| Question | Answer |
| What are the grid conversion ratios? | -No grid=1
-5:1=2
-6:1=3 **Equivalent to air gap technique
-8:1=4
-10:1/12:1=5
-16:1=6
(Williams Math Review, 2021) |
| What is the formula for mAs? | mA x Seconds= mAs
(Williams Math Review, 2021) |
| What is the 15% rule? | ***Applies only to 60-100 kVp range ONLY
-Increase kVp 15%, divide mAs by 2
-Decrease kVp by 15%, multiply mAs by 2
(Williams Math Review, 2021) |
| What are the relationships of SID, SOD, and OID? | -SOD+OID=SID
-SID-OID=SOD
-SID-SOD=OID
(Williams Math Review, 2021) |
| What is the Inverse square law? | (I1)/(I2)=(d2)^2/(d1)^2
(Williams Math Review, 2021) |
| What is the Direct square law? | "old" mAs1/"new"mAs2=(d1)^2/(d2)^2
(Williams Math Review, 2021) |
| What is the Unsharpness formula? | Filament size X OID/SOD=Unsharpness
(Williams Math Review, 2021) |
| How do you figure out the Grid Ratio? (formula) | Height of Grid material/ Width of Interspace= Grid Ratio
(Williams Math Review, 2021) |
| What is the Grid conversion formula? | mAs1/mAs2=Conversion Factor 1/Conversion Factor 2
(Williams Math Review, 2021) |
| What are the field size multipliers? | mAs1/mAs2=From/To
14"x17= 1
10"x12"= 1.25
8"x10" OR 9"x9"= 1.40
(Williams Math Review, 2021) |
| What is the magnification formula? | SID/SOD=MF
Image size/Object size= MF
***Fluoro
Old input screen size/New input screen size= Fluoro MF
(Williams Math Review, 2021) |
| What is the percentage of magnification factor formula? | Image size- Object size/ Object size X 100= %
(Williams Math Review, 2021) |
| What is the formula for patient dose increase in fluoro? | Input phosphor #1^2/ Input phosphor #2^2= Pt dose increase
(Williams Math Review, 2021) |
| What is the formula for minification gain? | Input Phosphor Diameter^2/Output Phosphor Diameter^2= Mini. Gain
(Williams Math Review, 2021) |
| What is the formula for brightness gain? | Magnification gain X Flux gain= brightness gain
(Williams Math Review, 2021) |
| What is the formula for Heat Units? | # of exposures X kVp X mA X seconds X GENERATOR= Heat Untis
(Williams Math Review, 2021) |
| What is the multiplication factors for the heat unit formula based on generator? | Single Phase= 1
3 Phase, 6 Pulse= 1.35
3 Phase, 12 Pulse/High Frequency= 1.41
(Williams Math Review, 2021) |
| As DQE goes _______, patient dose goes _______? | Up, Down
(Image Acquisition Worksheet Day 2, 2021) |
| EI is ______________ to the exposure of the image receptor? | Directly proportional
(Image Acquisition Worksheet Day 2, 2021) |
| S-number is _________________ to the exposure of the image receptor? | Inversely proportional
(Image Acquisition Worksheet Day 2, 2021) |
| What is contrast resolution? | Ability of a digital imaging system to display changes in gray values; bit depth
(Image Acquisition Worksheet Day 2, 2021) |
| What is spatial resolution? | Ability of a system to record adjacent small structures; measured in line pairs/mm
(Image Acquisition Worksheet Day 2, 2021) |
| What is MTF? | Describes the contribution of all system components
(Image Acquisition Worksheet Day 2, 2021) |
| What are the technique considerations for casts? | -Wet/Plaster= 100% mAs/8-10 kVp
-Dry= 5-7 kVP
-Fiberglass= 3-4 kVp
(Image Acquisition Worksheet Day 2, 2021) |
| What is DICOM? | Digital Imaging and Communications in Medicine
interconnects medical digital imaging devices
(Image Acquisition Worksheet Day 2, 2021) |
| What is PACS? | Picture Archival Communication System
Where all digital images are stored
(Image Acquisition Worksheet Day 2, 2021) |
| What is RIS? | Radiology Information System
Order entry, pt demographic information
(Image Acquisition Worksheet Day 2, 2021) |
| What is HIS? | Hospital Information System
Pt demographic information, billing, supplies, order entry for testing
(Image Acquisition Worksheet Day 2, 2021) |
| What is EMR/EHR? | Electronic Medical/Health Record
Pt medical charts, Medication administration record, supply chain
(Image Acquisition Worksheet Day 2, 2021) |
| What is the single greatest source of acute radiation exposure in diagnostic imaging? | Fluoroscopy
(Equipment Operation and Quality Control 2, 2021) |
| How is image quality evaluated? | According to image brightness, grayscale, spatial resolution, and distortion
(Radiography Prep, pg. 313) |
| What are the visibility factors? | Brightness and grayscale
(Radiography Prep, pg. 313) |
| What are the geometric factors? | Spatial resolution and distortion
(Radiography Prep, pg. 313) |
| What are the prime exposure/technical factors used to create an image? | milliamperage (mA), exposure time (s), kilovoltage (kV), and SID
(Radiography Prep, pg. 313) |
| What do digital radiographic images require? | Large amount of digital storage space
High-bandwidth in PACS
High-resolution display monitors
(Radiography Prep, pg. 313) |
| In Digital Imaging, what does kV affect? | Penetration
(Radiography Prep, pg. 313) |
| In Digital Imaging, mAs determines what? | Dose/receptor exposure
(Radiography Prep, pg. 313) |
| How are brightness and contrast determined in digital imaging? | By computer software and monitor controls
(Radiography Prep, pg. 313) |
| State 3 advantages of digital imaging. | Image manipulation permits visualization of structures not seen in analog imaging.
Digital IRs respond to a wide range of exposures; provide a wide dynamic range
Digital images can be shared and/or sent to distant locations
(Radiography Prep, pg. 313) |
| Define long-scale and short-scale contrast. | Long-scale: Low contrast; lots grays
Short-scale: High contrast; few grays
(Radiography Prep, pg. 314) |
| What is the function of contrast? | To make details visible
(Radiography Prep, pg. 314) |
| What does brightness refer to? | Principally to the amount of light transmitted by the display monitor
(Radiography Prep, pg. 314) |
| What does subject contrast refer to? | Various body tissue densities and thicknesses, which result in differential absorption of the x-ray beam and signal differences within the remnant beam
(Radiography Prep, pg. 314) |
| What is the Reciprocity Law? | Any combination of mA and exposure time that will produce a particular "mAs" will produce identical receptor exposure
(Radiography Prep, pg. 315) |
| What are 3 factors that determine production of scattered radiation? | 1. Field size/beam restriction
2. Kilovoltage
3. Thickness/volume and density of tissues
(Radiography Prep, pg. 318) |
| A 6 inch Air-gap is the equivalent to which grid ratio? | 8:1 grid
(Radiography Prep, pg. 320) |
| X-ray photons can do what 3 things? | 1. Penetrate through the part
2. Scatter within the part
3. Be absorbed by the part
(Radiography Prep, pg. 321) |
| When should a grid be used? | When the body part is thicker than 10 cm
(Radiography Prep, pg. 321) |
| Grids can be what? | 1. Parallel or focused
2. Stationary or moving
(Radiography Prep, pg. 323) |
| What are the 5 Grid errors? | 1. Angulation error: angled against lead strips
2. Off-level error: grid surface must be perpendicular to the CR
3. Off-focus error: if the SID is outside lower OR upper limits
4. Off-center error
5. Upside-down grid
(Radiography Prep, pg. 323-324) |
| What is the minimum filtration requirement for x-ray tubes operated above 70 kVp? | 2.5 mm Al equivalent
(Radiography Prep, pg.328) |
| Name a few additive pathologic conditions. | Ascites
R.A.
Paget's disease
Pneumonia
Atelectasis
CHF
Edematous tissue
(Radiography Prep, pg. 331) |
| Name a few destructive pathologic conditions. | Osteoporosis
Osteomalacia
Pneumoperitoneum
Emphysema
Degenerative arthritis
Atrophic and necrotic conditions
(Radiography Prep, pg. 331) |
| Name 3 Anode heel effect conditions. | At short SID
With large-size Its
With small anode angle x-ray tubes
(Radiography Prep, pg. 332) |
| State the % ripple for each generator.
-Single phase
-3 Phase, 6 pulse
-3 Phase, 12 pulse
-High Frequency | Single phase: 100%
3 phase, 6 pulse: 13%
3 phase, 12 pulse: 3-4%
High Frequency: <1%
(Radiography Prep, pg. 333) |
| What is the smallest unit of computer data? | Bit
(Radiography Prep, pg. 334) |
| What is bit depth? | Number of bits per pixel
(Radiography Prep, pg. 334) |
| What do window width and window level correspond to? | Width: controls shades of gray
Level: controls brightness
(Radiography Prep, pg. 334-335) |
| What are causes for image graininess? | Underexposure
Incorrect processing algorithm/LUT
Excess scattered radiation
Inadequate beam restriction
Grid misalignment; cutoff
(Radiography Prep, pg. 337) |
| What are the 2 types of AEC? | Phototimer
Ionization Chamber
(Radiography Prep, pg. 337) |
| Digital image resolution improves with what? | Smaller pixel size
Smaller pixel pitch
Larger image matrix
Greater pixel density
(Radiography Prep, pg. 348) |
| What is Detective Quantum Efficiency (DQE)? | Describes the percentage of incoming x-ray photons that are detected and absorbed by the detector for transformation to the x-ray image
(Radiography Prep, pg. 349) |
| What is quantum mottle? | Insufficient number of x-ray photons resulting in noise appearing as graininess
(Radiography Prep, pg. 350) |
| What are factors that affect resolution? | -OID (magnification)
-SID (magnification)
-Focal Spot Size (F.S. blur)
-Patient factors (shape/position)
-Motion (motion blur)
(Radiography Prep, pg. 350) |
| What are 2 types of image distortion? | -Size (magnification)
-Shape (elongation/foreshortening)
(Radiography Prep, pg. 350) |
| What is the information required on each x-ray image? | -Patient name/ ID number
-Side marker, R or L
-Examination date
-Institution's name
(Radiography Prep, pg. 368) |
| When is shielding evident? | When reproductive organs are in the collimated primary beam OR within 5 cm of it
(Radiography Prep, pg. 368) |
| What is aliasing "Moire effect"? | If the direction of the lead strips and the grid lines per inch match the scan frequency of the scanner/reader
(Radiography Prep, pg. 373) |
| With PSP plates, if they have been inactive for more than 48 hours, what needs to happen? | Should be erased prior to use
(Radiography Prep, pg. 374) |
| What is the Nyquist theorem? | When the electric signals are sampled for conversion to a digital image, the sampling frequency must be more than twice the frequency of the input signal in order to best duplicate that original signal
(Radiography Prep, pg. 375) |
| Digital imaging has what type of dynamic range/latitude? | Wide
(Radiography Prep, pg. 380) |
| What is shuttering used for? | To remove the bright unexposed areas outside of the collimated field that contribute to veil glare
(Radiography Prep, pg. 380) |
| Which detector systems have the highest DQE? | a-Se TFT's used in direct-capture systems
(Radiography Prep, pg. 382) |
| Bremsstrahlung "braking" radiation comprise _______ % of the x-ray beam? | 70-90%
(Radiography Prep, pg. 388) |
| Characteristic radiation occurs at the minimum keV and comprises how much of the x-ray beam? | 70 keV
10-30%
(Radiography Prep, pg. 388) |
| What is the velocity of an x-ray? | 186,000 miles a second (3 x 10^8 m/s)
(Radiography Prep, pg. 389) |
| When is the photoelectric effect most likely to occur? | In absorbers with a high atomic number
(Radiography Prep, pg. 391) |
| What does Compton scatter contribute to an image and pose to personnel? | Image fog
Radiation hazards (in Fluoro procedures)
(Radiography Prep, pg. 391) |
| Do X-rays have an electrical charge? | No, they are electrically neutral
(Radiography Prep, pg. 391) |
| What effect do x-rays have on the air? | Ionizing effect
(Radiography Prep, pg. 391) |
| Classical scatter is also known as and occurs with what? | Coherent, unmodified, Rayleigh scatter
With very-low energies, scatters other ways, no ionization occurs
(Radiography Prep, pg. 392) |
| What is the function of a generator? | To change mechanical energy to electrical energy
(Radiography Prep, pg. 394) |
| What are X-ray transformers used for? | To increase the incoming voltage to the more useful kilovoltage required for x-ray production
(Radiography Prep, pg. 397) |
| Autotransformers operation on the principle of? | Self-Induction
(Radiography Prep, pg. 398) |
| What do transformers & autotransformers require for operation? | AC (alternating current)
(Radiography Prep, pg. 399) |
| What principle do transformers operate on? | Mutual induction
(Radiography Prep, pg. 399) |
| What is the X-ray tube comprised of? | Anode (+)
Cathode (-)
Glass envelope (vacuum)
(Radiography Prep, pg. 408) |
| What does the anode consist of? | Graphite/molybdenium disk with beveled edge
Tungsten/rhenium alloy focal track (0.6-1.2 mm)
Molybdenium stem (support for anode disk
(Radiography Prep, pg. 408) |
| The induction motor does what? and is composed of what 2 things? | Rotates anode
Stator (outside glass envelope)
Rotor (inside glass envelope)
(Radiography Prep, pg. 408 |
| What are 3 characteristics of Tungsten (W)? | High atomic # Z=74
High melting point= 3410 Celsius
Thermal conductivity for heat dissipation
(Radiography Prep, pg. 408) |
| The filament is heated with what required A and V? | 3-5 A
10-12 V
(Radiography Prep, pg. 408) |
| During the production of x-rays, how much of the kinetic energy is converted to x-rays? | 0.2%
the rest is converted to heat
(Radiography Prep, pg. 410) |
| What is the line focus principle? | The effective focal spot is always smaller than the actual focal spot
(Radiography Prep, pg. 411) |
| What % must collimators be accurate of the SID? | 2%
(Radiography Prep, pg. 413) |
| What are 4 causes of X-ray tube failure? | 1. Vaporized Tungsten
2. Pitted Anode
3. Cracked Anode
4. Gassy Tube
(Radiography Prep, pg. 415-416) |
| What are the types of X-ray timers? | Mechanical
Synchronous
Impulse
Electronic
mAs
AEC
(Radiography Prep, pg. 422) |
| What are the components of the Primary/Low-Voltage circuit? | Main Switch/Circuit breaker
Autotransformer
kV selector switch
Line voltage compensator
Timer
Primary coil of high voltage transformer
Exposure switch
(Radiography Prep, pg. 424) |
| What are the components of the Secondary/High-Voltage circuit? | Secondary coil of the high-voltage transformer
mA meter (grounded at midpoint of the secondary coil)
Rectifiers
X-ray tube
(Radiography Prep, pg. 425) |
| What are some advantages of Flat Panel Fluoroscopy? | Pulsed x-ray beam
Decreased patient dose
Increased sensitivity to x-rays (DQE)
Increased temporal resolution; decreased motion unsharpness
Improved contrast resolution
(Radiography Prep, pg. 451) |
