Term
| What are 6 different types of IRs? |
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Definition
1. Film
2. Fluoroscopic I/I
3. TV
4. Laser Image
5. Solid State Detector
6. CR Plate |
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Term
| What are 6 types of specialty film? |
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Definition
1. Direct Exposure Film
2. Mammography Film
3. Video Film
4. Duplication Film
5. Subtraction Film
6. Dental Film |
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Term
| What are the two primary parts of x-ray film? |
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Definition
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Term
| ___________ _________ refers to a film that has a base layer that maintains its size and shape during use and processing so that no dimension of the film is changed. The base of the film is responsible for this characterisitic. |
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Definition
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Term
| Between the emulsion and the base is a thin coating of material called the ________ layer, which ensures uniform adhesion of the emulsion to the base. |
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Definition
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Term
| The ________ layer allows the emulsion and the base to maintain proper contact and integrity during use and processing. |
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Definition
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Term
| The emulsion is enclosed by a protective covering of gelatin called the ________. |
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Definition
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Term
| The ________ protects the emulsion from scratches, pressure, and contamination during handling, processing, and storage and allows for relatively rough manipulation of x-ray film before exposure. |
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Definition
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Term
| Another name for overcoat: |
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Definition
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Term
| What are the 7 layers of double emulsion film? (in order) |
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Definition
1. Overcoat (Supercoat)
2. Emulsion
3. Adhesive
4. Base
5. Adhesive
6. Emulsion
7. Overcoat (Supercoat)
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Term
| What are the 4 layers of x-ray film? (in this case, single-emulsion film) |
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Definition
1. Overcoat (Supercoat)
2. Emulsion
3. Adhesive Layer
4. Base |
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Term
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Definition
| It is the ability of a material to allow light to pass through. The material is almost transparent. |
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Term
| What are two reasons why manufacturers tint film blue? |
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Definition
1. To reduce the radiologist's eyestrain and fatigue
2. To increase the radiologist's efficiency and accuracy |
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Term
| What is the progressive history of the material of x-ray film? |
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Definition
1. Glass
2. Cellulose Nitrate
3. Cellulose Triacetate
4. Polyester
5. Computed Radiography (no film)
6. Digital Plate IRs (no film) |
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Term
| What are 4 advantages that polyester base film has over other types? |
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Definition
1. More resistant to warping from age
2. It is stronger
3. Better dimensional stability
4. Thinner than previous bases
5. (Bonus: it is not flammable) |
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Term
| What is the "heart" of the film? |
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Definition
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Term
| What are the two primary components of film emulsion? |
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Definition
1. Gelatin
2. Silver Halide Crystals |
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Term
| This material makes up part of the film emulsion. It's principle function is to provide mechanical support for silver halide crystals by holding them uniformly dispersed in place. What material is it? |
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Definition
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Term
| What is the "active ingredient" of the film emulsion? |
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Definition
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Term
| The ______ _____ is the invisible image present on the x-ray film after exposure before being processed. |
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Definition
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Term
| The shape and latice structure of silver halide crystals are not perfect. There is a chemical imperfection in the crystals that causes photoelectrons and silver ions to be attracted to something called the ___________ ______, where the phoelectrons and silver ions form a latent image center of metallic silver. |
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Definition
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Term
| What is the latent image called after final processing is complete? |
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Definition
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Term
| What are the four primary film screen characteristics? |
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Definition
1. Intensification Factor
2. Speed
3. Image Noise
4. Spatial Resolution |
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Term
| Screen _____ is defined as how efficiently x-rays are converted into visible light. |
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Definition
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Term
| _________ is the exposure of an emulsion caused by light from the opposite radiographic intensifying screen. |
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Definition
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Term
| The proper matching of the sensitivity of a film emulsion to the light spectrum emitted by the radiographic intensifying screen is called what? |
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Definition
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Term
| What are the 5 major film handling considerations? |
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Definition
1. Heat and Humidity
2. Light
3. Radiation
4. Shelf Life
5. Handling and Storage |
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Term
| What is the sequence of film development? |
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Definition
1. Developing
2. Fixing
3. Washing
4. Drying |
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Term
| What did the term wet reading originate from? |
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Definition
| Back when film was the sole IR medium being used, radiologists would sometimes examine x-rays while the film was still wet if the pt. was in critical condition. |
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Term
| What happens during film processing? |
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Definition
| The film is wetted to permit chemicals to pass through the overcoat and develop the latent image into the manifest image. The film is placed in fixer to harden the protective coating, any remaining chemicals are washed off, and the film is then dried. |
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Term
| What are the 5 major components of the automatic processor? |
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Definition
1. Transport
2. Temperature
3. Circulation
4. Replenishment
5. Dryer |
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Term
| Besides the typical automatic processor, what are some other types of processing units? (Name 4) |
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Definition
1. Rapid Processing
2. Extended Processing
3. Daylight Processing
4. Dry Processing |
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Term
| What are 7 advantages of dry processing? |
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Definition
1. Elimination of handling, maintenance, and disposal of chemicals
2. No darkroom required (space saved)
3. No plumbing required
4. Less environmental impact
5. Reduced capital cost
6. Reduced operating cost
7. Higher throughput |
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Term
| What is the major ingredient in intensifying screens? |
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Definition
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Term
| What was the original active substance in intensifying screen phosphor? |
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Definition
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|
Term
| What are the 3 basic rare earth crystals? |
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Definition
| gadolinium, lathanum, and yttrium |
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Term
| What are the layers of the intensifying screen? |
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Definition
1. Protective Coating
2. Phosphor
3. Reflective Layer
4. Base |
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Term
| What are the 4 major characteristics of the protective layer? |
|
Definition
1. Protects against abrasion and damage caused by handling
2. Helps to eliminate static electricity
3. Provides a surface for routine cleaning without disturbing the active phosphor
4. Is transparent to light |
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Term
| The emitted visible light in response to some outside stimulation is called: |
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Definition
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Term
| If visible light is emitted only while the phosphor is stimulated, the process is called ____________. |
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Definition
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Term
| If phosphor continues to emit light after stimulation, this is called _______________, ______ ___, or _________. |
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Definition
| phosphorescence, screen lag, or afterglow |
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Term
| What are the 3 primary characteristics of intensifying screens? |
|
Definition
1. Screen Speed
2. Image Noise
3. Spatial Resolution |
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Term
| What are 6 properties of radiographic intensifying screens that the radiographer cannot control? |
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Definition
1. Phosphor Composition
2. Phosphor Thickness
3. Reflective Layer
4. Dye
5. Crystal Size
6. Concentration of phosphor crystals |
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Term
| What are 3 properties that affect the radiographic intensifying screen that the radiographer can control? |
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Definition
1. Radiation Quality
2. Image Processing
3. Temperature |
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Term
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Definition
| It is the sensitivity of the screen-film combination to x-rays and light. |
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Term
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Definition
| It is an intensifying screen characteristic that reduces contrast. It is mostly caused by fast screens and high kVp. |
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Term
| _______ resolution can be defined as how small an object can be imaged. |
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Definition
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Term
| The _______________ factor is the rate of exposure without a screen to that with a screen to produce the same optical density. |
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Definition
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Term
| What is the "Detective Quantum Efficiency" - DQE? |
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Definition
| It represents the probability that an x-ray will be absorbed by a radiographic intensifying screen. |
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Term
| What is "Conversion Efficiency" - CE? |
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Definition
| It represents the amount of light emitted by each x-ray absorbing event. |
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Term
|
Definition
| IF = exposure required without screens / exposure required with screens |
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Term
| What is the principle advantage of rare earth intensification screens? |
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Definition
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Term
| What are the 6 most common causes of poor screen film contact? |
|
Definition
1. Worn radiolucent foam
2. Loose, bent, or broken hinges
3. Loose, bent, or broken latches
4. Warped screens caused by excessive moisture
5. Warped cassette front
6. Foreign matter under the screen |
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Term
| ________ resolution can be defined as the ability to image adjacent similar tissues. |
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Definition
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Term
| More black and white = (high/low) contrast |
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Definition
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|
Term
| More shades of gray = (high/low) contrast |
|
Definition
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Term
| Name 8 factors that can affect image contrast: |
|
Definition
1. mAs
2. Anode Heel Effect
3. Distance
4. Filtration
5. Processing
6. Anatomical Part
7. Beam Restrictors
8. Grids |
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Term
| Name 3 factors that contribute to increased scatter radiation: |
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Definition
1. Increased kVp
2. Increased patient thickness
3. Increased field size |
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Term
| What two types of x-rays are responsible for the optical density and contrast of a radiographic image? |
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Definition
1. Those that pass through the patient without interacting with the patient
2. Those that are scattered within the patient through compton ineraction |
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Term
| What is the purpose of beam restricting devices? |
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Definition
| A beam restricting device's purpose is to improve image contrast by minimizing scatter radiation by limiting the x-ray field size to only the anatomy of interest. |
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Term
| What are the two major effects of using beam restricting devices? |
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Definition
1. Reduced scatter radiation
2. Improved image contrast |
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Term
| What are the 3 types of beam restricting devices? |
|
Definition
1. Aperture diaphragm
2. Cones or cylinders
3. Variable-aperture collimator |
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Term
| What is the collimator rule? |
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Definition
| The size of the collimated x-ray field should be adjusted to the smallest reasonable size that will include the portion of the body to be imaged, and it should never be larger than the size of the film/IR. |
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Term
|
Definition
| It stands for "Positive Beam Limiting". It is a type of collimator capable of sensing the size of a cassette in the bucky and automatically collimating the x-ray beam to the size of the receptor. |
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|
Term
| What is the primary purpose of a grid device? |
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Definition
| A grid's primary purpose is to improve image contrast by cleaning up scatter. |
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Term
| What is the difference between the grid and other beam restricting devices? |
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Definition
| The grid is the only device that cleans up scatter radiation in-between the patient and IR. |
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Term
| A ____ is a carefully fabricated series of section of radiopaque material alternating with sections of radiolucent material. |
|
Definition
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|
Term
| Who invented the grid? When did he invent it? |
|
Definition
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|
Term
| What typical thickness of a body part should you start to consider the use of a grid? |
|
Definition
| > 10 cm; typically anything as big or bigger than the knee on an average patient |
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|
Term
|
Definition
| Grid frequency is the # of grid strips (grid lines) per inch or centimeter; higher grid frequency = more exposure required |
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|
Term
| What is the grid ratio formula? |
|
Definition
| Grid Ratio = h/D (h = height of grid / D = width of interspace material) |
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|
Term
| How do you determine the % x-ray absorption? |
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Definition
| % x-ray absorption = (width of grid strip / width of grid strip + width of interspace) x 100 |
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|
Term
| When referring to grids. What does clean-up mean? |
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Definition
| It means that the grid absorbs the scatter radiation - thus cleaning it up. |
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Term
|
Definition
| A grid ratio is the height of the grid divided by the interspace width. High-ratio grids are more effective in cleaning up scatter radiation than are low-ratio grids. This is because the angle of scatter allowed by high-ratio grids is less than that permitted by low-ratio grids. |
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Term
| What is the formula for grid frequency? |
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Definition
| Grid Frequency = 10,000 μm/cm ÷ (T+D) μm/line pair; T = thickness of grid strip, D - the width of the interspace material |
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Term
| What kind of interspace material is used? |
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Definition
| plastic fiber or aluminum |
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|
Term
| What is the purpose of the interspace material? |
|
Definition
| To maintain precise separation between the delicate lead strips within the grid |
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|
Term
| Define contrast improvement factor (K): |
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Definition
| The contrast improvement factor (K) is the ratio of the contrast of a radiograph using a grid vs the contrast of the same radiograph without a grid. |
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Term
| When a grid is used, the radiographic technique must be increased to produce adequate OD. This is known by what two names? |
|
Definition
1. Bucky Factor
2. Grid Conversion Factor (GCF) |
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|
Term
| What is grid selectivity? |
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Definition
| selectivity of a grid is the ratio of transmitted primary radiation through the grid to transmitted scatter radiation through the grid. |
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|
Term
|
Definition
1. Parallel
2. Crossed
3. Focused
4. Moving |
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|
Term
| What are 4 common grid problems? |
|
Definition
1. Off-level
2. Off-center
3. Off-focus
4. Upside-down |
|
|
Term
| What are 2 types of moving grids? |
|
Definition
1. Reciprocating
2. Oscillating |
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|
Term
| What is the focal distance/grid radius? |
|
Definition
| It is the distance between the grid and the convergent line or point. It determines the focal range. |
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|
Term
| What is the focal range of a grid? |
|
Definition
| The recommended range of SIDs in which the grid can be used as determined by the focal distance/grid radius. |
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|
Term
|
Definition
If imaginary lines were drawn from each of the lead lines in a linear
focused grid, these lines would meet to form an imaginary point called the
convergent point. If points were connected along the length of the grid,
they would form an imaginary line called the convergent line. Both the
convergent line and the convergent point are important because they
determine the focal distance of the focused grid. |
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|
Term
| What are the general rules of grid characteristics? |
|
Definition
1. High ratio grids have high contrast improvement factors.
2. High frequency grids have low contrast improvement factors.
3. Heavy grids have high selectivity and high contrast improvement factors. |
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|
Term
| What are the 2 components of "Visibility Detail"? |
|
Definition
|
|
Term
| What are the components of a conventional image receptor? |
|
Definition
1. Cassette
2. Radiographic Intensifying Screen
3. Film |
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|
Term
| The contrast of an IR is _________ proportional to its exposure latitude. |
|
Definition
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