Healthcare Technology Problem Solving 25% Flashcards
A radiologist wants to improve the spatial resolution of the anatomy being examined. The change most likely to lead to this is:
-decreased collimation.
-increased matrix size, same field of view.
-selection of a smoothing algorithm.
-increased field of view, same matrix size.
-increased matrix size, same field of view.
Which of the following has the highest patient dose assuming all other parameters are the same?
-mA =150, rotation time = 3 seconds
-mA =200, rotation time = 2 seconds
-mA =200, rotation time =1 second
-mA =400, rotation time =1 second
-mA =150, rotation time = 3 seconds
(highest mAs)
The mathematical technique that involves the estimation of an unknown value from values on either side of it is known as:
-Interpolation
-Filtering
-Convolution
-Summation
Interpolation
The slip ring on continuous rotation CT scanners:
1. prevents the high voltage cable from winding up
2. allows the exam to commence more rapidly
3. eliminates the need for the reversal of gantry frame rotation
1 and 2 only
1 and 3 only
1, 2, and 3
3 only
1, 2, and 3
The major technical challenge in cardiac CT is:
-Three-dimensional reconstruction
-Temporal resolution
-Contrast resolution
-Spatial resolution
-Temporal resolution
(Resolution of moving parts)
Which of the following reconstruction methods is used by most modern CT scanners?
-Back projection
-Filtered back projection
-Iterative method
-Fourier transform
-Filtered back projection
An accurate, modern CT scanner is capable of spatial resolution of up to _________:
20 lp/mm
100 lp/cm
10 lp/mm
20 lp/cm
20 lp/cm
Pixels representing tissues with average attenuation coefficients greater than that of water have which of the types of values?
-Negative
-None are correct
-Positive
-Extremely small
Positive
During a CT examination, the mA setting determines the:
-quantity of x-ray photons
-energy level of the x-ray photons
-slice thickness
-coefficient of attenuation
-quantity of x-ray photons
What indicates a light leak on a film after developing?
Fog along the developed film edge
Compton scatter is similar to characteristic radiation, True or False.
TRUE
The filament voltage in an x-ray tube are measured in mA, True or False?
False, mA is a current measurement
Focal spots remain constant over the life of the tube,
True or False?
False, it increases in size with age
99% of the energy created by an x-ray tube is heat, True or False?
True, even after 107 plus years of development
What are the 4 items recorded on the QA program of a film processor?
Base fog, speed, contrast, (sometimes called density readings), and temperature.
A high frequency power supply provides less consistent x-ray output then a 12 pulse power supply system,
True or False?
False, a high frequency power supply provides the most consistent output
If fog is increased on a diagnostic image, which of the following occurs
a. Contrast decreases
b. Contrast increases
c. Density decreases
d. Contrast is unchanged
a. Contrast decreases
A major problem w/over processing is that it increases
fog which contributes to decrease in contrast.
A cracked anode is most likely caused by
a. Using the unit at high KVp and low mA
b. Using the unit at low KVP and low mA for 2 seconds
c. Making a high kVp exposure with a cold tubes
d. Making a 100mA -110kVp, 0.5 sec exposure on tube
c. Making a high kVp exposure with a cold tubes
Which of the following is a common treatment for breast cancer
a. Mammogram
b. Bone Densitometry
c. Oncology Simulation
d. Intensity Modulated radiation therapy
d. Intensity Modulated radiation therapy
IMRT has been used in limited situations to treat breast cancer.
Spatial resolution is measured in
a. Parallel white lines
b. Parallel Black lines
c. Line pairs per millimeter
d. Contrast to sharpness ratio
c. Line pairs per millimeter
A radiographic technique calls for a 90 kVp , 80mA, 200mS, and a SID of 100cm. What is the mAs?
a. 4
b. 16
c. 40
d. 160
b. 16 mAs
.08 x .2 =.016
With technique factors constant, as the SID is increased, film density will
a. Increase
b. Decrease
c. Double
d. Remain the same
b. Decrease
Inverse square law
Radiology technician reports the X-Ray table does not tilt, which of the following should be checked first?
a. Tilt motor
b. Table leveling
c. Safety interlocks
d. Technique settings
c. Safety interlocks
Changing the grid ratio from 5:1 to 12:1 requires which of the following to maintain the same density?
a. Lowering kVp
b. Raising mAs
c. Lowering mAs
d. No exposure changes
b. Raising mAs
Amount of radiation delivered to the patient’s body must be increased to compensate for the radiation absorbed by the grid.
Which of the following is most likely to cause an underexposed X-Ray film
a. KVP too high
b. mA too low
c. Exposure time too long
d. Source to image distance too short
b. mA too low
– too little mA = underexposure
Barium as a radiographic contrast medium is
a. Radiolucent
b. Radiopaque
c. radioactive
d. radio luminescent
b. Radiopaque
-absorbes x-rays
In third generation CT scanners, if detectors are faulty or mis-calibrated, what artifact may appear
a. Ring
b. Motion
c. compression
d. Beam-hardening
a. Ring
Which of the following best describes digital image enhancement?
a. Smoothing and edge enhancement only
b. Edge enhancement and mask reregistration only
c. Mask reregistration and smoothing only
d. Smoothing, edge enhancement, and mask reregistration
d. Smoothing, edge enhancement, and mask reregistration
What is the fog level for nonradiated unprocessed film?
a. 0.2.0D
b. 2.0.0D
c. 4.2.0D
d. 6.0.0D
a. 0.2.0D
Pick lowest answer
Typically .15 to .2 OD
Line compensation adjust for?
a. The line feedback transformer
b. KV roller variations during the exposure
c. 220 VAC at the output of the high voltage transformer primary
d. Periodic variations in the incoming line voltage
d. Periodic variations in the incoming line voltage
In most cases, manufacturers rate a NiCd battery unusable when capacity drops below what percentage of its original value?
a. 40%
b. 50%
c. 80%
d. 90%
c. 80%
As compared to a film screen cassette, the X-Ray technique setting for a CR cassette must be
a. Lower
b. The same
c. Higher
d. Doubled
a. Lower
-CR imaging plate is more sensitive
If service calls are received at the same time for CT during an abdominal study., CathLab during a pacemaker implant, X-ray during the examination of a femur fracture, and an ER chest pain case using a portable X-Ray, which service should be prioritized first?
a. ER Chest pain
b. CT abdominal Study
c. X-Ray Femur fracture
d. Cath Lab pacemaker implant
d. Cath Lab pacemaker implant
Patient risk of injury or death.
Three phase X-Ray equipment normally requires the feed balanced-to-ground output from what type of distribution transformer
a. Delta
b. Wye
c. Step up
d. Isolation
b. Wye
Secondary has 3 windings connected to common point providing a neutral connection for grounding.
Which of the following are contrast agents used in imaging?
a. Gadolinium, barium sulfate, and iodine
b. Sodium sulfate, barium sulfate, and iodine
c. Silver sulfide, gadolinium, and barium sulfate
d. Sodium chloride, barlium sulfate, and silver sulfate
a. Gadolinium, barium sulfate, and iodine
-Gadolinium, used in MRI for contrast enhancement
-Barium Sulfate, used in X-ray ie GI study
-Iodine, used in various modalities for vascular imaging and enhancement
According to 21 CFR Part 1020, what is the maximum mAs limit for an automatic exposure control unit being operated at or above 51kVp?
a. 60mAs
b. 600mAs
c. 1,200mAs
d. 2,000mAs
600mAs
Increasing the high voltage to a photomultiplier will make it?
a. More sensitive to light
b. More sensitive to heat
c. Less sensitive to artifact
d. Less sensitive to vibration
More sensitive to light
Luminance is measured in
a. NITs
b. curies
c. degrees
d. coulombs
a. NITs
-candelas per square inch
The half value layer is an indication of an X-Ray beam’s
a. Speed
b. Quality
c. Quantity
d. Reaction
b. Quality
A technician measures 0.8Ω ground resistance on a medical device using a safety analyzer. Which of the following should be checked first?
a. Power outlet
b. Safety Analyzer’s probe resistance
c. Power cord and / or plug
d. Power outlet
c. Power cord and / or plug
Technician receives a call from a nurse that the cardiac monitor for a patient is broken, and the monitor will only display lead III even if another lead is selected. Which of the following should the technician recommend first?
a. Check LA electrode
b. Check LL electrode
c. Check RA electrode
d. Request a new monitor
C Check RA electrode
1=LA-RA
2=RA-LL
3=LL-LA
Which of the following is used to control the release of an electron from the space charge region of an electron gun?
a. Grid
b. Anode
c. Cathode
d. Filament
a. Grid
The abruptness of the boundary between two anatomical structures ?
a. Density
b. Blur
c. Contrast
d. Sharpness
d. Sharpness
-How clearly the boundary or edge of a structure is visualized.
While planning electrical power for an X-Ray system impedance should be determined at the
a. Lowest incoming line voltage using the maximum load
b. Highest incoming line voltage using the maximum load
c. Lowest incoming line voltage using the minimum load
d. Highest incoming line voltage using the minimum load
Highest incoming line voltage using the maximum load
The optimal resolution of an LCD panel is
a. Size of the monitor measured diagonally
b. Pixel count of the monitor length by width
c. Lowest resolution the monitor accepts
d. Highest resolution the monitor accepts
Highest resolution the monitor accepts
Which of the following would be considered a therapeutic device as opposed diagnostic device
a. Pacemaker
b. CT Scanner
c. ECG
d. Magnetic resonance imager
a. Pacemaker
When measuring the timer accuracy of a single phase 60hz full wave rectified generator, 12 pulses are measured. What is the decimal time equivalent?
a. 0.01 seconds
b. 0.05 seconds
c. 0.10 seconds
d. 0.20 seconds
c. 0.10 seconds
(120 pulses per second in full wave rectification. 60 pulses per second in a half wave or self rectification.)
On an image intensified fluoroscopic system with SID of 50cm, both the length and the width of the X-Ray field exceeded the visible area of the image receptor by 5cm each. This indicates ?
a. No adjustments are required
b. Length and width errors should be adjusted to 3cm or less each
c. The length error should be adjusted to 2cm or less
d. The sum of the length and width errors should be adjusted to 1 cm or less each
Best Answer:
d. The sum of the length and width errors should be adjusted to 1 cm or less each
1cm is 2% of 50cm
L and W should not exceed visible area by more than 3% in any direction or by 4% in both directions.
An operator has a clinical technique of 90KVP at 100mAs, 40in SID, and an 8:1 ratio grid. What mA would be required when utilizing a standard non-grid cassette?
a. 15 mAs
b. 28.6 mAs
c. 50.8 mAs
d. 100mAs
Best answer is b 28.6
Grid Ration 8:1=mAs factor of 4. Thus 100mAs with grid is lowered to about 25mAs with no grid.
With linear tomography system, an exposure is made which produces a sharp focused image1.0 mm thick where a 10.0mm thick image was expected. The problem was a result of the tube traveling?
a. Too fast
b. Too slow
c. Over too large an angle
d. Over too small an angle
c. Over too large an angle
What is the general purpose of a grid for diagnostic imaging?
Filter scatter radiation and improve image quality
When using a 10:1 ratio grid as apposed to an 8:1 ratio grid, what can you expect the difference
in patient entrance exposure to be?
A 10:1 ratio grid will increase patient dose vs 8:1 grid.
Higher grid ratios have better image quality but also higher dose penalty(Bucky Factor)
What unit of measure in the United States is typically used to define an absorbed dose?
US=rad(Radiation absorbed dose)
International System
(SI)= the gray (Gy)
What is measured by the unit of measure Angstrom?
Unit of displacement, also used to express lengths of wavelength of visible light, UV light, X-rays, and gamma rays.
What part of an x-ray tube does the diagnostic photon energy originate from?
Target Material-Anode
What part of the x-ray tube does the free electron stream originate from?
Cathode
What is the advantage of a rotating anode as apposed to a stationary anode tube?
Heat dissipation
What is the purpose of Half Value Layer?
-Measures beam quality/penetrability.
-Specifically refers to thickness of material needed to reduce the intensity of X-ray beam by half
When and how is high voltage switching utilized in diagnostic imaging?
HV switching is used when applying HV to the X-ray tube.
Switching mechanism controls the timing of the HV applied to tube.
What modalities in Radiology do not use x-ray?
-Ultrasound
-MRI
-Nuclear Medicine
What are the 3 principles of radiation safety?
-Shielding, Time, Distance
STD!
Define the relationship between atomic number and attenuation of a radiation beam.
The higher the atomic number of the material, the greater the ability to attenuate radiation.
Which modality is regulated by MQSA?
Mammography
(Mammography Quality Standards Act)
When utilizing a CR or DR system, what is the significance of the exposure factor number indicated on each image?
Exposure factor referred to as EI, exposure index, or DEI, detector exposure index, provides feedback about Exposure quality assurance, Exposure consistancy, Image Rejection Criteria, and Dose Monitoring.
Per the 2018 ACR Digital Mammography Quality Control Manual, the performance criteria for phantom scoring require visibility of greater than or equal to:
2 fibers, 3 speck groups, 2 masses
1 fiber, 1 speck group, 1 mass
5 fibers, 5 speck groups, 5 masses
3 fibers, 5 speck groups, 7 masses
2 fibers, 3 speck groups, 2 masses
There are three (3) sets of objects within the mammography phantom to simulate structures and objects that might be within a breast. These are the:
masses, threads, and spots
masses, threads, and specks
masses, strings, and spots
masses, fibers, and specks
masses, fibers, and specks
Uncorrected flood field non-uniformities cause __________ artifacts in tomographic reconstruction.
Irregular
Circular
Dropout
Undulating
Circular
All are complications of ultrasound, EXCEPT:
Cavitation
Local heating
Increased risk of tumors in pregnant patients
Mechanical damage to cell membranes
Increased risk of tumors in pregnant patients
Ultrasound interference:
-Always produce a wave form of reduced amplitude
-Are more common with continuous wave ultrasound
-May be of value to ultrasound
-May occur when two waves interact
May occur when two waves interact
Poor magnetic field homogeneity may affect image quality in the following ways:
-Poor fat suppression
-Shading artifacts
-Spatial distortion
-All answers are true
-All answers are true
Pushing the “big red button” near the door to a room housing an MRI scanner:
-Immediately opens the door even if scanning is in progress
-Turns off all electric power to the scanner and room
-Initiates a controlled quench of the magnetic field
-Calls emergency providers (911) and sounds an alarm
-Initiates a controlled quench of the magnetic field
Magnetic field gradients for imaging are typically measured in units of:
Tesla (T)
Gauss per second (G/s)
Millitesla per meter (mT/m):
Tesla per meter per second (T/m-s)
Millitesla per meter (mT/m):
The basic coil configuration used to generate the z-gradient in a cylindrical -MR scanner is known as:
-Double saddle
-Maxwell pair
-Golay
-Fingerprint
-Maxwell pair
Which component of a superconducting MR scanner does not require specialized cooling to maintain function?
-Gradient amplifiers
-Radiofrequency coils
-Main coil windings
-Gradient coils
-Radiofrequency coils
A common location for RF-leakage into the scanner room is:
-Along the junction of copper plates in the scanner room’s walls
-At the penetration panel
-Along seals of the scanner window
-Around the door
-Around the door
Artifacts in an MRI can be the result of all the of following execpt?
a. RF interference
b. Signal averaging
c. Aliasing
d. Distortions
b. Signal averaging
What is used to ensure the magnetic field is as close as possible to isocenter?
1. Shims 2. Gradient coils 3. RF coil 4. Gauss line
- Shims
These substances exhibit a very slight negative or repelling effect when placed in externally applied magnetic field. They have low and negative susceptibility.
A. Diamagnetic B. Paramagnetic C. Superparamagnetic D. Ferromagnetic
A. Diamagnetic
Diamagnetic material have low and negative magnetic susceptibility, meaning they generate a magnetic field in the opposite direction to the applied field. Wood, water, plastic, and some metals like copper are examples of diamagnetic material.
Which of the following commonly encountered postoperative items should be further scrutinized as a potential MR safety hazard:
1. Skin staples 2. IV catheter and tubing (no metal clamps) 3. EKG Pads (non certified) 4. Penrose drain
- EKG Pads (non certified)
Which aspect is crucial for ensuring patient safety and image quality in mammography?
A) Utilizing Higher KV technique to improve image quality B) Optional compression of breast tissue C) Adherence to standardized positioning protocols D) Utilization of high-frequency ultrasound waves
C) Adherence to standardized positioning protocols
Although breast __________ are usually noncancerous (benign), certain patterns — such as tight clusters with irregular shapes and fine appearance — may indicate breast cancer or precancerous changes to breast tissue.
-calcifications
-lobules
-cysts
-glandular lobules
-calcifications
A grid is used in mammography (as in other x-ray procedures) to absorb scattered radiation and improve contrast sensitivity. Compared to grids for general x-ray imaging, grids for mammography have a __________ ratio, and the material between the strips is selected for __________ x-ray absorption.
Higher, high
Lower, high
Higher, low
Lower, low
-Lower, low
Good __________ of the breast is one of the essentials of effective mammography (and a common source of patient discomfort and concern).
-image processing
-filtration
-image quality
-compression
-compression
Whereas most x-ray machines use aluminum or “aluminum equivalent” to filter the x-ray beam, mammography uses filters that work on a different principle and are used to enhance contrast sensitivity. Some systems allow the operator (or automatic control function) to select either __________ or a __________ filter to optimize the spectrum for specific breast conditions.
-molybdenum, rhodium
-aluminum, copper
-lead, graphite
-molybdenum, copper
-molybdenum, rhodium
Most signs of breast pathology are in the form of soft-tissue masses that are:
-not very different from the surrounding tissue
-distinct from the surrounding tissue
-of higher contrast
-visible only under high kV x-ray
-not very different from the surrounding tissue
Mammography requires the highest __________ of all x-ray procedures.
-average energy
-peak energy
-beam penetration
-image quality
image quality
The typical MRI has a magnetic strength in the range of:
12 – 24 Tesla
3 – 6 Tesla
1.5 – 3 Tesla
6 – 12 Tesla
1.5 – 3 Tesla
The cryogen used for the MRI superconducting magnet is:
Liquid oxygen
Xenon
Liquid nitrogen
Liquid helium
Liquid helium
The bulk magnetic properties of matter derive primarily from:
Protons
Electrons
Neutrons
Whole nuclei
Protons
The direction of magnetic field lines surrounding a wire can be determined using?
Faraday’s Law
Lenz’ Law
The left-hand rule
The right-hand rule
The right-hand rule
The basic coil configuration used to generate the z-gradient in a cylindrical MR scanner is known as:
Golay
Fingerprint
Maxwell pair
Double saddle
Maxwell pair
The units for slew rate are given in:
Tesla per second (T/s)
Tesla per meter per second (T/m/s)
Millitesla per meter (mT/m)
Milliseconds (ms)
Tesla per meter per second (T/m/s)
-Slew Rate is rate at which the magnetic field gradients can be switched. Higher slew rate allows for faster image sequences and higher image quality.
The fringe fields of cylindrical superconducting magnet are highest:
In the x-direction (transverse and horizontal to the axis bore)
They are equal in all directions
In the z-direction (along the axis bore)
In the y-direction (transverse and vertical to the axis bore)
In the z-direction (along the axis bore)
A device that allows a plastic oxygen hose to be passed through the wall of an MR scanner room without disrupting the integrity of the RF-shielding is called a:
Faraday cage
Penetration panel
Waveguide
Bandstop filter
Waveguide
Fiber optic cables, hoses for pneumatic (air) or hydrolic (liquid) system can pass through the penetration panel via the wave guides.
As ultrasound frequency increases:
imaging depth decreases
propagation speed decreases
imaging depth increases
wavelength increases
imaging depth decreases
As ultrasound frequency increases, the attenuation coefficient:
decreases
attenuation coefficient not affected by frequency
increases
stays the same
increases
Which one of the following quantities varies the most with distance from the transducer face?
Axial resolution
Lateral resolution
Wavelength
Frequency
Lateral resolution
) ( ) ( ) ( ) *( )** ( ) * ) Lateral Spatial
The best Ultrasound image resolution is obtained:
At the transducer surface
In the focal zone
In the near field
In the far field
In the focal zone
The lateral resolution of a transducer is primarily determined by:
the beam width
applied voltage
the acoustic impedance of tissue
spatial pulse length
the beam width
The characteristic(s) of computed tomography (CT) which give(s) it a distinct advantage over conventional radiography is/are:
Better contrast sensitivity
Fewer artifacts.
Lower noise.
Higher visibility of detail
Better contrast sensitivity (low contrast detectability)
Two x-ray energies are used in DEXA bone densitometry in order to:
-Find the optimal energy to image the bones
-Cancel out soft tissue attenuation
-Decrease radiation dose
-Determine the minerals present in the bones (calcium vs. phosphorus)
Cancel out soft tissue attenuation
A hardened beam has what effect on the CT appearance of soft tissue:
Darker with poorer contrast
Darker with better contrast
No change
Brighter with the same contrast
Darker with poorer contrast
Beam hardening in x-ray imaging refers to:
-Increase in a photon’s energy as it is scattered by a dense material
-Increased average x-ray energy as a beam passes through a dense material
-Decreasing x-ray beam strength as it passes through a dense material
-Decreased average x-ray energy as a beam passes through a dense material
Increased average x-ray energy as a beam passes through a dense material
Iodine is a good CT contrast agent because:
-It simulates the attenuation of bone
-The k-edge (33 keV) is near the average diagnostic x-ray energy produced by a 120 kV tube
-The k-edge (33 keV) is much lower than x-ray energies produced by a 120 kV tube
-We can achieve very high concentrations in target organs
The k-edge (33 keV) is near the average diagnostic x-ray energy
produced by a 120 kV tube
The major determinant of temporal resolution in CT is:
Fan-beam angle
Reconstruction algorithm
Gantry rotation speed
Detector collimation
Gantry rotation speed
In soft tissue, Compton scattering becomes the most important interaction process above:
5 keV.
75 keV.
25 keV.
50 keV.
25 keV.
The intensity of an X-ray beam increases and the subject contrast remains unchanged by:
Increasing the kVp.
Decreasing the filtration in the beam.
Changing from a single phase generator to a three phase one.
Increasing the exposure (mAs).
Increasing the exposure (mAs).
As the kV is increased, the contrast between soft tissue and bone seen in a radiographic image:
Decreases regardless of the choice of image receptor.
Increases up to 69.5 kV but then remains constant.
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.
In comparison with a single phase HV generator of the same kVp, the effective energy of the X-rays from a medium frequency generator is:
Twice.
Higher.
Lower.
The same.
Higher.
The anode of a diagnostic X-ray tube is angled:
-To create higher beam homogeneity.
-To allow the escape of some of the X-ray photons which are emitted perpendicular to the direction of the electron current
-To give a smaller actual focal spot.
-To give a smaller effective focal spot.
To allow the escape of some of the X-ray photons which are emitted perpendicular to the direction of the electron current
For fixed kVp and filtration, which will produce a beam with the largest Half Value Layer (HVL):
Constant potential generator.
The HVL would be the same for all three.
Single phase generator.
Mobile capacitor discharge unit.
Constant potential generator.
The design of an intensifying screen is a compromise between the twin desires of low patient dose and low quantum mottle. Which of the options below best satisfies this compromise:
High detection efficiency and high conversion efficiency.
Low detection efficiency and low conversion efficiency.
High detection efficiency and low conversion efficiency.
Low detection efficiency and high conversion efficiency.
High detection efficiency and high conversion efficiency.
The scattered radiation during a diagnostic X-ray examination arises mainly as a result of the:
Photoelectric absorption.
Compton effect.
Coherent scattering.
All of these.
Compton effect.
The finite size of the X-ray tube focal spot gives rise to:
Penumbra
Quantum mottle.
Magnification.
Pseudo-linear transformation.
Penumbra
The X-ray tube current (mA) influences which ONE of the following parameters:
Patient penetration
Number of X-ray photons
Maximum X-ray energy
Mean energy (quality) of the X-rays
Number of X-ray photons
When a filter is used to harden a diagnostic energy X-ray beam, it does so mainly by:
Compton effect.
Photoelectric absorption.
Coherent scattering.
Unaltered scatter.
Photoelectric absorption.
An X-ray beam with a high HVL is:
Likely to result in a larger skin absorbed dose.
Said to be more penetrating.
Less likely to produce scatter.
Said to be soft.
Said to be more penetrating.
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:
None of above.
Pair.
Photoelectric effect.
Compton effect.
Photoelectric effect.
The inverse square law relationship between radiation intensity and distance from a point source of radiation (e.g. XRT focal spot) is due to:
Scatter in air.
Absorption in air.
Divergence of the X-ray beam.
Chance.
Divergence of the X-ray beam.
The number of gray shades that an imaging system can reproduce is called its __________.
spatial resolution
contrast
spatial frequency
dynamic range
dynamic range
In digital imaging, spatial resolution is ultimately limited by?
focal spot size
spatial frequency
contrast resolution
pixel size
pixel size
The output signal from the photostimulable phosphor plate is converted from analog to digital by the?
ADC
optical system
photodetector (PM tube)
drive mechanism
ADC
Computed radiography uses (a) __________ for latent image formation.
thin film transistors
photosensitive silicon chips
semiconductor material
photostimulable phosphor
photostimulable phosphor
The phosphor most likely to be used in indirect digital radiography is:
A-Si
CsI
a-Se
NaI:Tl
CsI (Cesium Iodide)
The area of the TFT that is capable of recording information in comparison to the portion of the TFT that houses electronics is referred to as:
DQE
Fill factor
Pixel pitch
None are correct
Fill factor
With regard to computed radiographic (CR) imaging:
-Unlike photographic film, CR plates are impervious to “fogging” by background radiation during storage.
-Good quality diagnostic images can be acquired with radiation exposures which are similar to those required for film/screen imaging.
-An automatic exposure control (AEC) is not required.
-Images with the same CR exposure index are all obtained with the same radiation dose to the patient.
-Good quality diagnostic images can be acquired with radiation exposures which are similar to those required for film/screen imaging
In DR, where are the electrical charges stored?
Thin Film Transistors TFTs
Titanium Film Transistors TFTs
Thin Photodiode Transistors TPTs
Thin Plate Transistors TPTs
Thin Film Transistors TFTs
The CR imaging plate reader uses a laser to scan the imaging plate, releasing the energy stored in the conductive layer as ______ light.
White
Ultraviolet
Infrared
Blue
Blue
The process of scanning the moving CR imaging plate is known as:
Transition
Digitization
Translation
Raster scanning
Transition
What are the layers of a CR Imaging Plate?
-Protective, phosphor, conductor, support, shield, backing
-Protective, Conducive, Reflective, Protective, Intensifying screen
-Phosphor, conductive, support, reflective, intensifying screen
-Protective, phosphor, reflective, support
Protective, phosphor, conductor, support, shield, backing
CRES question
What is a scintillator?
Absorbs light and converts to gamma rays
Absorbs light and converts energy to x-rays
Absorbs x-rays and converts to carbon
Absorbs x-rays and converts energy to light
Absorbs x-rays and converts energy to light
The “latent image” in a CR imaging plate is stored by the:
Sensitivity speck
Photomultiplier tube
Trapped electrons in phosphor center
Analog to digital converter
Trapped electrons in phosphor center
Poor magnetic field homogeneity may affect image quality in the following ways:
Poor fat suppression
Spatial distortion
Shading artifacts
All answers are true
All answers are true
What is the order of operation of a film processor after film is inserted?
Developer->Fixer->Water Rinse->Dryer
Decreasing kV in CT is advantageous because:
Scan times are reduced
X-ray penetration improves
Tissue contrast improves
Metal streak artifacts are improved
Tissue contrast improves
An accurate, modern CT scanner is capable of spatial resolution of up to _________:
20 lp/cm
10 lp/mm
100 lp/cm
20 lp/mm
20 lp/cm
Which of the following numbers reported by the scanner best reflects the total amount of radiation delivered to the patient?
Effective mAs
Pitch
Dose-length product (DLP)
CT Dose Index (CTDI)
Dose-length product (DLP)
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:
halve
remain the same
double
quadruple
quadruple
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.
minified; decrease
magnified; increase
minified; increase
magnified; decrease
magnified; increase
A grid is used in mammography (as in other x-ray procedures) to absorb scattered radiation and improve contrast sensitivity. Compared to grids for general x-ray imaging, grids for mammography have a __________ ratio, and the material between the strips is selected for __________ x-ray absorption.
Lower, high
Higher, high
Higher, low
Lower, low
Lower, low
An appropriate kV range for mammography would be:
24kV to 32kV
35kV to 50kV
50kV to 75kV
7kV to 15kV
24kV to 32kV
Per the 2018 ACR Digital Mammography Quality Control Manual, the performance criteria for phantom scoring require visibility of greater than or equal to:
2 fibers, 3 speck groups, 2 masses
1 fiber, 1 speck group, 1 mass
5 fibers, 5 speck groups, 5 masses
3 fibers, 5 speck groups, 7 masses
2 fibers, 3 speck groups, 2 masses
In order to decrease dose in large mammo patients:
Decrease kV and improve image noise
Increase kV and improve image contrast
Increase kV and improve image noise
Decrease kV and improve image contrast
Increase kV and improve image noise
Iodine is an effective contrast agent because:
-It has a high likelihood of Compton interaction at diagnostic x-ray
energies
-It has a high mass density
-It has a high electron density
-It has a high likelihood of photoelectric interaction at diagnosticx-ray energies
-It has a high likelihood of photoelectric interaction at diagnostic x-
ray energies
The part of the image intensifier tube that functions to change the visible light image into an electronic image is the:
Focusing lens
Photocathode
Input phosphor
Output phosphor
Photocathode
The usual range of mA required for an image intensified fluoroscopy is about:
25-100 mA
6-10 mA
100-600 mA
1-5 mA
1-5 mA
The concept of clinical SPECT/CT system can be described as:
A CT scanner positioned in front of a single-head scintillation camera
A CT scanner positioned in front of a dual-head scintillation camera
A dual-head scintillation camera positioned in front of a CT scanner
A single-head scintillation camera positioned in front of a CT scanner
A dual-head scintillation camera positioned in front of a CT scanner
The process of aligning images so that corresponding features can easily be related is called:
Image smoothing
Image processing
Image registration
Image filtering
Image registration
False-negative PET scans in lung cancer imaging occur predominantly because of:
Lesions that are too superficial to be evaluated by PET
Lesions that are too big to be evaluated by PET
Lesions that are too small to be evaluated by PET
Lesions that are too deep to be evaluated by PET
Lesions that are too small to be evaluated by PET
In the PET/CT acquisition, the CT component is performed for?
Scatter correction
Motion correction
Attenuation correction
Random correction
Attenuation correction
The property of the scintillation detector described as the number of scintillations produced by each incident photon is called:
The decay constant
Energy resolution
The stopping power
The light output
The light output
In PET scanning process raw data acquired and identified as coincidence events along their line of response (LOR) are stored in the raw data format called:
Sinograms
Dextrograms
Pictograms
Histograms
Sinograms
The positron has the same mass as an electron and an electric charge of:
+1
0
−1
–2
+1
The sum of the weighted equivalent doses in all the tissues and organs of the body is called:
Shallow dose equivalent
Committed dose equivalent
Whole-body dose
Effective dose
Effective dose
PET tracers have demonstrated significant potential utility and application in the following clinical areas EXCEPT:
Oncology
Neurology
Pulmonology
Cardiology
Pulmonology
Truncation artifacts in PET/CT imaging are produced by?
Contrast medium
Difference in size of FOV between PET and the CT
Difference in scanning time between PET and the CT
Beds overlapping
Difference in size of FOV between PET and the CT
The exposure rate of an activity of 1 millicurie (mCi) measured at 1 centimeter (cm) is called?
Roentgen man equivalent (REM)
Total effective dose equivalent (TEDE)
Kilobecquerel (kBq)
The exposure rate constant (ERC)
The exposure rate constant (ERC)
The detector of PET is made of _________
Gadolinium
Silver
Lead
Tungsten
Gadolinium
What makes PET and SPECT so unique when it comes to nuclear imaging?
Do not require X – Rays
They give more details about the imaged organ/tissue
They show metabolic functions
Do not require dyes
They show metabolic functions
What does the ‘P’ in SPECT stand for?
Positron
P – orbital
Proton
Photon
PHOTON
SPECT = Single Photon Emission Computed Tomography
Which of the following isotopes is not a radioisotope?
Sulphur-35
Carbon-13
Tritium
Carbon-14
Carbon-13
Which of the following detection methods is not commonly used to detect isotopically labelled drug metabolites?
Mass spectrometry
Nuclear magnetic resonance spectroscopy
Scintillation counting
Infrared spectroscopy
Infrared spectroscopy
What is detected during positron emission tomography (PET)?
Positrons
Neutrons
Electrons
Photons
Photons
Which of the following components is where a gamma camera adds all the signals in order to determine where each scintillation event occurred in the detector?
Position circuitry
Detector crystal
Collimator
Photo multiplier tubes
Position circuitry
What does the ‘P’ in PET stand for?
Proton
Positron
P – orbital
Photon
Positron
PET: Positron Emission Tomography: nuclear imaging technique to produce detailed, 3D images of the inside of body.
Detects gamma rays produced with collisions of decayed isotope with electrons in the body. 2 gamma rays produced with each collision.
Tissue contrast is generated by what type of interaction?
Coherent (Rayleigh) scatter
Photoelectric effect
Beam hardening effect
Incoherent (Compton) scatter
Photoelectric effect
In order to decrease dose in large patients:
Decrease kV and improve image contrast
Increase kV and improve image contrast
Decrease kV and improve image noise
Increase kV and improve image noise
Increase kV and improve image noise
-Increased KV with shorter exposure to control dose.
Switching from a molybdenum to a tungsten anode demonstrates what trade-off?
Lower dose, worse contrast
Higher dose, better contrast
Lower dose, worse heat capacity
Higher dose, better heat capacity
Lower dose, worse contrast
Whereas most x-ray machines use aluminum or “aluminum equivalent” to filter the x-ray beam, mammography uses filters that work on a different principle and are used to enhance contrast sensitivity. Some systems allow the operator (or automatic control function) to select either __________ or a __________ filter to optimize the spectrum for specific breast conditions.
molybdenum, rhodium
The number of gray shades that an imaging system can reproduce is called its __.
dynamic range
