RADT 1725 FINAL EXAM
Contact Felt
10
Motor and Drive Chain
10
Screen Film Non-screen Film Special Application Film (mammo, video recording duplication, subtraction, dental radiography)
Types of film:
lp/mm
Unit of resolution is measured using:
Wetting Developing Rinsing in stop bath Fixing Washing Drying
Processing Sequence:
As short as possible
Radiographic exposure times are usually kept:
Detector
Radiographic film is a sensitive radiation ______.
Avoirdupois Oz
There are 14.58 troy oz in 16 ___________, or standard ounces.
OID
To reduce magnification, one should reduce:
Grids
Use of ________ will reduce radiographic contrast?
Laser Film
____ uses the digital electronic signal from an imaging device.
Europium
*Present in small amounts *Activator & responsible for storage property of PSL *Similar to the sensitivity center of film emulsion because without it there would be no latent image
Film Contrast
-The range of densities that the film is capable of recording. -Expressed as the slope of the D log E curve.
...
...
....
....
....
.....
Film
1
Low-Z Front
1
Microswitch
1
Overcoat
1
Blower
11
High-Z back
11
Contact Felt
2
Emulsion
2
Feed Tray
2
Guide Shoe
2
Adhesive Layer
3
Base
3
Crossover Racks
3
Belt and pulley Chain and sprocket Gears
3 Means of Transferring Power to Transport Rack:
Base
4
Master Roller
4
Phosphor
4
Tanks
4
Developing
5
Emulsion
5
Trailing Edge
5
Base
6
Fixing
6
Leading Edge
6
Receiving Bin
9
Emulsion
7
Planetary Roller
7
Washing
7
Drying Chamber
8
Phosphor
8
Base
9
Halving
A 15% decrease in kVp, causes a _______ of exposure to the IR.
Doubling
A 15% increase in kVp, causes a _______ of exposure to the IR
Four
A CR image receptor is responsive to an x-ray beam over how many orders of magnitude?
Solvent
A _______ is a liquid into which various solids and powders can be dissolved.
Troy Oz
A _________ is a unit for measuring precious metals such as silver.
Microswitch
A _________ is what turns on the replenishment system in most processors.
Field-effect Transistor (FET)
A _________ or silicon TFT isolates each pixel element and reacts like a switch to send the electrical charges to the image processor.
30%
A change of ______% in mAs is needed in order to produce a visible change in optical density.
Reduces scatter radiation along two axes
A crossed radiographic grid:
Have to be reduced
A diaphragm is machined to just match image receptor size. If an inexposed border is required on the radiograph, the diaphragm opening will:
Have to be reduced.
A diaphragm is machined to just match image receptor size. If an unexposed border is required on the radiograph, the diaphragm opening will:
After stimulation
A phosphorescent material emits light:
Requires light field/x-ray beam coincidence
A properly designed, light-localizing, variable aperture collimator:
Requires light field/x-ray beam coincidence.
A properly designed, light-localizing, variable-aperture collimator:
Three
A screen-film image receptor is responsibe over how many orders of magnitude?
4-12
A visible change in contrast will not be perceived until kVp is changed by ____-____% which depends on kVp range.
Image magnification
Air-gap technique results in:
Central ray, part, and image receptor
Alignment adjustments involve bringing the ______, _______, and _________ back to their correct relationship.
8 hours
About how much time can pass between exposing a CR cassette and reading a CR cassette before image quality declines?
Halt the development process.
Acetic acid is used to:
2.5 times
Adequate drainage is generally defined as the capacity to handle ________ the maximum outflow of the processor when all drains are open.
Restrict the beam
Adjustable second stage shutter pairs are used to:
Filtration
Affects contrast by changing the average photon energy and decreasing beam intensity.
Quantum Mottle
Affects recorded detail and happens when high speed intensifying screens are used with extremely low mAs
2 to 8
After light has been exposed to light or ioinizing radiation it can be __ to __ more times more sensitive.
Continually mix the processing chemicals. To maintain on contant temperature throughout the processing tank. To aid exposure of the emulsion to the chemicals.
Agitation is necessary to:
Rapid processing Extended processing Daylight processing Dry processing
Alternative processing Methods
The Clean Water Act of 1984
Amends the Clean Water Act of 1977, in that it requires the best available methods be used to remove toxic substances from waste water. Silver is classified as a "priority pollutant" under this law, and the Act prohibits the discharge of these pollutants into surface waters.
Cesium iodide (CsI)
Amorphous Silicon Detectors use thin films of silicon integrated with arrays of photodiodes. These photodiodes are coated with a crystaline ___________ scintillator or a rare-earth scintillator. When these scintillators are struck by x-rays, visible light is emitted proportionate to the incident x-ray energy.
Image contrast
An advantage of CR over screen-film radiography, regardless of the type of examination, is relatively constant:
Film screen contact
An annual wire mesh test is needed to check for:
Just smaller than the image receptor
An aperture diaphragm should allow x-rays to expose an area:
Has higher energy than it should have.
An electron that is described as being metastable:
Fan x-ray beam
An x-ray beam collimated to appear as a cooling fan. Used in CT and SPR
Intesnity
Anode heel effect alters the _______ of radiation, therefore the density.
Short
Anode heel effect is more visible on radiographs that use a _________ SID.
Grid radius
Another name for focal distance:
Potter bucky diaphragm
Another name for reciprocating grids?
Penumbra
Another term for FSB is:
20%
Any film dated before 1974 contains ______ more silver (0.13 to 0.18 troy oz per 14 × 17 inch sheet) than film manufactured since then.
Luminescent; luminescence
Any material that emits light in response to some outside stimulation is called __________ material, or a phosphor and the emitted visible light is called _______.
Divergence of the beam
Any structure which is not positioned at the central ray will be distorted because of the:
Bend Crease Subject it to rough handling
Anyone handling film should be careful not to:
85 million
Approximately _________ troy oz of silver are used in the photographic film consumed in the United States each year.
Silver Recovery Units
Are available for on-site silver recovery and generally require servicing by an outside contractor who is familiar with the equipment and its method of removing silver. -Connected directly to the drain system of the fixer tank to remove silver as used fixer solution passes through the unit. -After the silver is recovered, the used fixer is drained.
Thick
Are thick or thin objects distorted more easily?
Cloudy
As a descriptor of a PSP, the term turbid refers to an appearance that is:
Decreases
As distance increases, radiation intensity and IR exposure _____________.
Increase
As field size increases with film/screen, the density will ____________
More tissue is exposed, more scatter production, increased density, decrease contrast.
As field size increases:
Increases
As field size is increased, scatter radiation:
Decreases
As focal spot decreases, penumbra _______ therefore increasing resolution.
The interspaces width becomes thinner if the width of the grid strip remains constant; The number of grid strips per centimeter increases.
As grid frequency increases:
The number of grid strips per centimeter increases
As grid frequency increases:
Increased
As intensifying screen speed is decreased, resolution is better, but patient dose is _________.
Increases, Increases, Decreased
As kVp _______, scatter radiation ________, and contrast is ________.
Increases
As kVp ________, a wider range of photon energies is produced, which in return increases the ability of the photons to penetrate the body tissues. This ultimately leads to wider range of exposures which will lower contrast.
The number of absorbed x-rays will decrease
As kVp increases from 70 to 90, if all other factors remain constant:
Decreases
As kVp increases, contrast _______.
Increase because of more Compton interaction.
As kVp increases, scatter radiation production will:
increase because of less Compton interaction.
As kVp increases, scatter radiation production will:
There will be a higher proportion of scatter radiation
As kVp is increased from 70 to 80 reaching the IR:
There will be a higher proportion of scatter radiation.
As kVp is increased from 70 to 80 reaching the IR:
High
As long as the kVp is adequate to penetrate the body part being examined, it will produce ______ subject contrast area.
Increases
As mAs increases, x-ray exposure increases proportionally and film density also _________.
Decreases
As relative speed increases, the amount of exposure required to maintain the same density/IR exposure _______.
Increases
As the actual focal spot increases, the effective focal spot ________.
A.
As the grid ratio increases, there is also an increase in which of the following? A. Contrast improvement factor B. Intensification factor C. Spatial resolution D. System speed E. Width of interspace material
Contrast improvement factor.
As the grid ratio increases, there is also an increase in:
Absorbed Scattered Transmitted
As the primary x-ray beam interacts with the anatomic part, photons will be:
Fog increases
As the time of film development is increased beyond the manufacturer's recommendations:
Increases; Increases
As x-ray energy _________, the relative number of x-rays that undergo compton scattering ______________.
Increases.
As x-ray tube potential is increased, the IF _______.
Transmitted through the bod with interaction
At high kVp, most x-rays are:
Transmitted through the body with interaction
At high kVp, most x-rays are:
Less photon interaction, which results in more x-ray transmission.
At higher kilovoltages, more or less photon interactions?
More photon interactions which results in more or less x ray transmission
At lower kilovoltages, are there more or less photon interaction?
Metastable
Atoms of barium fluorohalide have numerous Compton & photoelectric x ray interactions which occur with the outer shell electrons sending them into an excited, ___________ state. When these electrons return to ground state, visible light is emitted.
Positive beam limitation
PBL stands for:
Positive beam limitation:
PBL stands for:
Photoiodide
PD
With lead lining to prevent backscatter radiation from reaching IP
Back side of IR plate is made with? And Why?
Water Pollution Control Act of 1972
Bans the placement of toxic substances in public waterways and sewer systems.
The optical density of the base
Base density refers to:
Exposure Maintenance Formula
Based on the inverse square law but is reversed to a direct square law because mAs must increase when distance increases.
Inversely
Beam Restriction is ________ related to density/IR exposure. Increased beam restriction decreases density.
Increases
Beam restriction will reduce the number of photons available. By reducing the photons available, it reduces scatter, and _______ contrast.
Intensification Factor
Because screens are used to reduce patient does, one characteristic is the magnitude of dose reduction. This property is called the __________ and is a measure of the speed of the screen.
Intensification Factor (IF)
Because screens are used to reduce patient dose, one characteristic is the magnitude of dose reduction. This property is called the ____________ and is a measure of the speed of the screen.
30 years.
Before the digital revolution in diagnostic imaging, the recovery of silver from film and film processing has been a standard practice in most hospitals and medical centers for at least ____________.
Patient Communication
Best way to reduce motion:
Increase; Decrease
Bone has a higher atomic number than tissue so therefore it will have an _____ in subject contrast when comparing the two tissues. When there is little differences in tissues the subject contrast will _______.
kVp
Both quantity and quality vary significantly with changes in _____.
Monitor control function
Brightness is a ___________ which can change the lightness and darkness of the image on a display monitor but it is not related to IR exposure.
An unexposed border should be visible on all four sides of the radiograph
If a fixed-aperture, rectangular, beam restricting device is used:
An unexposed border should be visible on all four sides of the radiographh.
If a fixed-aperture, rectangular, beam-restricting device is used:
IP (Imaging Plates)
CR cassettes are referred to as:
A dark room
CR cassettes eliminate the need for:
10,000 shades of grey
CR imaging allows for the display of about:
Recording phosphor
CR replaces film with ______________.
IR (Image Receptor)
CR uses the _____ to store electrons in high energy traps
Sequestering Agents
Components of the Developer: Developer may contain metal impurities and soluble salts which can accelerate the oxidation of hydroquinone, rendering the developer unstable. Chelates are introduced to form stable complexes with the metallic ions and salts.
mAs
Changing kVp alters the intensity of the beam when ______ and other factor remain the same.
1. The chemicals used are hazardous and require special precautions. 2. Toxic fumes such as chlorine gas and hydrogen are created by the chemical reaction. 3. A large drum or vat with adequate space is required. 4. The process is labor intensive, which reduces the profit margin.
Chemical Precipitation Disadvantages
Gelatin
Clear, so it transmits light and is sufficiently porous for processing chemicals to penetrate crystals of silver halide.
Motorized shutters
Collimator units manufactured between 1974 and 1994 have ________________.
Directly proportional
Compensations for changes in relative speed can be made by adjusting mAs because the exposure is ____________ to mAs.
It has enough energy to remove an inner shell electron
Complete absorption of the incoming x-ray occurs when:
Transport system Temperature Control system Circulation system Replenishment system Dryer system
Components of the Automatic Processor
Activator
Components of the Developer: -Composed of alkali compounds such as sodium carbonate and sodium hydroxide -These buffering agents enhance the action of the developing agent by controlling the concentration of hydrogen ions: pH -Sodium hydroxide is the strongest alkali and commonly called lye (very corrosive and can burn skin)
Preservative
Components of the Developer: Controls oxidation of the developing agent by air. Air is introduced into the chemistry when it is mixed, handled and stored, such oxidation is called aeiral oxidation. (By controlling the aerial oxidation, the preservative helps maintain the proper development rate). Mixed chemicals only last a couple weeks therefore replenishment tanks require close fitting lids to control aerial oxidation. Hydroquinone is sensitive to aerial oxidation.
Hardener
Components of the Developer: Gluteraldehyde is the chemical used. If emulsion swells too much or becomes to soft the film will not be transported properly through the system so a hardener is needed. Promotes archival quality.
Restrainer
Components of the Developer: Restrict the action of the developing agent to only those silver halide crystals that have been irradiated. Potassium bromide and potassium iodide are added to the developer as restrainers. Anti fog agent; Protects unexposed crystals from chemical "attack"
Helps swell the gelatin Produces alkalinty Controls pH
Components of the Developer: What is the function of the Activator?
Controls emulsion swelling Enhances archival quality
Components of the Developer: What is the function of the Hardener?
Removes metallic imurities Stabilized developing agent
Components of the Developer: What is the function of the Sequestering Agents?
Sodium sulfate
Components of the Developer: What is the usual preservative?
Fixing Agent
Components of the Fixer: Clearing agent, hypo and thiosulfate are used in reference to fixing agent. Removes unexposed or underdeveloped silver halide crystals from the emulsion. Ammonium thiosulfate is the most common used.
Activator
Components of the Fixer: Contains acetic acid Neutralizes the pH of the emulsion Stops developer action
Sequestering Agent
Components of the Fixer: In the same way that metallic ions must be sequestered in the developer, so they must be in the fixer. Boric acids and salts are used for sequestering.
Hardener
Components of the Fixer: Purpose is to ensure that the film is transported properly through the wash and dry section and that rapid and complete drying occurs. Chemicals commonly used are potassium alum, aluminum chloride, and chromium alum. Stiffens and shrinks the emulsion.
Preservative
Components of the Fixer: Serves the same purpose as the preservative in the developer. Sodium sulfite is used and it is needed to maintain the chemical balance.
Buffer
Components of the Fixer: The pH of the fixer must remain constant. Acetate is normally used.
Solvent
Components of the Fixer: Water is used to dissolve other components.
Image buffer
Computed Radiography: -Usually a hard disc -Place where the completed image can be stored temporarily until it transferred to a workstation for interpretation or to an archival computer
-CR plate is inserted into the CR reader -IP is removed and is fitted to a precision drive mechanism -Drive mechnism moves the IP at a steady pace along the long axis of the IP -Small fluctuation in velocity can result in banding artifacts -While the IP is being transported in the slow scan direction, a deflection device such as a rotating polygon or an oscillating mirror deflects the laser beam back and forth across the IP. This is the fast scan mode. -Another method is for the cassette to be placed in the reader vertically with the IP withdrawn downward. As this occurs, the cassette is scanned by a horizontal laser. -The IP barely leaves the cassette, so it is not subject to roller damage. Furthermore, the scan is nearly always located at right angles to the direction of any grid lines; in this way, aliasing artifacts are reduced.
Computed Radiography: Mechanical Features:
-Source of stimulating light It spreads as it travels to the rotating or oscillating reflector. -This light beam is focused onto the reflector by a lens system that keeps the beam diameter small (<100 µm). -The laser beam changes in size and shape as it is deflected across the IP Flashlight test (Demonstrate in classroom) **Now move the beam along the wall slowly but with constant velocity, and what do you see? The beam becomes distorted, moves faster, and is less intense. These types of changes in a CR reader are corrected with the use of beam-shaping optics.
Computed Radiography: Optical Features: The laser
Monochromatic; Polychromatic
Computed Radiography: The The laser light used to stimulate the PSP is _____________. Resultant light emitted is _____________.
Photodetector
Computed Radiography: The output of the ____________ is a time-varying analog signal that is transmitted to a computer system that has multiple functions
Ghosting would appear on the next use of the IP
Computed Radiography: What happens if latent image is remained on IP?
-Reduces backscatter -Improves the contrast resolution of the image receptor
Computed Radiography: Why does an IP have lead backing?
HeNe
Computed Radiography: __________gas laser used to be the stimulating source of choice, but this has been largely replaced by a solid state laser.
Storage phosphor screens
Computed Radiography: * Appear white because of small PSP particles scatter light excessively * Turbid is the term used to describe such scattering *Are mechanically stable, electrostatically protected, and fashioned to optimize the intensity of stimulated light
Lower patient radiation dose
Computed Radiography: CR is a faster image receptor compared with a 400-speed screen-film system; therefore, _______________ should be possible with CR.
-Mechanical -Optical -Computer modules
Computed Radiography: CR represents a union of:
-The laser -Beam-shaping optics -Light-collecting optics -Optical filters -A photodetector
Computed Radiography: Components of the optical subsystem include:
Storage phosphor screens
Computed Radiography: Latent image will occur in form of metastable electrons, these screens are called _____________.
Photomultiplier tube
PMT
Fluorescent lamps
Computed Radiography: Residual latent image is removed by flooding phosphor with very intense white light from a bank of specifically designed _________________. PSP's are sensitive so images can be fogged by background radiation
Linear filaments
Computed Radiography: Some SPS's incorporate phosphors grown as _____________ that increases the absorption of x-rays and limit the spread of stimulated emission
Occurs when the axis of the cone, tube, and image receptor are not aligned
Cone cutting:
Flat Panel Detectors
Consists of a photoconductor such as amorphous selenium, which converts x-ray photons directly into electrical signals. This category also includes silicon and CCD detectors.
Smudge
Consists of dark areas where excessive amounts of light have exposed the film and is usually caused by rough handling in the film processing area.
Turnaround Assembly
Consists of: Master roller- Pushes the leading edge of film against the guide shoes Planetary rollers & guide shoes- force the edge of film around master roller until it is positioned upward. Located at the bottom of the transport rack assembly.
Increase
Contrast media will __________ subject contrast by introducing greater differences in atomic number variations than those that exist naturally.
Magnification Size Distortion
Controlled by positioning the body part and the tube to maximize SID while minimizing OID.
mAs & SID
Controlling factors of Optical density
Reader unit & workstation
Conventional processor is replaced with ________ & _________.
c. Both a & b.
Preservative is found in __________. a. The developer soulution. b. The fixing solution c. Both a & b
Luminescence
Similar to characteristic x-ray emission, however it involves outer-shell electrons
Periodic checks of x-ray beam and light field coincidence are necessary.
In a light-localizing, variable-aperturee collimator:
Increase
The economic downturn of 2008 has lead to a dramatic _______ in the price of silver.
Subject Contrast (Digital)
The magnitude of the signal difference in the remnant beam.
Silver Bromide
In a typical emulsion, 98% of the silver halide is __________ and the remainder is silver iodide, which have high atomic numbers.
Intensifying Screens
Create higher contrast; Contrast is lower for film exposed to x-rays than those exposed to light.
Remove more scatter than linear grids - more lead & more lead strips in oriented in 2 directions
Cross hatched therefore contain more lead, does this remove more or less scattered photons than linear grids?
Dye
Crossover is reduced by adding a ____ to the base (called a crossover control layer.)
Silver Bromide & Silver Iodide
Crystals in the film emulsion consists of:
65° to 75° F
Darkroom temperature should be maintained in a range of:
Darkroom walls should be painted in pastels and light colors to increase the reflectance of the light emitted from the safelight.
Darkroom walls should be painted in what colors? And why these colors?
Decreasing
Decreasing beam intensity will decrease densities/IR exposure therefore _________ contrast.
Photon interactions will increase
Decreasing the energy of the x-ray beam will do what to the number of photon interactions?
Decrease it
Decreasing the energy of the x-ray beam will do what to transmission?
Process where the x-ray beam is absorbed in the tissue and some passes through (transmitted)
Define differential absorption
A decrease in the number of transmitted photons that reach the IR because of some misalignment of the grid.
Define grid cutoff:
The number of lead lines per unit length in inches, centimeters, or both.
Define grid frequency.
Distance between the grid and the convergent line or point.
Define grid radius/focal distance
The ratio of the height of the lead strips to the distance between them
Define grid ratio.
Distortion
Defined as a misrepresentation of the size and/or shape of the anatomical part being imaged. Can be classified as either size or shape.
Density/IR Exposure
Defined as the overall blackening that is the result of black metallic silver deposited in the emulsion of the film. It is the viewable result of a films response to exposure.
Scale of Contrast
Defined by the number of useful visible densities or shades of gray.
45%
Depending on the angle of the anode, this effect can cause an IR exposure variation of up to 45% between anode & cathode ends of the image.
Is an artifact that can occur when a stationary grid is used during CR imaging
Describe Moire effect
Digital Radiography (DR)
Describes images recorded on an electronically readable device. Includes both computed radiography and direct and indirect methods of digital image capture.
Added filtration
Describes the filtration that is added to the port of the x-ray tube.
Contrast (Digital)
Determined primarily by the processing algorithm (mathematical codes used by the software to provide the desired image appearance). The default algorithm determines the initial processing codes applied to the image data.
Complementary metal oxide silicon (CMOS)
Developed by NASA, _____________ systems use specialized pixel sensors that, when struck with x-ray photons, converts the x-rays into light photons and store them in capacitors.
Maximizing; Minimizing
Diagnostic quality is achieved by __________ the amount of recorded detail and _________ the amount of image distortion.
DMIST
Digital Mammography Imaging study Trial; An ACRIN trial to see if digital mammography is equal to screen-film mammography.
-Matrix size -Pixel size -Grayscale bit depth
Digital imaging recorded detail is determined primarily by:
Advantages: -No capital outlay for equipment is required Disadvantages: -Considerable handling or storage -Fee for pick up and hauling of solution
Direct Sale of Used Fixer
Umbra
Distinctly sharp area of a shadow or the region or complete shadow.
Proper patient positioning
Distortion can be corrected by:
Directly
Distortion is ________ related to positioning.
Magnification
Distortion of an x-ray image results from unequal:
No
Does scatter radiation provide any diagnostic information about the area being imaged?
Lose
Does the x-ray beam passing through the anatomic tissue lose or gain energy?
More stimulable light emission
Doping of a PSP with europoium results in:
WWI
During _____, glass was not readily available but applications of x-ray was rapidly increasing.
1965
Eastman Kodak introduced 90 second automatic processing in ______.
Emitted light intensity
Europium is an activator in the PSP, an activator is responsible for:
Rack Assembly
Except for the entering rollers at the feed tray, most rollers are positioned on a ___________. These racks are removable and provide for a convenient maintenance and efficient cleaning of the processor.
Decreases
Excessive or inadequate density/IR exposure ________ contrast.
Inverse Square Law
Expresses the change in intensity when distance changes; Affects exposure in inverse proportion to the square of the distance.
Reducing OID
FSB can be reduced by:
C.
Function of fixer is to: A. Remove unexposed silver halide crystals B. Remove undeveloped silver halide crystals C. Both A & B D. None of the above
Heat, humidity and static electricity
Film can be affected by:
-Intensifying screens -Film density -The D log E curve -Processing
Film contrast is dependent on 4 factors:
Loss of speed and contrast Incrase in fog
Film must be used before the expiration date due to aging which results in:
Pete
Film of this nature is sometimes referred to as ______. A price per pound is negotiated for the film and the money paid to the facility.
60%
Film should be storage under conditions of elevated humidity (over ______).
Warping Sticking to one another Suffer from pressure artifacts
Film should be stored on its edge rather than laying them flat. Storing film this way reduces the likely hood of film:
Scintillators
Film/Screen uses __________ to transfer information.
the off-focus radiation
First stage shutters protrude into the tube housing to control:
Line Focus Principle
Focal spot size is controlled by the __________.
Angled or canted
Focused grids have lead lines which are:
Background radiation
Fog will appear on the CR cassettes with exposure to:
X-ray tube current & the time that the x-ray tube is energized
For any radiographic examination, the number of x-rays that reach the image receptor is directly related to both the:
Silver Refiner
For images For images that are not of diagnostic quality (and therefore not kept for the patient's files), the sheets of film can be stored in a bin and then sold to a ____________.
Wetting
For the chemicals to penetrate the emulsion, the radiograph must be treated by a ______ agent.
Base
Foundation of radiographic film.
-Made of radiolucent material that does not absorb primary x-rays -This allows the max # of x-rays to reach IP
Front of cassette is made with? And why?
Atomic numbers
Gelatin and base have low ________.
Spatial Resolution
Generally, conditions that increase the IF reduce ____________.
D
Green film is: A. Unprocessed film B. Expired film C. Accidently exposed film D. All of the above
Contains a permanently mounted grid and allows the IR to slide in behind it
Grid Cap:
An IR that has a grid permanently mounted to its front surface
Grid Cassette:
The type of interspace material used Grid frequency Grid ratio Grid size Information about the range of SIDs that can be used with the grid
Grid Information includes:
Height, Thickness Space between them
Grid contain lead strips which have a precise:
High ratio grids
Grid cutoff is more pronounced with:
Photoelectrons & X-rays after photoelectric interaction
Grids are principally effective in attenuating:
Increase mAs
Grids will reduce the number of x-rays reaching the IR, what technical factor must be increased to compensate for less x-rays hitting IR?
Direct Exposure Film
Has a high subject contrast and presents low radiation risk.
Metastable
Having a state of apparent equilibrium although capable of changing to a more stable state
Noise
Higher conversion efficiency results in increased _______.
Remove/Clean up more scatter Increase radiographic contrast
Higher ratio grids can improve two things:
Inversely proportional
How are latitude and contrast related?
They run at right angles to one another
How are lead lines situated on a cross or cross hatched grid?
Use of a higher grid frequency or a moving grid with CR digital imaging eliminates this type of grid error.
How can the technologist avoid the Moire effect?
Beam-shaping optics
How does the CR reader maintain the laser beam as a circle?
By intense white light
How is the IP erased in the reader?
Anatomic part should be more than 10 cm
How large must the anatomic part be in order to use a grid?
40 seconds
How long can an xray be exposed under the safelight before experiencing fog?
1 hour
How long did manual processing of radiographs take?
Two
How many kinds of x-rays are responsible for optical density?
Two: Linear and Cross or Cross Hatched
How many types are there?
Parallel (nonfocus) Focused
How many types of grid focus are there? Name them
Up to 10,000 times
How often can PSP be reused?
should be cleaned weekly with an antistatic, non-abrasive cleaner,
How often should viewboxes be cleaned?
Film must be stored in an upright position to avoid pressure marks.
How should film be stored and why?
150-300 um
How thick is radiographic film base?
Imaging Plate
IP
8
IP should be processed within how many hours?
Cathode
IR exposure is always greater on the _________ end.
Green
If _____ emitting screens are used they should be matched with a film that is sensitive to green light. Such film is orthochromatic and is called green sensitive film.
Patient does will decrease.
If a constant optical density is maintained while kVp is increased:
Patient dose will decrease
If a constant optical density is maintained while kVp is increased:
Density
If a film is used without spectral matching, the result is a reduction in:
Increase
If field size is increased, patient dose will ________
Increase image contrast
If grids are used properly, it can do what to contrast?
Replenished
If neither the developer nor the fixer is replenished each quickly loses chemical balance and the level of solution in each tank drops, resulting in short contact times of the film with the chemicals
Image contrast would be very low.
If only scatter radiation reached the image receptor:
Exposure Time
If patient is unable to cooperate, the best method is a reduction in ___________ with corresponding increase in mA to maintain sufficient mAs and film density/IR exposure.
Increases with increasing grid ratio
If radiographic grids are used and the technique is compensated, patient exposure:
Decreased.
If replenishment rates are decreased, radiographic contrast is _________.
Increased.
If replenishment rates are increased, radiographic contrast is slightly ______.
The top or bottom of the image.
If the beam is not centered to the film, collimator cut-off will occur on:
Yes, it allows more transmitted photons to reach IR
If the focused grids have angled lead lines which attempt to match the angle of the primary beam, does it allow more transmitted photons to reach IR?
Make the grid thicker
If the interspace dimension is constant, increasing the grid ratio will:
Phosphorescence.
If the phosphor continues to emit light after stimulation, the process is called __________.
Side to side collimator cut-off
If the tube is not centered to the Bucky or the film is not pushed into the Bucky, what type of cut-off will occur?
Fluorescence
If visible light is emitted only while the phosphor is stimulated, the process is called _________.
Subject contrast
Image contrast is the product of image receptor contrast:
E.
Image forming x-rays consist of which of the following type that emerge from the patient in the direction of the image receptor? A. Absorbed x-rays B. Backscattered x-rays C. Emitted x-rays D. Intercepted x-rays E. Transmitted x-rays
Shorter OID
Image magnification can be reduced with the use of:
OID
Image magnification increases with increasing:
Speckled Background
Image noise appears on a radiograph as a ___________. It occurs most often when fast screens and high-kVp techniques are used. Noise reduces image contrast.
Transmitted without interaction & scattered through Compton interaction.
Imaging forming x-rays are those that are:
Penumbra
Imperfect, unsharp shadow surrounding the umbra. Also known as edge gradient.
1967
In ________ the federal government lifted previous regulations governing the sale of silver, which escalated the price and therefore increased the demand on worldwide markets.
Direct conversion
In ____________, x-ray photons are absorbed by the coating material and immediately converted into an electrical signal.
8:1
In a grid that has lead strips 0.5 mm apart and 4 mm high, the grid ratio is:
Periodic checks of x-ray beam and ligh field coincidence are necessary.
In a light-localizing, variable- aperture collimator:
Circulation System
In automatic processing, the ______________ continuously pumps the developer and fixer, therefore maintaining constant agitation within each tank.
Developer
In automatic processing, the wetting agent is in the _________.
kVp is increased
In general, as the thickness of the anatomy for which radiographs are made increases:
D.
In general, the selectivity of a grid depends principally on which of the following? A. Contrast improvement factor B. Focal length C. Grid Frequency D. Grid mass E. Grid radius
A.
In general, which of the following has the greatest contrast improvement factor? A. Crossed grids B. Focused grids C. Moving grids D. Parallel grids E. Zero grids
E.
In the design of a radiographic grid, which of the following would be true? A. The added filtration must be aluminum B. The grid strips are radiolucent C. The grid strips are radiotransparent D. The interspace material is radiolucent E. The interspace material is radiopaque.
The interspace material is radiopaque
In the design of a radiographic grid:
B.
In the design of radiographic technique, the most common practice is to use which of the following? A. A crossed grid B. A focused moving grid C. A focused stationary grid D. A parallel moving grid E. A parallel stationary grid
Photoelectric effect
In the diagnostic range, this x-ray interaction is known as:
Safelights
Incandescent lamps with a color filter; They provide enough light to illuminate the darkroom while ensuring the film remains unexposed.
Decrease
Increased Collimation will do what to scatter radiation?
Decrease
Increased collimation will do what to patient dose?
Increase
Increased collimation will do what to quantum noise in digital radiography?
Decrease
Increased collimation will do what to radiographic density - film/screen?
Decrease
Increased filtration will ________ contrast.
Decrease
Increased filtration will ____________ density/IR exposure.
More Compton interactions. (less photoelectric interactions, more scatter produced)
Increased kVp equals more:
SID
Increasing ______ is effective in reducing FSB
Decrease
Increasing film developer time, temperature or replenishment rate will increase the chemical fog on the film. These changes ________ the slop of the D log E curve therefore decreasing contrast.
Decrease
Increasing fog will ______ contrast.
Increasing grid frequency, decreases lead content because the width interspaces and/or thickness of lead strips have been decreased, therefore decreasing scatter.
Increasing grid ratio, increases lead content, therefore increasing scatter absorption. So what happens when you increase grid frequency?
Increases
Increasing kVp _________ scatter.
Increases
Increasing kVp __________ fog
Decreasing
Increasing photon energy will increase Compton interactions, therefore ______ contrast.
C
Justifications of silver recovery include: 1. Compliance with federal law 2. Monetary return back into the department 3. Dwindling worldwide supply of silver 4. Monetary return back to the individual turning in silver A. 1 & 3 B. 1 & 2 C. 1, 2, & 3 D. All of the above
As short as possible
Keep exposure time:
Amorphos
Lacking form. Not crystalline in form, but rather like a paint of crystals.
Greater
Larger focal spot utilize a _______ incident electron stream than small focal spots.
Modulation
Laser Film: The intensity of the laser beam is varied in direction proportion to the strength of the image signal. This process is called laser beam _________.
Exposure
Latent image formation occurs during film _______.
One; It allows angulation of the x-ray tube along the length of the lead lines
Linear grids run in how many directions? Why is this the most popular?
Upside down focused Off level Off center Off focus
List errors which can occur with grid use:
Stationary Nonmoving -wafer -slip on grid Grid cap
List the types of grids:
Wider latitude or margin of error in producing an acceptable radiograph
Low contrast imaging procedures have:
Increase
Low-energy photons serve only to ___________ patient dose and do not contribute to image formation
SID or OID
Magnification is controlled by SID or OID
Focal Spot
Major controller of image resolution because it controls penumbra.
10%
Many studies have demonstrated that about ______ of the purchase of film can be recovered through proper silver reclamation procedures.
Europium
Materials such as barium fluorohalide with ______ emit some light.
Greater
Materials with a higher atomic number, absorb greater percentage of x-ray beam because of the _______ number of electrons, which enables more interactions to occur.
Displacement Method
Metallic Replacement is sometimes called the _____________ and is the simplest and least expensive method for a diagnostic imaging department.
One that uses steel wool One that uses a silver-extraction filter.
Metallic replacement silver-recovery units can be one of two types:
Processing supplies, materials, and equipment
Money obtained from silver recovery procedures can be returned to the diagnostic imaging department to help offset the cost of:
Barium Fluorohalide with Europium.
Most IP phosphors are made with?
Round or Rectangular
Most cones produce what type of image?
Electrolytic Method
Most efficient method, but the units needed for this process are also more expensive than metallic replacement units. -These units have an electrically charged drum or disk that attracts silver. The silver plates onto the drum or disk and can be removed when a substantial amount of silver has been collected.
CR reader Computer work station Computer system with monitors for radiologists to view images Printer Computer server to store images
Name all components of CR equipment:
Aperture diaphragm Cones & cylinders Collimators
Name three principle types of beam restricting devices:
Direct Exposure Film
Not commonly used today; Possesses the highest resolution possible. Disadvantage: uses 20 to 100 times the mAs of a film/screen exposure.
Fixer Circulation
Not normally necessary because the filter hardens shrinks the gelatin so that the rollers are not coated.
Transport System
Not only transports film, but it also controls processing by controlling the time the film is immersed in each wet chemical. Timing for each step in processing is governed by careful control of the rate of film movement through each stage.
Penumbral overalp
Objects smaller than the focal spot itself cannot be imaged due to __________. The entire image is composed of overlapping penumbra with no umbra to define the edges.
Cone cutting:
Occurs when the axis of the cone, tube and image receptor are not aligned.
Crossover
Occurs when x-rays cross the base to expose the emulsion on the opposite side of the radiographic intensifying screen.
Increases patient dose
Off-focus radiation
Increases patient dose.
Off-focus radiation:
Fixing
Once development is complete, the film must be treated so that the image will not fade but will remain permanently- this stage of processing is called ______.
mAs
One factor that does not affect the percentage of scatter radiation that reaches the image is:
Fixer
One function of the _______ is to remove the unexposed and undeveloped silver halide crystals from the film.
Directly
Optical density increases _______ with mAs.
Glass Plate
Originally the film base was a _______.
Green
Orthochromtic film is sensitive to _______ light.
Decreased
Overall energy of primary beam is __________ as it passes through the anatomic part.
Photostimulable phosphor
PSL
Exposed to light
PSP emit light when:
Can be fogged by background radiation.
PSP image receptors
Metastable states are produced
PSP image receptors are effective because:
Fluoroscopy & Mobile imaging
Parallel grids are used primarily in what two areas of imaging.
Parallel
Parallel grids have lead lines that run ________ to one another.
D.
Patient motion during exposure will result in which of the following? A. A handling artifact B. A processing artifact C. A storage artifact D. An exposure artifact E. An imaging system artifact
Decreases
Patient radiation dose ___________ with increasing grid ratio.
System noise
Patient radiation dose reduction in CR is limited by:
Attenuation or absorption unsharpness
Penumbra is increased by another phenomenon-- ____________________. Because of the divergence of the x-ray beam, only an object of trapezoidal shape would have a perfectly sharp edge.
Low density = white or clear areas
Photoelectric effect create low or high density areas on an image?
Drive Subsystem
Power of transport system is provided by a fractional horsepower drive motor. The shaft of the drive motor is usually reduced to 10 to 20 rpm through a gear reduction assembly. A chain, pulley or gear assembly transfers power to the transport rack and drives the rollers.
Foreshortening
Projects the object so it appears shorter than it really is. Occurs only when the part is improperly aligned.
Elongation
Projects the object so it appears to be longer than it really is; Occurs when the tube or the image receptor is improperly aligned.
Proper collimation reduces scatter radiation that improves contrast
Proper collimation does what to scatter radiation & contrast?
Right angles
Proper positioning is achieved when the central ray is at _________ to the anatomical part and the image receptor, this means the part and image receptor must be parallel.
Developer
Provides electrons to the sensitivity center of the crystal to change silver ions to silver.
To minimize motion blur
Purpose of short exposure time:
Clean up scatter Increase radiographic contrast
Purpose of using grids (2)
Different shades of gray on the image receptor
Radiation exiting the patient will do at varying degrees causing what?
Overexposed
Radiograph which is too dark and has a high optical density.
Underexposed
Radiograph which is too light and has a low optical density.
Spectral Response
Radiographers must be careful to use film whose sensitivity to various colors of light-- it's ______ is properly matched to the spectrum of light emitted by the screen.
Phosphor
Radiographic Intensifying Screen: Active layer. Emits light during stimulation of x-rays Vary in thickness from 50 to 300 um. The action can be seen by viewing an opened cassette in a darkened room through the protective window of the control booth. The radiographic intensifying screen glows brightly when exposed to x-rays.
Protective coating Phosphor Reflective layer Base
Radiographic Intensifying Screens have 4 distinct layers.
Base
Radiographic Intensifying Screens: Layer furthest from the film. Approximately 1mm thick. Serves as support for active phosphor layer.
Reflective Layer
Radiographic Intensifying Screens: Located between the phosphor and base. Approximately 25 um thick. Made of magnesium oxide or titanium dioxide. Intercepts light headed in other directions and redirects it to the film. Enhances the efficiency of the radiographic intensifying screen, nearly doubling the number of light photons that reach the film
Scatter radiation
Radiographic cones and cylinders are used principally to reduce:
Photoelectric effect; Photoelectric
Radiographic image contrast occurs due to the ____________. High contrast is directly related to the number of __________ interactions.
Protective Coating
Radiographic intensifying Screens: This layer is the closest to the film. 10 to 20 um thick. Applied to the face of the screen to make the screen resistant to the abrasion and damage caused by handling. Helps eliminate buildup of static electricity. Transparent to light.
Aluminum or plastic fibers
Radiolucent interspace material separates lead lines. What is the interspace material made of?
4:1 to 16:1
Range of Grid Ratios:
Dynamic Range
Range of brightness as displayed on a monitor.
Subject Contrast
Range of differences in the intensity of the x-ray beam after it has been attenuated by the subject. Dependent on kVp and irradiated material.
Moves, therefore blurring the grid lines
Reciprocating does what during the x-ray exposure?
Increases
Reduced magnification size distortion _________ the resolution of recorded detail.
Spatial Resolution
Refers to how small an object can be imaged.
Tissue Density
Refers to how tightly the atoms of a given substance are packed together.
Contrast Resolution
Refers to the ability to image similar tissues, such as silver and pancreas or gray matter and white matter.
Recorded Detail
Refers to the distinctness or sharpness of the structural lines that makeup the recorded image.
Inherent filtration
Refers to the filtration that is permanently in the path of the x-ray beam.
Spatial Resolution
Refers to the smallest object that can be detected in an image.
Exit the patient.
Remnant x-ras are those that:
Exit the patient
Remnant x-rays are those that:
Microswitch
Replenishment of fixer and development are controlled by the:
Developer Circulation.
Requires a filter that traps particles as small as 100um to rap flecks of gelatin that are dislodged from the emulsion. The particles has less chance of becoming attached to rollers, where they can produce artifacts.
Resources Conservation/Hazardous Waste Act of 1976
Requires available devices be used to remove toxic substances from waste water.
Radiographic intensifying Screens
Resemble flexible sheets of plastic or cardboard.
Decreases
Resolution is improved when OID ________.
Increases
Resolution is improved when SID _________.
Master Rollers
Roller Assembly: Also known as solar rollers Diameter of 3 inches is used when the film makes a turn in the processor A number of planetary roller and metal or plastic guide shoes are positioned around this roller.
Transport Rollers
Roller Subassembly: Diameter of one inch, convey film along its path. Positioned opposite from one another in pairs or are offset from one another
0.5 to 0.8
Roughly __________ troy oz of silver is in each gallon of used fixer. In small-volume facilities (<10 gal/wk), metallic replacement or electrolytic units may not be practical. In this case, used fixer can be collected in storage drums and sold to a refiner who reclaims the silver from the solution.
Decrease; Increase
SID alters intensity of the beam reaching the image receptor according to inverse square law; Greater distances _______ density/IR exposure, less distances ________ it.
Storage phosphur
SP
SPR
Scanned projection radiography. The use of a fan x-ray beam and linear detector array to form a projection radiograph.
Increases
Scatter radiation increases as the field size ___________.
Contrast
Scatter radiation reduces radiographic quality by changing:
Compton effect
Scattering results from diagnostic x-ray interaction with matter known as
Image receptor.
Screen Film and CR both use an _________ which is x-ray sensitive which is encased in a protective case. *Screen film-Film *CR- Image Plate
1. size of the phosphors. 2. thickness of the phosphors. 3. composition of the phosphors. 4. concentration of the phosphors.
Screen characteristics are determined by the:
30 shades of grey
Screen-film radiography allows for the display of about:
Contrast Speed Spectral matching Anticrossover/Antihalation Dyes Requirement for a safelight
Several Characteristics to consider when selecting screen film:
Alignment
Shape distortion can be caused or avoided by __________ of the central ray with the anatomical part.
100mg/m
Silver may accumulate at a rate of ___________ of film that is processed.
Metallic Replacement Electrolytic Method
Silver-Recovery units work by one of two methods:
Contrast Speed Crossover Spectral matching Reciprocity Safelights
Six characterisitcs when selecting screen film:
a. Preservative
Sodium Sulfite is found both in the developer and the fixer. What is its purpose? a. Preservative b. Hardener c. Sequestering agent d. None of the above
Charge-coupled device
Solid state system that converts light into an electrical signal with very high spatial resolution
Screen blur decreases, motion blur decreases and geometric blur decreases
Spatial resolution improves as:
Laser beam diameter
Spatial resolution in CR is principally determined:
Focal-spot size
Spatial resolution is principally affected by:
Digital image
Special electronics convert the light into an electric signal to produce what?
Spatial frequency
Specification of object size and inverse size.
Static Artifacts
Storing film in very low humidity conditions can cause:
10%
Studies have demonstrated that approximately _____% of the purchase of film can be recovered through proper silver recovery procedures.
Decreased
Subject contrast is _________ when using high kVp because more uniform penetration occurs between thick and thin parts.
Scintillation phosphor
Such as NaI, CsI, and other similarly behaving crystals that emit light in response to an x-ray interaction.
Decreases
The absolute number of Compton interactions _____________ with increasing energies but the number of photoelectric.
Hold halide crystals
The main purpose of the gelatin emulsion in radiographic film is to:
Scale of Contrast (Digital)
Synonymous to "gray scale" and is linked to the bit depth of the system. Gray scale is used instead of contrast when referring to digital images.
The Resource Conservation and Recovery Act (RCRA) or 1987
The Act limits liquid waste to a level of no more than 5 mg/L or parts per million (ppm) of silver. Used fixer and wash water may exceed this amount. Special permits are required to dump more than 27 gallons of waste per month into public sewers. For private septic systems, a permit from the National Pollutant Discharge Elimination System (NPDES) and/or the EPA is required. Shipping manifests are required to ship material such as silver recovery cartridges, scrap film, silver flake, or silver-laden fixer.
Blower Ventilation ducts Drying tubes Exhaust system
The Dryer System consists of:
Without a screen; With a screen.
The IF (intensification Factor) is the exposure required ______ divided by the exposure required ______.
Photostimulable phosphor
The Imaging Plate is made of:
Greater
The _____ the SID, the smaller the magnification.
Blower
The _______ is a fan that sucks in room air and blows it across heating coils through ductwork to the drying tubes, therefore room air should be low in humidity and free of dust.
Cassette
The _______ is the rigid holder that contains the film and the radiographic intensifying screens.
The Dryer System
The ________ extracts all residual moisture from the processed radiograph, so it drops into the receiving bin dry.
Magnification factor.
The ________ permits calculation of the actual size of an object that is projected as an image by using the formula.
Thin-film Transistor (TFT)
The _________ is an array of small pixels. Each pixel contains photodiode that absorbs the electrons and generates electrical charges.
Replenishment System
The __________ meters the proper quantities of chemicals into each tank to maintain volume and chemical activity.
EPA- Environmental Protection Agency
The _______________ sets up strict pollution guidelines pertaining to toxic waste being distributed into the water.
Sharp lines
The ability of a radiographic image to demonstrate _________ determines the quality of the recorded detail.
Detective Quantum Efficiency (DQE)
The ability of an intensifying screen to absorb x rays is called:
Ionization
The ability to remove electrons is known as?
Spatial resolution
The ability to render very small, high-density objects visibile on the image.
Tomosynthesis
The acquisition of several projection radiographs from different angles in digital form that are then reconstructed into layered images.
Enhance electron metastability
The activator in a PSP is there to:
Silver Halide Crystal
The active ingredient of the emulsion.
Increases
The air gap technique increases OID, and permits scatter to avoid the image receptor. This _______ contrast by removing scatter.
Film Speed (Sensitivity)
The amount of radiation required to produce a specified density.
Extremely small (12 degrees or less)
The anode heel effect is also more significant when using _____________ angles.
Open
The anode heel effect is more pronounced when the collimator is _________.
Lucency
The base is of uniform _______ and it is nearly transparent to light.
Dimensional Stability
The base of the film maintains its size and shape during use and processing so that it does not contribute to image distortion, known as _______.
5 gallons.
The canisters used in metallic replacement are available in a variety of sizes and depends on the amount of film processed per month. ________ is the most popular size in diagnostic imaging.
Image receptor response function.
The characteristic curve of a CR imaging plate is described as:
Penetrate an emulsion and cause an effect.
The chemicals used to process films are designed to:
Aluminum
The construction of a radiographic grid has an ______ cover to reduce scatter radiation.
Has an aluminum cover to reduce scatter radiation.
The construction of a radiographic grid:
With a grid compared with that obtained without a grid.
The contrast improvement factor is defined as the radiographic contrast obtained:
Inversely Proportional
The contrast of an image receptor is _________ to its exposure latitude, that is, the range of exposure techniques that produces an acceptable image.
Low prices; High refining costs.
The current worldwide shortage of silver is the result of little silver being mined because of __________ and ____________.
OSHA
The darkroom is considered a scientific laboratory by:
Temperature Control System
The developer temperature is maintained at 35 degrees Celsius. The wash water temperature is maintained at 3 degrees Celsius lower. Temperature is monitored at each stage by a thermocouple or thermistor and is controlled thermostatically by a controlled heating element in each tank.
D
The diagnostically useful portion of a characteristic curve most often includes which of the following? A. The base density B. The base density plus fog C. The shoulder D. The straight-line portion E. The toe
Image Contrast
The difference between adjacent densities/IR exposures. These differences can range from clear white to various shades of gray to black.
Silver Halide Crystal Concentration
The difference between fast film and slow film is:
Subject Contrast (Film)
The difference in the quantity of radiation transmitted by a particular body part as a result of the different absorption characteristics of the tissues and structures making up that part
50%
The dissolved silver averages about _______ of the silver that was originally on the film and can be recovered by a variety of methods.
Increased.
The effect of the D log E curve on contrast: As the slop of the curve becomes steeper, contrast is _________.
Actual focal spot
The effective focal spot size is controlled by the size of the _______________ (which is controlled by the length of the filament) and the anode target angle.
Grid ratio.
The efficiency of a grid for reducing scatter radiation is related principally:
Gelatin & Silver Halide Crystals
The emulsion consists of a homogenous mixture of:
3 to 5 um
The emulsion is evenly coated with a layer that is _______ thick.
Receptor Contrast (Digital)
The fixed characteristic of the receptor. Most digital receptors have an essentially linear response to exposure. This is impacted by contrast resolution (the smallest exposure change or signal difference that can be detected). Ultimately, contrast resolution is limited by the dynamic range and the quantization (number of bits per pixel) of the detector.
0.25-2.5
The generally accepted range of useful ODs on a radiograph is:
Unsharpness
The imaging process makes it impossible to produce a radiographic image without some degree of ________.
Film Contrast
The inherent ability of the film emulsion to react to radiation and record a range of density differences that a specific film is able to demonstrate.
Film Latitude
The inherent ability of the film to record a long range of density levels on the radiograph. It refers to the range of log relative exposure values that will produce density in the accepted diagnostic range.
Latent Image
The interaction of x-ray and light photons with these high Z atoms ultimately results in the formation of a _______ on the radiograph.
Has longer wavelength than the emitted light.
The laser light used in CR:
Silver
The latent image is made up of _______ atoms.
OID
The magnification factor increases with increasing:
Focal spot size
The magnification factor is not dependent on:
Plastic Bucket
The metallic replacement system incorporates a _________ that also may be referred to as a canister or cartridge.
Shape distortion
The misrepresentation by unequal magnification of the actual shape of the structure being examined. It displaces the projected image of an object from its actual position and can be described as either elongation or foreshortening.
Screen Film
The most common type of film is ________.
Geometry of Beam
The most important factor in establishing the level of resolution desired for recorded detail. X-rays come from a small point (focal spot), the further the photons move from their source, the further they diverge.
Metallic Replacement
The most widely used method of silver recovery from processing chemicals.
The temperature of the filament
The number of electrons emitted by the filament is determined by:
Dynamic range
The number of gray levels that can be rendered on the image.
Chemical Precipitation
The oldest form of silver recovery. In this method the mixing of such compounds as sodium sulfite and zinc chloride with used fixer can cause a chemical reaction. This results in the silver precipitating, or sinking, to the bottom of the tank or drum, where it can be removed.
Charge-coupled devices (CCD's)
The oldest indirect-conversion DR system is based on ___________. X-ray photons interact with a scintillation material, such as photostimulable phosphors, or CsI scintillators, and this signal is coupled, or linked, by lenses or fiberoptics that act like cameras.
Less
The patient dose at high kVp is ________ than that at low kVp.
Range of dark and light areas = shades of gray
The photons which are absorbed and transmitted create low or high density areas on an image?
High density = black areas
The photons which are actually transmitted create low or high density areas on an image?
Has shorter wavelength than the laser-stimulating light
The photostimulable emission in CR:
kVp
The primary controller of subject contrast.
Film Emulsion
The primary determinant of the D log E curve is the composition of ____________.
Contrast improvement factor (k)
The primary function of a grid is to clean up scatter and increase contrast. ___________ is the best measure of how well a grid accomplishes this function.
To provide rigid structure onto which the emulsion can be coated.
The primary purpose of the base is:
Change the silver ions of exposed crystals into metallic silver.
The principal action of developing is to:
Improve image contrast
The principle reason for using a grid is to:
Improve image contrast.
The principle reason for using a grid is to:
The energy of the incoming x-rays Composition of anatomic tissue
The probability of a total photon absorption during a photoelectric effect is dependent on:
-reduce amount of tissue being exposed -reduce patient dose -improve image contrast
The purpose of beam restriction is to:
Exposure Latitude (Film)
The range of exposure factors between minimum and maximum that will produce a diagnostic radiograph.
Dynamic Range (Digital)
The range of exposures that may be captured by a detector. The dynamic range for digital imaging is much larger than film.
Exposure Latitude (Digital)
The range of exposures which produces quality images at appropriate patient dose.
Scale Contrast (Film)
The ratio of useful densities recorded on the film. It is determined by the number of useful densities visible and the percentage of differences between them.
Phenidone
The reducing agent that is responsible for the gray tones in the film is ________.
Pairs of lines
The resolution tool is composed of _____________ a set distance from one another. The point at which a viewer can detect the closest pair of lines from each other is represents the lp/mm reading.
-Phosphor size -Phosphor layer thickness -Phosphor concentration.
The resolving power of intensifying screen depends on:
Transport
The rollers in the automatic processor are part of the ____ system.
Sulfide
The sensitivity center is usually silver _________.
Small focal spot
The sharpness of detail in a radiograph is best increased by the use of:
Replenishment System.
The silver halide crystals are suspended in the solution and eliminated with the used fixer by the _______________.
Is under mechanical control
The slow scan portion of the CR reader:
The laser
The source of the stimulating light is:
Drive Subsystem
The speed of the transport system is controlled by the speed of the motor and gear reduction system used. The tolerance on this mechanical assembly is rigid.
Total Filtration
The sum of the added filtration and inherent filtration.
Developer Tank
The temperature of the ______ is the most critical in processing film.
95 degrees F or 35 degrees C
The thermostat must maintain the temperature in the developing tank at about ____.
The dwindling worldwide supply of silver. Monetary return back to the diagnostic imaging department. Compliance with federal and state laws.
The three basic reasons for a diagnostic imaging department to institute a silver recovery program are:
Roller Transport Racks Drive Motor
The transport system consists of the following three principal subsystems:
mA
The tube current, crossing from cathode to anode.
Atomic number; tissue density
The type of irradiated material is influenced by _______ of the material or its _______.
Fixing
The underdeveloped silver is removed from the emulsion during ________.
Grid cut-off
The undesirable absorption of image-forming x-rays by a grid is called:
Water
The universal solvent is:
Environmental Protection Agency (EPA)
The used fixer and wash water contain silver in some form, which is a toxic heavy metal and therefore subject to strict pollution guidelines by the ________________ and many state regulations.
BaFlBr
The x-ray capture element of a CR imaging plate is the:
Exposed to heat
Thermoluminescent dosimeters (TLD) emit light when:
More
Thick body parts produce more or less scatter?
Upside down focused
This error occurs when a focused grid is placed upside down on the IR, resulting in the grid lines going opposite the angle of divergence of the x-ray beam.
Off center
This error occurs when the CR of the x-ray beam is not aligned from side to side with the center of a focused grid.
Off focus
This error occurs when using an SID outside of the recommended focal range.
Off Level
This error results when the x-ray beam is angled across the lead strips.
15% rule
This rule is used as a guide to maintain the same IR exposure/density when kVp changes.
Aperture Diaphragm
This type is the simplest type of collimation
Cones
This type of beam restricting device is used in dental radiography:
Long dimension linear grid
This type of grid has lead strips running parallel to the long axis of the grid.
Short dimension linear grid.
This type of grid has lead strips running perpendicular to the long axis of the grid
Screen Speed Image Noise Spatial Resolution
Three primary characteristics of radiographic intensifying screens:
Increase mAs 25%
To change from a 14" x 17" to a 10" x 12" what must be done to the mAs to obtain a quality image?
mAs
To maintain IR exposure, _______ must be changed to maintain to compensate for the exposure change.
Position the anatomy close to the image receptor.
To obtain minimum magnification, one should:
Tissue and interact with the image receptor.
To produce a radiographic image, x-ray photons must pass through:
Expose the image receptor to intense light.
To remove the image of background radiation or a previous image, one should:
Physical Contrast
Total range of density/IR exposure values recorded by the image receptor; Max contrast possible and the most accurate representation of the varying intensities present in the x-ray beam after it passed through the subject.
Visible Contrast
Total range of density/IR exposure values that can be perceived by the human eye in a single image.
Guide Shoes
Transport Rack Subassembly: When film is transported in one direction along the rack assembly, only 1 inch rollers are required to guide and proper it. At each bend, however a curved metal lip with smooth grooves guides the film around the bend. These are called ________.
Microswitch
Transport System: A _______ is engaged to control the replenishment rate of the processing chemicals.
Side rails
Transport System: Always feed film evenly, using ________ of the feed tray and alternate sides from film to film. The shorter dimension of the film should always be against the side rail, so the proper replenishment rate is maintained.
Feed Tray
Transport System: Begins at the ______, where the film to be processed is inserted into the automatic processor in the darkroom.
Entrance Rollers
Transport System: ________ grip the film as it begins its trip through the processor.
True
True or False - Fumes from the processing solutions are considered toxic, corrosive and potentially carcinogenic
False
True or False: Electrolytic Method is the most widely used method.
False
True or False: Metallic Recovery system is more expensive than the electrolytic method
True
True or False: As speed increases, so does noise.
False
True or False: Copper and Brass pipes and fittings should be used because of the corrosive effect of the processing chemicals
True
True or False: Direct exposure films contain thicker emulsion.
True
True or False: More scatter results from imaging thick body parts compared to thin body parts.
False: Direct effect on the contrast
True or False: Proper functioning of the viewbox illuminator is essential in maintaining image quality because it has a indirect effect on the contrast.
True
True or False: The overhead light should be interlocked with the film bin(s) so that if a bin is open, the light cannot be energized.
False
True/False Eating and drinking is permitted in the darkroom as long as the person eating or drinking cleans up after themselves.
False
True/False: CR has higher patient dose
False- Highe contrast resolution
True/False: CR has lower contrast resolution & wider exposure latitude
True
True/False: CR has lower repeat rate
False
True/False: Collimation & centering of part are not as critical for optimal density and contrast as compared with film/screen
False: it contributes to image noise
True/False: Compton scatter contributes to image contrast
True
True/False: If kVp is higher than 60 kVp, a grid is needed.
False: IP absorb more low energy scatter
True/False: Image Plates absorb more high energy scatter when compared with old film/screen cassettes
False, it will increase scatter radiation
True/False: Increasing field size, will decrease scatter radiation
True
True/False: Increasing grid ratio increases potential to grid cutoff
True
True/False: Ionization is characteristic of x-rays
True
True/False: Photoelectric effect is responsible total absorption of the incoming x-ray photon
True
True/False: Radiographic contrast decreases as field size increases
False- they vary per manufacturer **Disadvantage - techs are responsible for knowing which values are acceptable and which ones are not.
True/False: Sensitivity numbers and Exposure values are always the same regardless of manufacturer of equipment
Direct Exposure Film
Used to image thin body parts such as hands and feet.
Defective Quantity Effeiciency (DQE)
Used to measure the quality of a digital image by looking at the combination of the effects of noise and contrast on the imaging system.
Line Focus Principle
Used to reduce the effective area of the focal spot--this permits the best resolution of detail while permitting as large an actual area as possible.
Silver Extraction Type Unit
Uses a foam filter that is impregnated with steel wool. The silver from the used fixer solution replaces the iron in the steel wool. -More efficient at removing silver from used fixer and lasts longer than a simple steel wool metallic replacement unit.
Steel Wool Metallic Replacement Unit
Uses steel wool to filter solution. Silver replaces the iron in the steel wool and can be removed easily after significant accumulation in a canister or replacement cartridge occurs.
Grid matches the size of the cassette and it used by placing it on top of the IR; To prevent them from moving during the radiographic procedure
Wafer Grid: Describe this grid; Why are they generally taped to the IR?
Washing
Water is used as the wash agent. The temperature of the water should be maintained approximately 3 degrees Celsius below the developer temperature.
Quality and Quantity of x-ray beam
What affects the interaction within various tissues that make up the anatomic part?
Speed Size Film contrast Distribution
What are 4 performance characterisitcs of film?
1. Magnification 2. Distortion 3. Focal-spot blur
What are the geometric factors?
25 to 45 lines/cm (60 to 110 lines/inch)
What are the grid frequencies ranges?
Kodak Wratten 6B or the Kodak Mor-Lite
What are the most common types of filter used for blue violet sensitive film?
1. Use shortest possible exposure time 2. Restrict patient motion by providing instruction or using restraining device 3. Use large SID 4. Use small OID
What are the procedures for reducing motion blur?
Phenidone & Hydroquinone
What are the reducing agents in the developer?
Diaphragms Cones Collimators
What are the three types of beam restricting devices?
Base and emulsion
What are the two main parts of radiographic film?
Beam restricting devices & grids
What are the two principle means to reduce scatter radiation?
Overhead lights Safelights
What are the two types of lighting a darkroom should have?
Remnant ray Compton interaction
What are the two types of x-rays responsible for OD?
Metalic Replacement & Electrolytic Method
What are two methods of silver recovery units?
Sensitivity Center
What characteristic of emulsion makes it x-ray sensitive?
Amber colored safelight
What color safelight is used for blue violet film?
Total Darkness
What condition is necessary for film manufacturing?
It consists of a thermometer with wet and dry bulbs
What does a pyschometer consists of?
Image artifacts
What does backscatter cause?
Limit the field size to reduce scatter and primary radiation.
What does beam restricting devices do?
Silver Halide and Gelatin
What does emulsion consists of?
Adds unwanted exposure (fog)
What does scatter do to an image?
Decreases image contrast
What does scatter do to image contrast?
Density is decreased Noise is increased
What happens as a result of the less photons reaching the IR to density and noise?
The energy slowly dissipates and the latent image fades
What happens if an IP is not processed right away?
It may fog - Fog is non-informational density that occurs because silver grains are formed and do not represent any of the anatomic structures within the patient.
What happens if film is not put in a controlled environment?
Potential overexposure of patients
What happens if you are not centered correctly?
Compton interactions are increased
What happens the percentage of Compton interactions as the kilovoltage is increased?
Degrades film and ventilation removes fumes from processing solutions which may sensitize film emulsions
What happens to film f you have too much heat and humidity?
mA must be increased proportionally to provide the required x-ray intensity
What happens to mA when exposure time is reduced?
It generally decreases
What happens to the percentage of photoeletric interactions as the kilovoltage increases?
It does not contribute any useful information
What happens when a scattered photon strikes the image receptor?
Contribute to radiation exposure to patient
What happens when the scattered photons are absorbed within the anatomic tissue?
It will reduce the # of photon interactions
What happens when you increase the energy of the x-ray beam to photon interactions?
It will increase transmission
What happens when you increase the energy of the x-ray beam to transmission?
Scatter radiation
What increases as the field size of the x-ray beam increases?
A device that has very thin lead strips with radiolucent interspaces
What is a grid?
Film transfer systems
What is a passbox?
Transmitted and scattered radiation
What is a remnant x-ray composed of?
A light source that emits wavelengths to which particular types of film are not sensitive.
What is a safelight?
Exposure of the emulsion caused by light from opposite side of intensifying screen.
What is crossover?
Light emitted while the phosphor is stimulated.
What is fluorescence?
Recommended range of SIDs that can be used with a focused grid
What is focal range?
Refers to the orientation of the lead lines to one another
What is grid focus?
Refers to the linear pattern of the lead lines of a grid
What is grid pattern?
Degree of blackening on a radiograph.
What is optical density?
After glow, it reduces detail/resolution.
What is phosphorence?
Random fluctuation in optical density of the image
What is radiographic noise?
Those that pass through the patient without interacting.
What is remnant x-ray?
100 nm
What is the approximate diameter of the laser beam?
1%
What is the approximate percentage of x-rays that are transmitted through a patient?
Polyester
What is the base of radiographic film made of?
The thickness and rigidity of the base.
What is the difference between x-ray film and photographic film?
To absorb scatter before it reaches the image receptor.
What is the function of a grid?
To protect film from white light and ionizing radiation during handling and processing
What is the function of the darkroom?
To absorb the energy of the x-rays and with it, image the body part
What is the function of the phosphor?
Prolong the life of the solutions.
What is the function of the preservative in the developer and fixer?
To absorb scatter radiation emitted from the patient
What is the intended function of a grid?
Focal-spot blur
What is the most important factor for determining spatial resolution?
Grid ratio
What is the most important grid characteristic?
kVp
What is the most important influence on subject contrast?
mAs
What is the primary control of optical density (OD)?
kVp
What is the primary control of radiographic contrast?
A reduction in the number of photons reaching the IR
What is the primary radiographic effect of grid cuttoff?
Provide mechanical support for silver halide crystals by holding them uniformly dispersed in place.
What is the principal function of gelatin?
Analog vs. Digital
What is the principle difference between screen-film radiography and CR?
Expose/read/erase
What is the proper sequence for producing a computed radiographic image?
Fixer tank
What is the second tank in an automatic processor?
An aperture diaphragm.
What is the simplest of all beam-restricting devices?
1.0um
What is the size of the silver halide size?
68 degrees or below; Excessive heat could result in loss of contrast.
What is the temperature radiographic film should be stored at?
If the incoming x-ray photon passes through the anatomic part without any interaction with anatomic structures
What is transmission?
Patient motion
What is usually the cause of motion blur?
Psychrometer
What measures humidity in a darkroom?
California
What state requires three borders of collimation to be seen on the film?
mAs
What technical factor is increased when using a grid?
Fluorescence and Phoshprescence
What two types of luminescence (emission of light after stimulation) involve outershell electrons?
White light
What type of light is used for standard lighting?
Image Forming and Remnant X-rays
What type of radiation exiting the patient is responsible for the latent image formation?
Improve it
What will the reduced scatter do to contrast resolution?
Uranium
What would be the most acceptable grid strip material from the standpoint of x-ray attenuation?
1 cm unexposed border should be visible on all sides
When a diaphragm is used:
A 1-cm unexposed border should be visible on all sides.
When a diaphragm is used:
Maintain the same number of x-ray photons reaching the IR
When a grid is added to the IR, mAs must be increased to do what?
Patient dose is increased
When air-gap radiography is performed:
X-ray field cutoff can occur if the diaphragm is not properly positioned
When an an aperture diaphragm is used:
Increase
When an increase in mAs is compensated for a decrease in kVp, patient dose will _________.
To determine the adjustment in mAs Changing from grid to nongrid (vice-versa) Changing to grids with different grid rations
When and why is the grid conversion factor used?
X-ray field cutoff can occur if the diaphragm is not properly positioned
When aperture diaphragm is used:
Increase, Decrease
When body part increases or field size increases, scatter will ________, and subject contrast will ________.
C.
When comparable radiographs are produced, which of the following combinations will result in the lowest patient dose? A. High kVp and high-ratio grids B. High kVp and low ratio grids C. High kVp and no grid D. Low kVp and high ratio-grids E. Low kVp and low-ratio grids
mAs
When distance is fixed, ______ is the variable factor which is used to control optical density.
If the object plane and image plane are not parallel
When does distortion occur?
When the focal spot is not a point
When does focal-spot blur occur?
Crossover Rack
When film exits the top of the rack assembly, it is guided to the adjacent rack assembly through the __________. Found at the junction at the junction between adjacent tanks. (not submerged in solution)
A convergent point
When imaginary lines drawn above a linear focused grid from each lead strip it is called:
Rule of Thumb
When increasing distance, double the mAs for each change. When decreasing distance, halve the mAs for each change.
Patient dose
When kVp is increased with a compensating reduction in mAs, ________ is reduced.
B
When kVp is increased with a compensating reduction in mAs, which of the following is reduced? A. Optical density B. Patient dose C. Remnant radiation D. Scatter proportion E. Spatial resolution
2mm
When lining the walls, floor and ceiling it should be with at ______ of lead.
Decreased
When mAs is decreased, patient dose is _________.
Proper mask Nitrile gloves Protective glasses
When one is mixing solutions, cleaning the processor, or near processing solutions, they should:
Red
When rare earth screens are used what type of safelight is required?
at least semiannually or more frequently if problems are discovered
When should a safelight test be performed?
A remnant x-ray
When the attenuated x-ray beam leaves the patient, the remaining x-ray beam is called:
Increased; Decreased
When the difference between adjacent thicknesses of various body parts is great, subject contrast is __________. When there is little difference, subject contrast is _________.
Increase
When the difference in tissue densities is great, subject contrast will _______.
Reduce the density on the image.
When the field size is reduced, the resulting reduction in scatter will do what to the density?
Hardener
When the films that drop from the processor are damp, the usual depletion of the _____ is the cause.
Penumbra will be reduced
When the focal spot is switched from large to small:
Static Artifacts
When the humidity drops below 40%, it can cause _______.
Photostimulable luminescence
When the material emits light some time later when exposed to a different light source it is called:
Creative alignment
When the position of the body part or object within the body do not permit alignment, _________ is utilized.
Penumbra
When there is poor film/screen contact, the image detail is not as sharp due to increased ____________.
1981
When was CR introduced in the U.S?
1994
When was the requirement for PBL repealed?
Sensitivity Center
Where does the metallic silver accumulate?
In the active layer of the CR image plate
Where is barium fluorohalide found?
Small on anode/positive side and large on cathode/negative side
Where is focal-spot blur small and large?
Bewteen patient and IR
Where is the grid placed?
Sodium Carbonate
Which chemical in the developer causes the film emuslsion to swell?
Lightproof maze
Which darkroom design requires the most square footage?
Grids and beam restrictors.
Which of the following are the two general types of devices designed to control scatter radiation?
C.
Which of the following are the two general types of devices designed to control scatter radiation? A. Filtration and beam restrictors B. Filtration and image masks C. Grids and beam restrictors D. Grids and filtration E. Image masks and beam restrictors
c. Ammonium Thiosulfate
Which of the following chemicals found in the fixer is the clearing agent? a. Sodium Sulfite b. Potassium alum c. Ammonium Thiosulfate
B.
Which of the following devices is normally designed to limit off-focus radiation? A. Added filtration B. First-stage shutters of a variable-aperture collimator C. Fixed-aperture circular diaphragm D. Fixed-Aperture rectangular diaphragms E. Second-stage shutters of a variable-aperture collimator.
B.
Which of the following devices is normally designed to limit off-focus radiation? A. Added filtration B. First-stage shutters of a variable-aperture collimator C. Fixed aperture circular diaphragms D. Fixed aperture rectangular diaphragm.
B
Which of the following factors that affect scatter radiation can be controlled by the radiologic technologist? A. Added filtration B. Field size C. Inherent filtration D. mAs E. Patient thickness
B.
Which of the following factors that affect scatter radiation can be controlled by the radiologic technologist? A. Added filtration B. Field size C. Inherent filtration D. mAs. E. Patient thickness.
A.
Which of the following is a beam restricting device? A. 2.5 mm Al added filtration B. A cone without and integral diaphragm C. A rectangular film mask on a viewbox D. A fluoroscopic spot-film device E. PBL
E.
Which of the following is an undesirable characteristics of linear grids compared with focused grids? A. Higher Bucky factor B. Increased patient dose C. Lower grid frequencies D. Lower grid ratios E. More grid cutoff
B.
Which of the following is monochromatic? A. Infrared light B. Laser light C. Stimulated emission D. Visible light E. X-ray beam
A.
Which of the following is most intense? A. Laser light B. Normal visual light C. Optical lense support D. Stimulable Emission E. X-ray beam
B.
Which of the following is most responsible for radiographic spatial resolution? A. Film graininess B. Focal-spot size C. Screen mottle D. SID E. Use of a grid
D.
Which of the following is not a beam restricting device? A. A cone B. A PBL device C. A variable- aperture collimator D. Added filtration
D.
Which of the following is not a beam-restricting device? A. Cone B. PBL device C. A variable-aperture collimator D. Added filtration
E.
Which of the following is not a device designed to reduce the level of scatter radiation that reaches the image receptor? A. Beam restrictor B. Collimator C. A compression device D. A diaphragm E. A test pattern
C.
Which of the following is not a devices designed to reduce the level of scatter radiation that reaches the image receptor? A. A beam restrictor B. A collimator C. A compression device D. A diaphragm E. A test pattern.
A.
Which of the following is not a grid positioning error? A. Air-gap grid B. Lateral decentering C. Off-center grid D. Off-focus grid E. Off-level grid
A.
Which of the following is not a photodetector? A. ADC B. CCD C. CMOS D. PD E. PMT
D.
Which of the following is not necessary for constructing a characteristic curve? A. Densitometer B. Processor C. Sensitometer D. Slit camera E. Step wedge
D.
Which of the following is the least important indicator of grid performance? A. Contrast improvement factor B. Grid frequency C. Grid mass D. Grid strip height E. Grid ratio
B
Which of the following is the main component of radiographic noise? A. Graininess B. Quantum mottle C. Random mottle D. Structure mottle
D.
Which of the following is the most important grid characteristic? A. Grid frequency B. Grid height C. Grid mass D. Grid ratio E. Grid weight
D.
Which of the following is the simplest of all beam-restricting devices? A. Fluoroscopic collimator B. Radiographic cone C. Aluminum filter D. Aperture diaphragm E. PBL
D.
Which of the following is the simplest type of grid? A. Crossed grid B. Focused grid C. High-ratio grid D. Linear grid E. Zero frequency grid
B.
Which of the following materials would be most radiolucent? A. Aluminum B. Carbon fiber C. Copper D. Iodine E.Lead
B.
Which of the following materials would be most radiolucent? A. Aluminum B. Carbon fiber C. Copper D. Iodine
C.
Which of the following processes is most responsible for the production of scatter radiation? A. Bremsstrahlung B. Characteristic interactions C. Compton effect D. Photoelectric effect E. Transmission
C.
Which of the following processes is most responsible for the production of scatter radiation? A. Bremsstrahlung interaction B. Characteristic interaction C. Compton effect D. Photoelectric effect E. Transmission
C.
Which of the following radiographic techniques should result int the widest exposure latitude? A. High kVp, contrast film, high grid ratio B. High kVp, direct exposure, high grid ratio C. High kVp, latitude film, low grid ratio D. Low kVp, direct exposure, high grid ratio E. Low kVp, screen film, low grid ratio
D.
Which of the following steps can be eliminated during switching from screen-film radiography to CR?
D.
Which of the following will not improve image contrast? A. A decrease in kVp B. Collimating the x-ray beam C. The used of a grid D. The use of added filtration E. The use of positive-beam limitation (PBL)
D.
Which of the following would be included in the three major classifications of moving grids? A. Grossed grid B. Focused grid C. Linear grid D. Reciprocating grid E. Zero frequency grid
E.
Which of the following would be the most acceptable grid strip material from the standpoint of x-ray attenuation?
Gustav Bucky in 1913
Who invented the grid? And in what year?
They determine the focal distance of a focused grid
Why are both the convergent line and convergent point important?
Cracks or pinholes in the filter The wrong wattage of the bulb being installed
Why are some reasons safelights may become unsafe over time?
To match the angle of divergence of the primary beam
Why are they angled or canted?
It is a mixture of all of the colors in the visible light spectrum mixed together
Why cant an ordinary room light be used as a safelight?
The coloring reduces eyestrain and fatigue, enhancing the radiologist's diagnostic efficiency and accuracy.
Why is the film tinted blue?
It is used to determine the focal range of a focused grid.
Why is the grid radius/focal distance important?
To prevent buildup of heat and humidity
Why must a darkroom be well venitated?
Reduce the risk of static electricity
Why should countertops and work surfaces be grounded in the darkroom?
Edge enhancement Subtraction Post processing Contrast
With CR, images can be easily manipulated by:
Yes
With stationary grids can you see grid line on the image?
90 kVp - the percentage of Compton interaction increases as kVp increases
Would 90kVp or 70kVp result in more scattered imaging forming beam?
Transmitted in the body
X-rays that the technologist would like to have interact with the image receptor are those that are:
Sludge
_____ can build up on rollers since the filters are not 100% efficient; so cleaning of tanks and transport systems should be part of routine maintenance of any processor.
Low
_____ contrast film produces an image with more gray
High
_____ contrast film produces very black and white images.
Heat
_____ increases the fog of a radiograph therefore reduces contrast.
Hydroquinone & Phenidone
______ & ______ are combined for rapid processing.
Size & Concentration
______ & ______ of silver halide crystals affect film speed.
Hydroquinone
______ acts rather slowly but is responsible for the very blackest shades.
kVp
______ affects production of scatter.
Screen Speed
______ is a relative number that describes how efficiently x-rays are converted into light.
Low
______ kVp produces higher subject contrast---low energy photons are absorbed by thicker parts while penetrating the thinner parts.
Water
______ must be circulated through the wash tank to remove all the processing chemicals from the surface of the film before drying; this ensures archival quality. Fresh tap is piped into the tank at the bottom and overflows the top where it is collected and discharged to the sewer system. Minimum flow rate for each wash is 12L/min
50%; 50%
______ of the silver is dissolved in the fixer. The other_____ remains on the film.
Contrast Resolution
_______ refers to the ability to image similar tissues as the liver and pancreas or gray matter and white matter.
Composition
________ of radiographic emulsion is a proprietary secret that is closely guarded by each manufacturer.
Phenidone
_________ acts rapidly and influences the lighter shades of gray.
Direct Exposure Film
_________ contains a thicker emulsion with more silver halide crystals than screen film.
Filtration
_________ is inversely related to density/IR exposure.
Gluteraldehyde
_________ is put in the developer solution to harden the film and control emulsion swelling.
Spatial Resolution
_________ refers to how small an object can be imaged.
E.
__________ film has the highest amount of silver in place. A. Processed film B. Exposed film but not processed C. Unprocessed film but not exposed D. A only E. B & C
Archival
__________ film is film that has been exposed and processed and has outlived its use as a patient record.
Screen Speed
__________ is a relative number that describes how efficiently x-rays are converted into light.
Green film
___________ is film that has not been processed such as film that has expired or film that was accidentally exposed to white light (such as an open film bin). This is the most valuable film because all of the silver is in place. Because of this higher value, it is recommended that this film be separated from other categories of film to be sold and that a higher price per pound be negotiated Usually about 0.4 troy oz of silver per 14 × 17 inch.
Scrap Exposed
____________ film is film that has been exposed and processed such as rejects, old sensitometry films and even dry laser print films obtained from digital systems. Usually about 0.11 troy oz of silver per 14x17 inch.
Indirect conversion
____________ is a two-step process x-ra photons strike a scintillator that produces light and that light strikes the amorphous silicon allowing the conduction of electrons into the detector.
Water Pollution Act of 1972
______________ bans the placement of toxic substances in in public waterways and sewer system
Aperture Diaphragm
___________are basically lead or lead lines metal devices placed in the beam to restrict the x-rays emitted from the tube.
-Controls the energy, therefore the strength of the electrons striking the target of the x-ray tube for any given mAs. -Controls the average energy of the x-ray photons produced at the anode target.
kVp alters the intensity of the beam reaching the IR in two ways.
Directly
mA is ______ proportional to tube current.
The number of x-rays produced
mA selected determines _____________ and therefore the radiation quantity.
Decreased
mAs alters image receptor exposure, if exposure causes density/IR exposure differences out of range, such as under/overexposued----Contrast is _______.
