Final Flashcards
In what year were some of the biologically damaging effects of x-rays discovered?
1898
In what year were x-rays discovered?
1895 (Wilhelm Conrad Roentgen)
X-rays were discovered in experiments dealing w/ electricity & ___?
Vacuum tubes (Crooke’s tubes)
X-rays were discovered when they caused a barium platinocyanide plate to?
Fluoresce
X-radiation is part of the _____ spectrum?
Electromagnetic
X-rays have a dual nature, which means that they behave like both…
Waves & particles
The wavelength & frequency of x-rays are ____ related?
Inversely
X-rays have a(n) ____ electrical charge
No charge
X-rays have \_\_\_\_\_\_ A. no mass B. the same mass as electrons C. the same mass as protons D. the same mass as neutrons
A. No mass
The x-ray beam used in diagnostic radiography can be described as being ______
Polyenergetic
Which X-ray tube component serves as a source of electrons for x-ray productions?
Filament
Electrons interact with the ______ to produce x-rays & heat
Target
The cloud of electrons that forms before x-ray production is referred to as?
Space charge
The burning off of electrons at the cathode is referred to as?
Thermionic emission
Which primary exposure factor influences both the quantity & the quality of x-rays photons?
kVp
The unit used to express tube current is?
mA
What percentage of the kinetic energy is converted to heat when moving electrons strike the anode target?
99%
The intensity of the x-ray beam is greater on the ?
Cathode side of the tube
According to the line focus principle, as the target angle decreases, the ______?
Effective focal spot size decreases
____ will extend X-ray tube life
Warming up the tube after 2 hours of non-use
The process whereby a radiographic image is created by passing an x-ray beam through anatomical tissue is known as?
Differential absorption
Which of the following processes occurs during beam attenutation: 1) absorptions, 2) photon transmission, or 3) scattering?
1,2, & 3
The ability of an x-ray photon to remove an atom’s electron is a charac. known as?
Ionization
The x-ray interaction responsible for absorption is ?
Photoelectric
The x-ray interaction responsible for scattering is?
Compton
Exit radiation is composed of which of the following: 1) transmitted radiation, 2) absorbed radiation, or 3) scattered radiation?
1 & 3 only
What interaction creates unwanted density known as fog?
Compton
The low-density areas on a radiographic image are created by?
Absorbed radiation
An anatomic part that transmits the incoming x-ray photon will create an area of ___ on the radiographic image
High density
Development & processing of an exposed film will result in a(n)
Manifest image
A radiograph that needs no improvement is defined as?
Optimal
Factors that affect visibility of a radiographic image are known as?
Photographic
A radiograph that has insufficient density would best be described as?
Underexposed
Which of the following is equivalent to doubling the mAs?
increase the kVp by 15%
A radiograph was taken using 65kVp, 200mA at 0.10s. The image needs to be repeated b/c it is too dark. What exposure technique adjustment would be best?
65kVp, 200mA at 0.05s
What is the relationship b/w milliamperage & exposure time to maintain density?
Inverse
When repeating a radiograph to correct for a density error, it is recommended to adjust the mAs by a factor of?
2
Which of the following when decreased will increase density: 1) grid ratio, 2) focal spot, or 3) part thickness?
1 & 3 only
How will radiographic density be affected when the SID is decreased by half?
Increased
A radiographic image described as having too many shades of gray would be?
Low contrast
The visible differences b/w adjacent radiographic densities defines
Contrast
Which of the following will increase radiographic contrast?
Increasing the grid ratio
Radiographic contrast can be increased by
Adding contrast media
What factor has the most direct effect on radiographic contrast?
kVp
Recorded detail is defined as?
Accuracy of structural lines recorded
Using a smaller focal spot size will have what effect on the radiographic image?
Increase recorded detail
Shape distortion can be created by ?
Angling the CR
The projected shape of the unrestricted primary beam is?
Circular
The purpose of beam restricting devices is to _____ by changing the size & shape of the primary beam
Decrease pt dose
The best type of beam-restricting device is the
Collimator
The purpose of automatic collimation is to ensure that
The field size does not exceed the image receptor size
When collimating significantly
mAs should be increased
Which one of the following will increase as collimation increases?
Contrast
Which of the following is true of positive beam-limiting devices?
They were once required on new radiographic installations
The purpose of a grid in radiography is to
Increase contrast
Grid ratio is defined as the ratio of the
Height of the lead lines to the distance b/w them
Compared w/ parallel grids, focused grids
Allow more transmitted photons to pass to the film
With which one of the following grids would a convergent line be formed if imaginary lines from its grid lines were drawn in space above it?
Crossed focused
Grid cutoff, regardless of the type, is most recognizable radiographically b/c of inadequate
Density
Distance decentering grid cutoff occurs by using an SID that is not
w/i the focal range of the grid
The type of motion most used for moving grids today is
Reciprocating
A grid should be used whenever the anatomic part size exceeds
9cm
The air gap technique requires as increase in ___ compared w/ using a grid
OID
The radiation- & light-sensitive layer of radiographic film is the ____ layer
Emulsion
Crossover is a radiographic problem b/c it decreases
Recorded detail
Spectral sensitivity refers to the color sensitivity of
Radiographic film
During latent image formation, electrons that have been liberated by radiation or light exposure are attracted to the?
Sensitivity specs
Silver halide crystals are found in the ?
Emulsion
Which of the following is the M/C type of film for general radiographic examinations?
Screen, double emulsion
Poor film-screen contact results in a loss of
Recorded detail
The purpose of intensifying screens is to
Decrease patient dose
The M/C phosphor material used in today’s intensifying screens is?
Rare earth elements
The speed of an intensifying screen can be reduced by adding
A reflecting layer
Typically, as screen speed decreases, ______ decreases
Density
The wire mesh test tool, is used to evalute?
Film-screen contrast
Conversion of the latent to the manifest image is accomplished by?
radiographic processing
The sequential order for processing radiographic film is
Developing, fixing, washing, drying
Which of the following solutions are responsible for reducing the exposed silver halide crystals to black metallic silver: 1) ammonium thiosulfate, 2) hydroquinone, or 3) phenidone?
2 & 3 only
The chemical responsible for maintaining the alkalinity of the developing solution is?
Sodium carbonate
The fixing agent used to clear the underdeveloped silver halide crystals is
Ammonium thiosulfate
Staining or fading of the permanent image results when too much ____ remains on the film w/ improper washing
Thiosulfate
Finished radiographs should retain what percentage of their moisture?
10-15%
The type of roller responsible for moving the film from the bottom of the tank upward is a(n) ____ roller
Turnaround
The type of roller responsible for moving the film from one tank to another is a(n) ____ roller
Crossover
Processing chemicals must be replenished to maintain activity & volume when depleted primarily by
Oxidation
Decreasing the developer temperature
Decreases density
Under what environment conditions should radiographic film be stored?
Temp. b/w 50-70 degs & 40-50% relative humidity
Safelight filters are chosen based on the ?
Film sensitivity
The type of silver-recovery unit that uses an electrically charged drum to attract the silver is called a(n) _____ unit?
Electrolytic
A common plus-density artifact caused from bending the film before exposure is
Half-moon marks
What term is defined as a measurement of the amount of light transmitted through the film?
Optical density
What is the diagnostic range of optical densities?
0.25-2.0
An optical density of 1.0 indicates that ____ light was transmitted
10%
Changes in exposure have little effect on density in which of the following regions of the sensitometric curve: 1) toe, 2) shoulder, or 3) straight line?
1 & 2 only
When the exposure technique used produces densities outside the straight-line portion of a sensitometric curve, how is contrast affected?
Decreased
Which type of target interaction is responsible for the majority of x-rays in the diagnostic beam?
Bremsstrahlung interaction
Increasing kVp will result in?
X-rays w/ higher energy
More x-rays
Total filtration in x-ray beam includes?
Inherent filtration
Added filtration
Imaging movement of internal structures is known as?
Fluoroscopy
What image intensifies component converts visible light intensities from the input phosphor to electrons?
Photocathode
The relationship b/w focal spot size & distance results in:
Geometric unsharpness
Increasing the SID will:
Increase recorded detail
Decreasing OID will:
Increase recorded detail
The ability of the imaging system to distinguish b/w two adjacent structures defines:
Resolution
Which of the following has the most detrimental effect on recorded detail of the image?
Motion
The image receptor for computed radiography is composed of:
Barium fluorohalide
Both types of DR flat panel detector digital imaging systems convert x-ray energy into:
Electric charges
The latent image that consists of electrons trapped in the phosphor layer is found w/:
CR
Exposed CR imaging plates should be processed w/i ____ hour(s) to avoid any loss image quality b/c of fading
1
Thin fill transistors (TFTs) are used in DR systems:
temporarily store the electric charge
