Healthcare Technology and Function 25% Flashcards
Name a commonly used CO2 absorber?
Soda Lime
What parameter does not affect radiographic contrast?
The level of current used for the exposure
Which of the following is not a factor determining spatial resolution?
-Acquisition
-Frequency (wavelength)
-Transmit intensity
-Pulse interval
Acquisition
By selecting an algorithm, the tech selects:
A mathematical formula for processing data
By selecting an algorithm, the tech selects:
A. The center pixel value in the window width
B. A mathematical formula for processing data
C. The average photon energy of the x-ray beam
D. The shades of gray displayed on the image
B. A mathematical formula for processing data
Another word used to describe a volume element is:
-Voxel
-Particle
-Pixel
-Interpolated plane
-Voxel
Which of the following is affected by the slice spacing in the CT study?
-Radiation dose to the patient
-Signal to noise ratio
-Spatial resolution
-Quantum mottle
-Radiation dose to the patient
Decreasing kV in CT is advantageous because:
-Scan times are reduced
-Tissue contrast improves
-Metal streak artifacts are improved
-X-ray penetration improves
-Tissue contrast improves
Which of the following numbers reported by the CT scanner best reflects the total amount of radiation delivered to the patient?
-Effective mAs
-CT Dose Index (CTDI)
-Dose-length product (DLP)
-Pitch
-Dose-length product (DLP)
CT High-pitch techniques are useful for:
-Very small findings (e.g.
nondisplaced fracture)
-Fast scans
-Gated cardiac CT
-Accurate multiplanar
reconstructions
FAST SCANS
Higher pitch=faster scans
Lower pitch=overlapping scans, extra dose but good for moving parts.
________ is a reconstruction process of spiral/helical CT. It uses a mathematical technique to estimate the unknown value from information on either side.
_Summation
_Convolution
_Interpolation
_Filtering
_Interpolation
The most commonly used reconstruction technique in Cone-Beam CT is called:
-Iterative Reconstruction.
-Filtered Back Projection.
-Fourier Reconstruction.
-Algebraic Reconstruction.
-Filtered Back Projection.
Which of the following is not commonly used as a CT scintillation detector?
-Bisumth germanium oxide
-Silver halide
-Rare earth ceramic
-Cadmium tungstate
-Silver halide
(used on film)
When compared with conventional X-ray, CT produces diagnostic images with improved:
-PT dose
-Minute detail
-Spatial resolution
-Low contrast resolution
-Low contrast resolution
The factors which most greatly affects x-ray quality is:
Time
kVp
mAs
Distance
kVp
Spatial resolution is limited by ______________ .
The digital matrix
kVp
Tube current
Compton scatter
The digital matrix
__________ resolution is a measure of the smallest object that can be resolved by a sensor.
Spatial
Spectral
Temporal
Radiometric
Spatial
What is inverse square law?
Doubling the distance between you and a radiation source, you increase the exposure by one quarter
Doubling the distance between you and a radiation source, you cut the exposure to one quarter
Doubling the distance between you and a radiation source, you increase the exposure by one half
Doubling the distance between you and a radiation source, you cut the exposure by one half
Doubling the distance between you and a radiation source, you cut the exposure to one quarter
Of the listed radiographic densities, in terms of what percentage of the x-rays will be absorbed by each, which is the least radiodense:
Mineral
Water
Fat
Bone
Fat
-least radiodense
All are steps involved in the processing of the film radiograph EXCEPT:
Rinsing
Drying
Printing
Fixing
Printing
One major advantage of real-time radiography over film is:
Higher image definition
Lower equipment costs
Images can be acquired more rapidly
Higher image contrast sensitivity
Images can be acquired more rapidly
In comparison with lower-voltage radiographs, high voltage radiographic images have:
Less latitude
Less contrast sensitivity
Greater scatter amounts of radiation relative to primary beam intensity
Greater contrast sensitivity
Less contrast sensitivity
Radiographic contrast describe:
The average photographic density in a radiograph
The difference in density between two different radiographs
The sharpness of lines in a radiograph
The differences in photographic density in a radiograph
The differences in photographic density in a radiograph
Which of the following does not affect radiographic contrast?
The wavelength of the radiation used
The amount of scattered radiation
The level of current used for the exposure
Attenuation differences in the component being inspected
The level of current used for the exposure
Which of the following is true about grids used in radiographic imaging:
- Use of a grid requires a decrease in exposure technique.
- Use of a grid decreases image contrast.
- A grid reduces scatter radiation received by the x-ray tech.
- Use of a grid requires an increase in exposure technique.
- Use of a grid requires an increase in exposure technique.
Which of the following materials is commonly used as the target in X-ray tubes for the production of X-rays?
a) Copper
b) Aluminum
c) Lead
d) Tungsten
e) Titanium
d) Tungsten
The X-ray tube current (mA) influences which ONE of the following parameters:
Mean energy (quality) of the X-rays
Maximum X-ray energy
Number of X-ray photons
Patient penetration
Number of X-ray photons
The term photon was coined to apply to:
A small wave packet or bundle of electromagnetic radiation.
Any electron emitted from the photo-sensitive surface of an image intensifier tube.
An accelerated electron (in the diagnostic range).
The collimated X-ray beam.
A small wave packet or bundle of electromagnetic radiation.
The proportion of the energy of an electron beam incident on the X-ray tube anode that is converted into X-rays is about:
2.0%.
0.2%.
4.0%.
20%.
0.2%.
As the kV is increased, the contrast between soft and bone tissue seen in a radiographic image:
Increases up to 69.5 kV but then remains constant.
Decreases regardless of the choice of image receptor.
Decreases up to 69.5 kV but thereafter increases due to tungsten K-radiation.
Increases above 80 kVp, especially in Computed Radiography.
Decreases regardless of the choice of image receptor.
The intensity of an X-ray beam increases and the subject contrast remains unchanged by:
Changing from a single phase generator to a three phase one.
Increasing the kVp.
Decreasing the filtration in the beam.
Increasing the exposure (mAs).
Increasing the exposure (mAs).
The inverse square law relationship between radiation intensity and distance from a point source of radiation is due to:
Scatter in air.
Divergence of the X-ray beam.
Absorption in air.
Chance.
Divergence of the X-ray beam.
Increasing filtration reduces the intensity of the X-ray spectrum:
Mostly at the lower photon energies
Equally at all photon energies.
Mostly at the higher photon energies.
Only at the lower photon energies.
Mostly at the lower photon energies
The type of X-ray interaction with matter in which all of the energy of the incident photon is expended in dislodging a bound electron is called:
Photoelectric effect.
Pair.
Compton effect.
None of the above.
Photoelectric effect.
The X-ray tube current is dictated by:
-The filament current.
-The filament current and
the kilovoltage.
-The size of the focal spot.
-The anode speed of
rotation.
The filament current and the kilovoltage.
Electrons striking the tungsten anode of an X-ray tube with 80 keV energy can produce:
-No characteristic X-rays whatsoever.
-Bremsstrahlung X-rays of maximum energy 80 keV.
-Characteristic X-rays of 80 keV.
-Bremsstrahlung X-rays of average energy of 80 keV.
-Bremsstrahlung X-rays of maximum energy 80 keV.
A device used to accelerate charged particles used to produce the isotopes used in PET imaging
A. cyclotron
B. radioactive molecule
C. fluorophores
D. confocal imaging
A. cyclotron
Similar to MRI but is a technique that uses the magnetic properties of cell nuclei to gain information
about the biochemical qualities of the brain
A. MRIs (magnetic resonance imaging)
B. fMRIs (functional magnetic resonance imaging)
C. MRS (magnetic resonance spectroscopy)
D. PET (positron emission tomography) imaging
C. MRS (magnetic resonance spectroscopy)
A device that produces images by reading radioactive substances injected into the body
A. gamma camera
B. confocal imaging
C. digital camera
D. pixel
A. gamma camera
What is the purpose of a grid in radiography?
A To reduce patient exposure
B To improve image contrast
C To enhance spatial resolution
D To increase image brightness
B To improve image contrast
Which of the following is not a component of a radiographic image receptor system?
Collimator
Cassette
Intensifying Screen
Grid
Collimator
Which type of radiation is used in nuclear medicine?
X-Rays
Gamma Rays
Ultraviolet Rays
Infrared Rays
GAMMA RAYS
What is the frequency of a pulse Doppler used for blood flow detection in an ICU?
9.1 MHz
What is the pulse Doppler used for?
To detect blood flow, to locate venous clots near the surface, and to detect blood pressures when a stethoscope cannot be used
True of false Tomo is used for vascular studies?
False, tomo is used for long bones or spines
__________ is a reduction of an image’s brightness or saturation toward the periphery compared to the image center.
-Drop-off
-Halo
-Moiré
-Vignetting
-Vignetting
The indirect Flat Panel Detector uses:
-Zinc cadmium sulfide
-Cesium iodide (CsI) / Amorphous silicon (a-Si)
-Amorphous selenium
-Silicon iodide
Cesium iodide (CsI) / Amorphous silicon (a-Si)
In digital subtraction angiography (DSA), video cameras are generally used in the progressive scan mode. This implies:
-Scanning the video camera target at appropriate intervals during the X-ray exposure
-Scanning adjacent raster lines sequentially after termination of the X-ray exposure
-Repeated scanning of the same video image to improve signal-to-noise ratio
-Use of a double interlaced vidicon beam
Scanning adjacent raster lines sequentially after termination of the X-ray exposure
- (sequential vs interlacing).
A charge-coupled device can be used in digital fluoroscopy:
-In lieu of a conventional video camera to look at the output of the image intensifier
-As a collimation device
-For filtration of the x-ray beam
-As a mechanism to reduce scattered radiation
In lieu of a conventional video camera to look at the output of the image intensifier
Fluorography typically:
-Results in dose rates which are much less than in fluoroscopy
-Refers to a continuous x-ray exposure technique
-Uses dose rates 10-50 times greater than in fluoroscopy
-Produces images of far inferior quality to fluoroscopy
-Uses dose rates 10-50 times greater than in fluoroscopy (uses fluoro to take images)
Pulsed fluoroscopy is generally used to:
-Reduce the effective focal spot size
-Increase kVp stabilization
-Reduce motion blur
-Reduce patient dose
-Reduce patient dose
The magnification mode of an image intensifier is switched from 15 cm to 30 cm. In order to maintain the same image brightness, the exposure at the image intensifier input phosphor must roughly:
-Remain the same
-Double
-Quadruple
-Halve
-Quadruple -(Inverse square law.)
When the magnification mode of an image intensifier is increased, the exposure required by the image intensifier tube also increases. This is because the field of view decreases with increased magnification.
In an X-ray image intensifier, the overall gain in image brightness is of the order 5000:1 but the gain in brightness due to acceleration of electrons is only about 50:1. The other contribution to brightness gain is the:
-Video camera
-Conversion efficiency
-Minification gain due to the reduction of image size
-Preamplifier gain
Minification gain due to the reduction of image size
(Size of II output image vs. size of input image)
Which of the following represents a general size of the output phosphor
*20 – 40 cm
*10 – 20 cm
*2.5 – 5 cm
*100 – 200 cm
-2.5 – 5 cm
Photoemission is a process of:
-Visible light emission following electron stimulation
-Electron emission following light stimulation
-Electron emission following gas stimulation
-X-ray photon emission following electron stimulation
-Electron emission following light stimulation
Which component in an image intensifier is used to minimize S-distortion?
Magnetic shielding
Focusing electrodes
Photo cathode
Output phosphor
Magnetic shielding
Which component in an image intensifier is held at the most negative electric potential?
Focusing electrodes
Output phosphor
Photo cathode
Input phosphor
Photo cathode
Larger patients require higher tube currents (more radiation, increased air kerma) in order to improve image:
Dose
Contrast
Noise
Resolution
Noise (large pts attenuate beam, less electrons at Image receptor)
A _________ cumulative timer is required on all fluoroscopic units to remind the operator audibly of each __________ time interval and to allow the technologist to keep track of the total amount of fluoro time for the exam.
30 minute
20 minute
5 minute
10 minute
5 minute
In a conventional fluoroscopic system images are created and displayed at a rate of:
525 per second
120 per second
1,024 per second
30 per second
30 per second
Visibility of detail in fluoroscopy can generally be improved by using:
Low MA
Low KV
Low exposure rate
Small FOV (field of view)
Small FOV (field of view)
While fluoroscoping, the gain of the image intensifier tube can be increased by increasing the:
KV
Gain control
Density control
Field of view (mode)
Field of view (mode) - Larger field of view increases minification gain.
The fluoroscopic field of view (mode) is increased from 6 in to 9 in. There will be an increase in:
The patient entrance exposure
The gain of the image intensifier tube
The number of video scan lines
The visibility of anatomical detail
The gain of the image intensifier tube
Skin radiation burns are best measured with what metric?
Tube voltage (kV)
Tube current (mA)
Dose-area product (DAP)
Tube air kerma (Ka)
Tube air kerma (Ka)
-Dose time the area is exposed
A 22 cm multi-mode image intensifier is switched to the 11 cm mode. As a result, the image will be _________ and the automatic brightness control system will _________ the exposure to the image intensifier and the patient.
magnified; increase
minified; increase
magnified; decrease
minified; decrease
magnified; increase
Photoemission is a process of:
Visible light emission following electron stimulation
electron emission following light stimulation
electron emission following gas stimulation
X-ray photon emission following electron stimulation
electron emission following light stimulation
-Photoelectric effect: Light Photons incident on material surface causes emission of electrons.
Which of the following represents a general size of the Image Intensifier output phosphor?
20 – 40 cm
10 – 20 cm
2.5 – 5 cm
100 – 200 cm
2.5 – 5 cm
In an X-ray image intensifier, the overall gain in image brightness is of the order 5000:1 but the gain in brightness due to acceleration of electrons is only about 50:1. The other contribution to brightness gain is the:
Video camera
Conversion efficiency
Minification gain due to the reduction of image size
Preamplifier gain
Minification gain due to the reduction of image size
The magnification mode of an image intensifier is switched from 15 cm to 30 cm. In order to maintain the same image brightness, the exposure at the image intensifier input phosphor must roughly:
remain the same
double
Quadruple
halve
Quadruple -(Inverse square law.)
Fluorography typically:
Results in dose rates which are much less than in fluoroscopy
Refers to a continuous x-ray exposure technique
Uses dose rates 10-50 times greater than in fluoroscopy
Produces images of far inferior quality to fluoroscopy
Uses dose rates 10-50 times greater than in fluoroscopy (uses fluoro to take still images)
A charge-coupled device can be used in digital fluoroscopy:
In lieu of a conventional video camera to look at the output of the image intensifier
As a collimation device
For filtration of the x-ray beam
As a mechanism to reduce scattered radiation
In lieu of a conventional video camera to look at the output of the image intensifier
In digital subtraction angiography (DSA), video cameras are generally used in the progressive scan mode. This implies:
-Scanning the video camera target at appropriate intervals during the X-ray exposure
-Scanning adjacent raster lines sequentially after termination of the X-ray exposure
-Repeated scanning of the same video image to improve signal-to-noise ratio
-Use of a double interlaced vidicon beam
Scanning adjacent raster lines sequentially after termination of the X-ray exposure - (technique used for camera: coupled sequential vs interlacing).
_________ is a reduction of an image’s brightness or saturation toward the periphery compared to the image center.
Drop-off
Halo
Moiré
Vignetting
Vignetting
The indirect Flat Panel Detector uses:
Zinc cadmium sulfide
Cesium iodide (CsI) / Amorphous silicon (a-Si)
Amorphous selenium
Silicon iodide
Cesium iodide (CsI) / Amorphous silicon (a-Si)
Pulsed fluoroscopy is generally used to:
reduce the effective focal spot size
increase kVp stabilization
reduce motion blur
reduce patient dose
reduce patient dose
In spin echo sequence TE and TR refer to which of the following, respectively
a. Echo Time, Repetition Time
b. Echo Time, Rephasing Time
c. Elapsed Time, Repetition Time
d. Elapsed Time, rephrasing Time
a. Echo Time, Repetition Time
Computerized Axial Tomography is used to
a. Section tissue along the axis of the nucli
b. Determine movement of the electrical axis of structure
c. Create a picture of tissues in a selected plane of the body
d. Create a picture of a wedge of tissues
c. Create a picture of tissues in a selected plane of the body
Grid Ratio is?
relation of the height of the lead strips to the distance between them
The main clinical role of ultrasound for mammographic procedures is to ?
a. Differentiate cysts from solid masses
b. Reduce patient discomfort from compression
c. Replace routine mammogram screening for asymptomatic patients
d. Increase the need for surgical biopsy on suspicious screen film outcomes
a. Differentiate cysts from solid masses
Which of the following results from a partial transfer of energy from an X-Ray photon to an orbital electron?
a. Compton effect
b. Roentgen effect
c. Thornpson effect
d. Photoelectric effect
a. Compton effect
Primary purpose of an image intensifier?
a. Minification
b. Purification
c. amplification
d. Magnification
c. amplification
An ultrasound piezoelectric transducer converts electrical energy into what type of energy?
a. Radiant
b. Reflection
c. Refraction
d. Mechanical
d. Mechanical
Which of the following is used to assess a radiopharmaceutical just prior to administration to a patient?
a. Spectrophotometer
b. Gamma counter
c. Dose calibrator
d. Pharmaceutical scale
c. Dose calibrator
Used specifically for measuring the activity of radiopharmaceuticals.
What is the typical input dose to a 9” image intensifier in photospot mode?
a. 100 uR per frame
b. 5,000 uR per frame
c. 5 R/minute
d. 10 R/minute
Best Answer:
a. 100 uR per frame
b=too high
c/d=fluoro dose
The purpose of a grid on an x-ray bucky is to:
a. Stop scatter radiation from going to the film or detector
b. Focus the x-ray beam
c. Magnify the x-ray beam
d. Add lines to the film for measurement purposes
a. Stop scatter radiation from going to the film or detector
Ultrasound Energy for imaging is produced by;
a. Piezoelectric Crystal
b. Charging Amp
c. Feedback oscillator
d. Doppler effect
a. Piezoelectric Crystal
Ultrasound is best described as:
a. Radiation
b. Flow of Sonic Particles
c. Electromagnetic Waves
d. Acoustic Compressions
d. Acoustic Compressions
Which technique is commonly used to measure the amount of radiation emitted by radionuclides?
a) Gamma spectrometry
b) X-ray diffraction
c) Mass spectrometry
d) Infrared spectroscopy
a) Gamma spectrometry
What particle does a SPECT camera detect for diagnosis?
A) gamma particles
B) beta particles
C) x-ray photons
D) alpha particles
A) gamma particles
Which is false of single-photon emission computed tomographic (SPECT)?
a. can be used to help diagnose bone disorders
b. allows provider to see how organs are working
c. the scan needs a tracer to be injected
d. the patient will be exposed to no radiation from the tracer
d. the patient will be exposed to no radiation from the tracer
Which of the following is the first object that an emitted gamma photon encounters after exiting the body?
-Collimator
-Photo multiplier tubes
-Position logic circuit
-Detector crystal
-Collimator
Which of the following is known as a scintillation counter?
-Scintillator by itself
-Scintillator along with the crystal
-Scintillator along with a photo
multiplier tube
-Scintillator along with position
circuitry
-Scintillator along with a photo
multiplier tube
Which of the following nuclear medicine instruments forms images resulting from the annihilation of pairs of matter and antimatter particles?
-Scintigraphy scanner
-Positron emission tomography
(PET) scanner
-Single-photon emission
computed tomography (SPECT)
scanner
-Multigated acquisition (MUGA)
scanner
Positron emission tomography
(PET) scanner
Gamma camera uses which of these components to produce a position intensity picture of a radioactive area?
-Photo multiplier tubes
-Position circuitry
-Scintillation detector
-Collimator
-Scintillation detector
Beta decay can be in the form of an electron or a:
Antiproton
Positron
Proton
Neutron
Positron
Which of these particles are highly penetrating?
Alpha particles
Gamma particles
Beta particles
X-ray particles
Gamma particles
Which of the following are highly effective in producing ion pairs when they pass through the matter?
X-ray particles
Alpha particles
Beta particles
Gamma particles
Alpha particles
A __________ is a chemical compound in which one or more atoms have been replaced by a radionuclide, so by virtue of its radioactive decay it can be used to explore the mechanism of chemical reactions by tracing the path that the radioisotope follows from reactants to products.
Isotope
Radio-signal
Radiotracer
Positron
Radiotracer
The radioactive substances used in nuclear medicine are broadly called:
Scintipharmaceuticals
Scintigrams
Radioscintigrams
Radiopharmaceuticals
Radiopharmaceuticals
The first gamma camera is also known by which of the following names?
Anger camera
Hal camera
West cameran
Muller camera
Anger camera
An appropriate kV range for mammography would be:
7kV to 15kV
50kV to 75kV
24kV to 32kV
35kV to 50kV
24kV to 32kV
The photon energy spectrum of the x-ray beam is one of the most critical factors in optimizing a procedure with respect to contrast sensitivity and radiation dose. The spectrum depends on the combination of the following factors EXCEPT:
The anode material
The kV
The exposure time
The selected filter
The exposure time
Mammography requires the use an x-ray beam that has a spectrum that produces an optimum balance between the requirements for __________ contrast sensitivity and __________ radiation dose.
low, high
low, low
high, high
high, low
high, low
HIGH contrast sensitivity and
LOW radiation dose.
If the x-ray spectrum for mammography is decreased below the optimum energy there will be a (an) __________ in the dose because of the __________ penetration through the breast.
decrease, increased
decrease, decreased
increase, decreased
increase, increased
increase, decreased
INCREASE in the dose because of the DECREASED penetration through the breast.
When a(an) __________ filter is used with a molybdenum target, it attenuates and blocks much of the bremsstrahlung spectrum above the energy of 20 keV. This results in the spectrum that is most often used in mammography.
rhodium
aluminum
copper
molybdenum
molybdenum
Mo/Mo combination is most common filter/target combination used in Mammography.
With the __________ filter, the spectrum is shifted to a higher energy (23.22 keV) so that the portion of the bremsstrahlung between 20 keV and 23.22 keV is added to the x-ray beam. This makes the beam more penetrating than when using the other filter and provides some advantage when imaging larger or more dense breast tissue.
aluminum
copper
rhodium
molybdenum
rhodium
-Filter used for dense breasts,
emits higher energy X-ray for better penetration.
Iodine is an effective contrast agent because:
-It has a high mass density
-It has a high likelihood of photoelectric interaction at diagnostic x-ray energies
-It has a high electron density
-It has a high likelihood of Compton interaction at diagnostic x-ray energies
It has a high likelihood of photoelectric interaction at
diagnostic x-ray energies
Molybdenum was traditionally used as an x-ray anode in mammography because of its:
-Intrinsic filtration
-Good heat capacity
-Characteristic x-rays
-Efficient Bremsstrahlung
radiation
Characteristic x-rays
A 22 cm multi-mode image intensifier is switched to the 11 cm mode. As a result, the image will be _________ and the automatic brightness control system will _________ the exposure to the image intensifier and the patient.
magnified; increase
minified; increase
magnified; decrease
minified; decrease
magnified; increase
Skin radiation burns are best measured with what metric?
Tube voltage (kV)
Tube current (mA)
Dose-area product (DAP) Dose
time the area is exposed
Tube air kerma (Ka)
Tube air kerma (Ka)
The fluoroscopic field of view (mode) is increased from 6 in to 9 in. There will be an increase in:
-The patient entrance exposure
-The gain of the image intensifier
tube
-The number of video scan lines
-The visibility of anatomical detail
-The gain of the image intensifier
tube
While fluoroscoping, the gain of the image intensifier tube can be increased by increasing the:
KV
Gain control
Density control
Field of view
Field of view (mode) - Larger field of view increases minification gain.
Visibility of detail in fluoroscopy can generally be improved by using:
Low MA
Low KV
Low exposure rate
Small FOV (field of view)
Small FOV (field of view)
In a conventional fluoroscopic system images are created and displayed at a rate of:
525 per second
120 per second
1,024 per second
30 per second
30 per second
A _________ cumulative timer is required on all fluoroscopic units to remind the operator audibly of each __________ time interval and to allow the technologist to keep track of the total amount of fluoro time for the exam.
30 minute
20 minute
5 minute
10 minute
5 minute
Larger patients require higher tube currents (more radiation, increased air kerma) in order to improve image:
Dose
Contrast
Noise
Resolution
Noise (large pts attenuate beam, less electrons at Image receptor)
Which component in an image intensifier is held at the most negative electric potential?
Focusing electrodes
Output phosphor
Photo cathode
Input phosphor
Photo cathode
Which component in an image intensifier is used to minimize S-distortion?
Magnetic shielding
Focusing electrodes
Photo cathode
Output phosphor
Magnetic shielding
Ultrasound energy, simply known as ultrasound, is a type of __________ energy.
Chemical
Light
Mechanical
Electromagnetic
Mechanical
An ultrasound beam is attenuated:
By scattering
By absorption in tissues
By reflection at a tissue interface
All are true
All are true
The Doppler effect is a change in echo ______.
Frequency
Direction
Strength
Amplitude
Frequency
The propagation speed of sound through soft tissue is:
1650 m/s
1230 m/s
1450 m/s
1540 m/s
1540 m/s
*most likely on CRES
Attenuation increases as frequency ______.
Increases
Decreases
Increases
Attenuation increases as distance _____.
Decreases
Increases
Increases
The following are all ultrasound frequencies except:
250 KHz
30,000 Hz
15 KHz
0.3 MHz
15 KHz
Which of the following types of tissue would have the lowest mean propagation velocity.
Fat
Blood
Water
Air
Air
A piezoelectric crystal may be made of:
aluminum
calcium tungstate
quartz
lithium fluoride
quartz
By definition, ultrasound is sound having a frequency greater than __________ cycles per second, that is, sound above the audible range.
40,000
20,000
30,000
10,000
20,000 cycles
20Khz
The basic unit used to describe the energy of a radiation particle is the __________ .
Sievert (Sv)
Electron volt (eV)
Curie (Ci)
Becquerel (Bq)
Electron volt (eV)
__________ places an X-ray source and an x-ray detector array between the gamma camera heads.
SPECT
Bone Scan
Hybrid SPECT/CT
PET scan
Hybrid SPECT/CT
Which of the following variables does not affect spatial resolution in nuclear medicine imaging systems?
Energy of the gamma rays being counted
Byte vs. word acquisition mode
Computer matrix pixel size
Material of which the collimator is constructed
Byte vs. word acquisition mode
Scintillation detector is a large flat crystal of which of the following materials?
Sodium carbonate
Sodium iodide
Sodium chloride
Sodium sulphate
Sodium iodide
__________ collimator is used for thyroid work in the medical field.
Fanbeam
Straight bore
Pinhole
Low Energy All-Purpose (LEAP)
Pinhole
__________ imaging measures the gamma events created by the collision between an electron and a positron.
PET
Hybrid SPECT/CT
Gamma camera
SPECT
PET
Which of the following components adds all the signals and determines where each scintillation event occurred in the detector?
Photo multiplier tubes
Position circuitry
Collimator
Detector crystal
Position circuitry
When the energy of an absorbed gamma photon is released, a flash of light is produced. This is similar to which of the following effects?
Compton effect
Photoelectric effect
Collision effect
Pair production
Photoelectric effect
Which of the following is a pattern of holes through gamma ray absorbing material, usually lead or tungsten?
Collimator
Photo multiplier tubes
Position circuitry
Detector crystal
Collimator
The axial resolution of a US transducer is primarily determined by:
The transducer diameter
Spatial pulse length
Density
The acoustic impedance of tissue
Spatial pulse length
US Lateral resolution can be improved by:
Damping
Pulsing
Reflecting
Focusing
Focusing
Which of the following is not a factor determining US spatial resolution?
Transmit intensity
Pulse interval
Frequency (wavelength)
Acquisition
Acquisition
______ is defined by the number of elements used (effective transducer width).
Aperture
Transducer
Linear
Propagation
Aperture
US Axial resolution can be improved by:
Focusing
Increasing operating frequency
Pulsing
Damping
Increasing operating frequency
The lateral resolution of a transducer is primarily determined by:
Applied voltage
The beam width
Spatial pulse length
The acoustic impedance of tissue
The beam width
In an ultrasound transducer, the __________ stops vibrations reverberating back into the piezoelectric material, and determines the length of the ultrasound pulse by determining how much it is damped.
Acoustic insulator: stops the transducer vibrating in hand.
Matching layer
Backing material
Exterior plastic casing
Backing material
The main mode used in diagnostic ultrasound is:
A-mode
Doppler
B-mode
M-mode
B-mode
The most common design configuration for clinical MR scanners is:
Open bore superconducting
Dipolar electromagnet
Open bore permanent
Closed bore superconducting
Closed bore superconducting
The highest field strength permitted for adults in routine clinical practice by the United States Food and Drug Administration (FDA) is:
8.0 Tesla
3.0 Tesla
11.7 Tesla
7.0 Tesla
8.0 Tesla
The direction of the main magnetic field (Bo) in a cylindrical closed bore scanner is:
-Can be at any angle depending on which gradients are turned on
-Vertical (cross-wise to the cylinder and perpendicular to the floor)
-Longitudinal (along the main axis) of the cylinder
-Horizontal (cross-wise to the cylinder and parallel to the floor)
Longitudinal (along the main axis) of the cylinder
Which of the following is not an advantage of high-field (≥ 1.0 T) MR scanners?
-Better detection of calcifications and hemorrhage
-Smaller artifacts around metallic implants
-Better magnetic field homogeneity
-Higher signal-to-noise
-Smaller artifacts around metallic implants
Which scanner would have the largest fringe field?
0.6 T Resistive magnet system
3.0 T Superconductive system
1.5 T Superconductive system
0.35 T Permanent magnet system
3.0 T Superconductive system
The cryostat of a typical superconducting MR scanner contains all of the following except:
-Main magnet windings
-Liquid nitrogen
-Superconducting shim coils
-Liquid helium
Liquid nitrogen
The temperature of liquid helium is approximately:
a) 0 °K
b) −4 °K
c) 4 °K
d) −400 °C
c) 4 °Kelvin
4.2Kelvin more precise or -296 degrees Celsius or -452 Fahrenheit
How many sets of paired physical gradients are present in an MR scanner?
6
1
2
3
3
Passive magnetic shielding of the scanner room is typically achieved using sheets or rods made of:
Iron
Aluminum
Copper
Lead
Iron
Which of the following statements about the gradient subsystem is true?
-The gradient coils are cooled by liquid helium.
-The gradient coils are located within the cryostat.
-Increasing power supplied to a gradient decreases the slope of the gradient.
-Gradient coils generate considerable heat during operation.
-Gradient coils generate considerable heat during operation.
The most common metal used for RF shielding is:
Nickel
Lead
Aluminum
Copper
Copper
Where is the master computer located that controls the MR scanner and processes data into images?
At least 25 meters distant from the main scanner to avoid interference
In the MR scanner control room
In the MR scanner room
In the nearby MR equipment room
In the MR scanner control room
In the construction of a superconducting MR magnet, which is the correct order of coils from outermost to innermost?
-RF coils, shield coils, main magnet windings, gradient coils
-Gradient coils, shield coils, main magnet windings, RF coils
-Main magnet windings, gradient coils, RF coils, shielding coils
-Shielding coils, main magnet windings, gradient coils, RF coils
-Shielding coils, main magnet windings, gradient coils, RF coils
The time for a gradient to ramp from zero to its maximum value is known as its:
-Rise time
-Duty cycle
-Gradient time
-Slew rate
-Rise time
Whereas most x-ray tubes use tungsten as the anode material, mammography equipment uses __________ anodes.
aluminum
copper
molybdenum
rhodium
-molybdenum
In order to distinguish cancer from glandular tissue, mammography relies on:
-Low x-ray energies to increase photoelectric effect
-High tube currents (mA)
-Low x-ray energies to increase Compton scattering
-Intravenous contrast agents
-High x-ray energies to increase photoelectric effect
-Low x-ray energies to increase photoelectric effect
Tissue contrast is generated by what type of interaction?
-Beam hardening effect
-Overall attenuation
-Incoherent (Compton) scatter
-Photoelectric effect
-Coherent (Rayleigh) scatter
-Photoelectric effect
The typical x-ray tube for mammography has two selectable focal spots. The spots are generally __________ than for other x-ray procedures because of the requirements for minimal blurring and good visibility of detail to see the small calcifications.
-larger
-deeper
-smaller
-wider
-smaller
Whereas most x-ray tubes use tungsten as the anode material, mammography equipment uses __________ anodes.
-aluminum
-copper
-molybdenum
-rhodium
-molybdenum
The process of destroying cancer cells with the help of radiation is known as:
uroplasty
physiotherapy
rehabilitation
radiotherapy
radiotherapy
Which of the following pair of scattering is important for therapeutic purposes?
Coherent and Pair Production
Compton and Photoelectric
Photoelectric and Disintegration
Pair Production and Disintegration
Pair Production and Disintegration
The direction of the main magnetic field (Bo) in a cylindrical closed bore scanner is:
-Longitudinal (along the main axis) of the cylinder
-Vertical (cross-wise to the cylinder and perpendicular to the floor)
-Horizontal (cross-wise to the cylinder and parallel to the floor)
-Can be at any angle depending on which gradients are turned on
-Longitudinal (along the main axis) of the cylinder
The temperature of liquid helium is approximately:
−4 °K
−400 °C
4 °K
0 °K
4 °K
Magnetic field gradients for imaging are typically measured in units of:
Gauss per second (G/s)
Tesla (T)
Tesla per meter per second (T/m-s)
Millitesla per meter (mT/m)
Millitesla per meter (mT/m)
High-pitch techniques are useful for:
Fast scans
Very small findings (e.g. nondisplaced fracture)
Gated cardiac CT
Accurate multiplanar reconstructions
Fast scans
In helical CT, pitch is defined as:
Patient dose in 360 degrees / beam width
Reconstructed slice thickness / beam width
Table movement in 360 degrees / beam width
Gantry angle with respect to the scan axis
Table movement in 360 degrees / beam width
In helical CT, a single transverse slice represents:
A plane through the body perpendicular to the scan axis
A plane through the body oblique to the scan axis
A reconstruction made from projections averaging the entire scan
A reconstruction made from projections at neighboring scan axis positions
A reconstruction made from projections at neighboring scan axis positions
The ‘filter’ in filtered backprojection refers to:
-Altering the projection data before performing the back-projections
-Conversion between fan-beam and parallel geometry
-Conversion between attenuation and Hounsfield units
-Bowtie filter between the beam and patient
-Altering the projection data before performing the back-projections
The CT number (Hounsfield unit) of fat depends on:?
mAs
Reconstruction algorithm
kV
Nothing - it is constant
kV
The time for a gradient to ramp from zero to its maximum value is known as its?
Duty cycle
Gradient time
Rise time
Slew rate
Rise time
18.Which of the following statements about the gradient subsystem is true?
-The gradient coils are located within the cryostat.
-Increasing power supplied to a gradient decreases the slope of the gradient.
-The gradient coils are cooled by liquid helium.
-Gradient coils generate considerable heat during operation.
-Gradient coils generate considerable heat during operation.
Which component of a superconducting MR scanner does not require specialized cooling to maintain function?
Gradient amplifiers
Gradient coils
Main coil windings
Radiofrequency coils
Radiofrequency coils
In the construction of a superconducting MR magnet, which is the correct order of coils from outermost to innermost?
Gradient coils, shield coils, main magnet windings, RF coils
Main magnet windings, gradient coils, RF coils, shielding coils
Shielding coils, main magnet windings, gradient coils, RF coils
RF coils, shield coils, main magnet windings, gradient coils
Shielding coils, main magnet windings, gradient coils, RF coils
The basic coil configuration used to generate the z-gradient in a cylindrical MR scanner is known as?
Fingerprint
Golay
Maxwell pair
Double saddle
Maxwell pair
Magnetic field gradients for imaging are typically measured in units of:
Tesla per meter per second (T/m-s)
Millitesla per meter (mT/m):
Gauss per second (G/s)
Tesla (T)
Millitesla per meter (mT/m):
