sound in a medium when the when the bulk modulus of the medium increases?
Slower
What happens to the speed sound in a medium when the bulk modulus of the medium when the bulk modulus of the medium decreases ?
Decrease
What happens to venous return to the heart during expiration?
Exam time
What increases patient exposure ?
Velocity
What information does Doppler shift provide ?
Depth and lateral
What is another names for longitudinal resolution ?
Adjust converts matrix
What is not the responsibility of the sonographer?
density and elasticity
What is propagation speed determined by ?
Pulse duration
What is the actual time that an US machine is creating a pulse ?
0.5dB/cm
What is the approximate attenuation coefficient of 1 MHz US in soft tissue ?
dB
What is the correct unit for attenuation?
W/cm2
What is the correct unit for intens ?
M/sec
What is the correct unit for speed?
MHz
What is the correct units for freq?
Reject
What is the elimination of voltages that do not exceed a certain level?
Duty factor
What is the fraction of time that a transducer is transmitting ?
Far zone
What is the franunhofer?
1kHz
What is the frequency of a wave with 1 msec period?
Focus
What is the location of the minimum cross-sectional area of the US beam called?
0.0%
What is the maximum value of the duty factor ?
Tissue temperature may rise 3 degrees Celsius
What is the meaning of a thermal index = 3?
2kHz
What is the most typical Doppler shift measured clinically?
Compensation
What is the name of the receiver function that corrects for attenuation ?
Piezoelectricity
What is the production of deformation from voltages called ?
2-10MHz
What is the range of frequencies created by medical diagnostics Doppler transducer ?
It represents the number of red blood cells creating the reflection
What is the significance of gray scale variation in the spectrum of a pulsed wave Doppler display ?
DICOM
What is the standard for communication between medical imaging computers ?
Cm
What may be a unit of amplitude ?
Hydrophone
What measures the output power of a transducer ?
Increase output power
When the US machine displays only strong reflections objects and nothing else,the sonographer should ?
Cosine
When the sound source and the receiver are not moving directly towards or away from each other, the _______of the angle between them enters into the calculations of Doppler shift.
In the tissues
Where are harmonics created ?
In the pulser
Where does coded excitation originate ?
The pulser
Where does coded excitation originate ?
Poor temporal resolution and flash artifact
Which I found the following is associated with power mode Doppler ?
Bone
Which has the greatest amount of attenuation?
Intensity
Which is not an acoustic variable ?
Intensity
Which is not an acoustic variable?
Phased beam
Which of following is not a beam steering technique for a mechanical scan head?
30 KHz
Which of following sound waves is ultrasonic and least useful in diagnostic imaging?
3-D rendering
Which of the following Is not preprocessing?
A collection of mechanical vibrations in the form of compression and rarefractions
Which of the following best describes a sound beam ?
Exposure -response
Which of the following best describes the empirical approach to the study of the bio effects?
Density of the medium and stiffness of the medium
Which of the following best describes the features of a sound wave and medium that determines the speed of sound in the medium ?
Cause - effect
Which of the following best describes the mechanistic approach to the study of bio effects ?
Randomized and prospective
Which of the following choices best describe an ideal epidemologic bioeffects study ?
Reflected intensity of the sound beam
Which of the following choices determines the signal amplitude in the transducer of the ultrasound system?
Gray scale imaging
Which of the following clinical modalities has the lowest output power .pulsed Doppler,power Doppler,duplex scanning,continue wave
Spatial resolution
Which of the following does not change temporal resolution?
Muscle
Which of the following has a propagation speed closest to soft tissues ?
Propagation speed and imaging depth
Which of the following has the greatest influence on temporal resolution ?
Propagation speed and the imaging depth
Which of the following has the greatest influence on temporal resolution?
Pulsed Doppler
Which of the following has the greatest output intensity?
Frame rate average
Which of the following improves the signal to noise ratio ?
Mechanical index
Which of the following is associated with cavitation ?
Mechanical index
Which of the following is associated with cavitation?
Range resolution
Which of the following is determined by the source and the medium ?
Power
Which of the following is proportional to the square of amplitude ?
0.06cm
Which of the following is the best lateral resolution?
coded excitation
Which of the following will eliminate range ambiguity artifact ?
Imaging deeper
Which of the following will eliminate range ambiguity artifact?
Lowering the PRF
Which of the following will eliminate range ambiguity artifact?
Large pixels with many bits/pixels
Which of the following will result in the greatest number of shades of gray in a digital image display ?
lower frequency and high signal amplitude
Which of the following will result in the highest mechanical index ?
Red blood cells
Which of the tissues is most likely to create Rayleigh scattering ?
Air-soft tissue
Which of these boundaries will create the strongest reflection?
Soft tissue- blood
Which of these boundaries will create the weakest reflection ?
Clean pixels
Which of these cannot be performed by a sonographer ?
Display
Which of these factors had the greatest influence on pulse repetition prriod?
SATA
Which of these intensities is the smallest ?
Reflector spacing and propagation speed
Which one of the following sets of properties of a test phantom is most relevant when assessing depth calibration accuracy?
A/D wire
Which part is not part of a transducer?
Large diameter,high frequency
Which transducer would be best to to image superficial structures?
Shadowing
Which type of artifact appears most commonly with highly reflected objects ?
Traveling in a straight line, reflected & retuned.
While propagation, a sound wave Is refracted. Finally, it returns to the transducer. The system processes the sound wave as if it has ?
Focal point
While scanning in a water tank,what location in a sound beam has the highest intensity?
Adjust the recorder
With good images on the display but not on the printer one should ?
None of these
With normal incidence,what factors affect refraction of US? Propagation speeds, frequencies,attenuation coefficient
Reverberations
With the presence of _______ we see more boundaries than there are reflecting surfaces.
System sensitivity
You are performing a quality assurance study on an ultrasound system using a tissue equivalent phantom . You make an adjustment using a knob on the system console that changes the appearance of reflector brightness from fully bright to barely visible. What are you evaluating ?
Call for hospital interpreter
You encounter a patient that does not speak English. Which of the following is best to obtain informed consent ?
Politely check the patients wristband for identification
You enter a hospital room to perform an ultrasound exam.which of the following should you do first?
Period
_______ in the time to complete one cycle?
Scattering
_________ is a redirection of US in many directions as a result of a rough boundary between two media.
Radial and axial
_________ resolution is determined by the spatial pulse length.
-3 dB
an ultrasound system is set At 0dB and is transmitting at full intensity. What is the output power when the system is transmitting at 50% of full intensity?
Piezoelectricity
the production of a voltage from the application of a pressure is called ?