Rad 141 Test #3 Review

gupevele's version from 2015-11-17 16:40

Grids - Construction and Type

Question Answer
A grid is a device placed between the patient and the _____ to absorb _____ radiation and improve _____image receptor; scattered; contrast
Potter made the grid more practical by _____ it during the exposuremoving
The grid is constructed of alternating strips of _____ and _____ materiallead; interspace
To maintain density, you must _____ your exposure factor when using a gridincrease
A grid with the strips going in one direction only is referred to as a _____ gridlinear
A grid with the strips angled toward the center of the center of the grid is referred to as a _____ gridfocused
The distance from the point of convergence to the center of the grid is called the grid _____radius (or grid focusing distance)
Which of the following determine the amount of grid efficiency obtained by a grid? (a. grid frequency, b. grid radius, c. grid ratio, d. grid selectivity)a, c, d (grid frequency, grid ratio, grid selectivity)
The height of the lead strips to the distance between them is called the grid _____ratio
The number of lines per inch in the grid is called the grid _____frequency
Which of the following does NOT take into account the "diverging" x-ray beam? (a. crosshatched, b. focused, c. linear, d. nonfocused)d. nonfocused/parallel grid)
Loss of density due to absorption of primary radiation by the grid is called grid _____cutoff
Percentage of allowable error in centering, leveling, and target grid distancepositioning latitude
|||||||||||| } Which way can you angle the x-ray tube on these lines to not produce grid cutoff?parallel with the lines

Advantages/Disadvantages of Grids

Question Answer
Grids require an _____ in exposure factors to maintain radiographic image density over non-grid techniquesincrease
A grid should be used with a body part measures at least _____cm in thickness, and procedures that require more than _____KVP10-12; 60
The higher the grid ratio, the less _____ and _____focusing; positioning latitude
A _____ grid ratio gives the most positioning latitudelow
Nonfocused/parallel grids function best with a _____ field size and a _____ SIDsmall; long
Grid that is ideal for portables using 8x10 or 10x12 image receptors and a long SIDnonfocused/parallel
Grid designed to allow the primary beam to pass through more easily due to the slanting/angling of the lead stripsfocused
Focused grids are arranged to take advantage of the _____diverging x-ray beam
SID limitations of a focused grid are determined by _____grid radius/grid focusing distance
Which technique will provide MORE contrast? (grid/nongrid)grid
Which grid allows you to utilize a tube angle without grid cutoff? (crosshatched/linear)linear
Which grid permits you to use any SID without significant grid cutoff? (focused/nonfocused)nonfocused/parallel
Which grid will not demonstrate grid lines? (moving/stationary)moving
Which grid will demonstrate grid cutoff on a radiograph on short SIDs and large film sizes? (focused/nonfocused)nonfocused/parallel
Which grid has a specific tube side and a limited focal range? (focused/nonfocused)focused
Which grid ratio possesses a poor/limited positioning latitude range? (low/high)high
True or false: A tube angled against lead strips will NOT cause grid cutofffalse
True or false: A focused grid use upside down will cause grid cutofftrue
True or false: Using an SID out of focal range of the grid will NOT cause grid cutofffalse
True or false: Using a stationary grid will cause grid cutofffalse; but it will give you grid lines
True or false: The bucky switch NOT being activated will cause grid linestrue
True or false: The exposure starting before grid movement is at full speed will NOT cause grid linesfalse
True or false: The grid needs to be perpendicular to the tube in order for there to be no grid linestrue
True or false: Using a grid cassette will cause grid linestrue
Cutoff: X-ray tube is shifted to the left or right of the center of the gridoff-center
Cutoff: Only the center of the image is goodupside down focused grid
Cutoff: Using an SID beyond the grid radius of a focused gridoff focus
Cutoff: Angling the x-ray tube across the lead strips of a gridoff level (can angle with the strips, but not against)

Grid Cutoff

Question Answer
Off-Level Grid - Grid is at an angle to the tube (tilted)
Off-Center Grid - Grid and tube aren't lined up correctly
Off-Focus Grid - SID is too long or short
Upside-Down Grid - Grid literally upside down, center is fine, but top and bottom are cut off

Subject Contrast

Question Answer
3 factors that change the amount of scatter radiation producedKV used, thickness of the part, changes in tissue density
Disease decreases image contrast due to more scatter radiation producedadditive/radiopaque
Disease alters contrast depending on whether it is _____ or _____, as well as the extent of the disease processadditive; destructive
Images with gas and bone tissue will display _____ contrasthigh
Images with muscle and solid organs will display _____ contrastlow
As part thickness increases, the contrast on the film will _____ because of the production of scattered radiation.decrease
Which of the following determine the quality of the x-ray beam? (a. filtration, b. grid ratio, c. kilovoltage)a, c (filtration and kilovoltage)
Low KV, _____ wavelength, _____ penetrationlong; low/decreases
High KV, _____ wavelength, _____ penetrationshort; high/increases
Any primary radiation that changes direction and/or speed is called _____ radiationscattered
An increase in scattered radiation on the film results in _____ in contrastdecrease
A decrease in kilovoltage will result in a(n): _____ in penetration, _____ in wavelength, _____ in scattered radiation, _____ in fog, _____ in density, _____ in contrast (increase/decrease)decrease; increase; decrease; decrease; decrease; increase
A _____ of contrast consists of numerous shades of white, grey and black (mostly grey)long scale
A _____ of contrast consists of few shades of grey, mostly black and white imageshort scale
Control that adjusts image contrast of the digital imagewindow width
Decreases the range of densities displayed in the image (few shades of grey), increases contrast (more black and white)narrow window width/high contrast
Increases the range of densities displayed in the image (many shades of grey), reduces contrast (less black and white)wide window width/low contrast
Sources of image foglight, radiation, age, chemical processing, heat/high temperature, darkroom safelight
Image fog first appears in the _____ of the H&D curve, which are the white/lighter areas of the imagetoe/lower portion

Increasing/Decreasing KV

Question Answer
Beam penetration power increasesIncrease KV
Wavelength decreases (becomes shorter)Increase KV
Image density increasesIncrease KV
Image contrast decreases (more grey shades)Increase KV
Amount of scatter radiation increasesIncrease KV
Image fog increasesIncrease KV
Exposure latitude margin of error increasesIncrease KV
Beam penetration power decreasesDecrease KV
Wavelength increases (becomes longer)Decrease KV
Image density decreasesDecrease KV
Image contrast increases (more black and white shades)Decrease KV
Amount of scatter radiation decreasesDecrease KV
Image fog decreasesDecrease KV
Exposure latitude margin of error decreasesDecrease KV

Filtration and Compensating Filters

Question Answer
Filtration provided by the x-ray tube glass is referred to as _____inherent filtration
Total tube filtration must be at least _____mm of aluminum/equivalent2.5
A filter placed in the path of the x-ray beam to provide uniform density on the radiograph is called a(n) _____compensating filter
Most radiography filters are made of _____aluminum
A wedge filter would be placed above the part so that the thickest part of the filter is above the _____ body partthinnest
Radiography filters (added filtration) are placed between the _____BLD and x-ray tube/collimator and x-ray tube
Any added filtration above 2.5mm Al/equivalent will _____ contrast because it also _____ densitydecrease; decreases
Must have at least 2.5mm Al filtration if operating the tube above _____70 KV

Contrast and Filtration

Question Answer
Which of the following situations will produce the most contrast? (a. part made of organs only, b. part made of gas and bone)b. part made of gas and bone
A sheet of aluminum placed in the path of the x-ray beam to reduce patient exposure is called a _____filter
As the amount of scattered radiation reaching the film increases, the amount of fog produced _____increases
The greatest enemy of contrast is _____scattered radiation
A radiograph made up of many shades of grey is referred to as having _____ scale contrastlong
A film with a short scale of contrast would most likely be produced with _____ kilovoltagelow
Which of the following would be used when the body part varies greatly in thickness or tissue composition? (a. Al filters, b. compensating filters, c. grid, d. none of the above)b. compensating filters

Film Contrast

Question Answer
Which of the following produces the most contrast? (a. cardboard holder, b. slow speed screen, c. par speed screen, d. rare earth screen)d. rare earth screen (faster the speed, better the contrast)
An increase in processor developer temperature will _____ radiographic fog, which results in a(n) _____ in contrastincrease; decrease
A decrease in contrast results in a film with _____many shades of grey
To limit the amount of scattered radiation on the film, which of the following would be used? (a. collimator, b. cone, c. grid)a, b, and c - All three of them (cone, grid and collimator)
A film with a short latitude range would be produced with _____low KV
Which of the following would alter contrast? (a. grid, b. intensifying screen speed, c. BLD's, d. kilovoltage)a, b, c, d - All four of them (grid, intensifying screen speed, BLD's, kilovoltage)
If I use a 16:1 grid instead of a 10:1 grid, increase my exposure factors to produce sufficient density, the resulting constrast will _____increase
A compensating filter is used to provide _____more uniform film density
X-ray beam quality is determined by _____ and _____KVP and filtration
Inherent ability of screen/film emulsion to react to radiation and record a range of image densitiesscreen/film image receptor contrast
Factors of screen/film image receptor contrastreceptors, processing, grids, BLDs
Must remain constant during processing to maintain consistent quality of a screen/film image time, temperature, activity of developer
Device used to reduce the production of scatter radiation, and improve image contrastbeam limiting device (BLD)/beam restrictor/collimation
Prevent scatter radiation from reaching the image receptor and increase image contrastradiographic grid

Film Contrast and Latitude

Question Answer
Visible density range is compressed into a narrower exposure rangehigh contrast/narrow latitude
Screen/film capable of only recording black and white shades in the imagehigh contrast/narrow latitude
Low KVP - 40-70 KV rangehigh contrast/narrow latitude
Steeper slope on the H&D curvehigh contrast/narrow latitude
Margin of error in setting a technique/mAs is narrow. mAs must be exact to produce an acceptable radiographic imagehigh contrast/narrow latitude
Used for extremity examshigh contrast/narrow latitude
Visible density range is expanded across a wider exposure rangelow contrast/wide latitude
Screen/film capable of recording many shades of black, white and grey in the imagelow contrast/wide latitude
High KVP - 80-120 KV rangelow contrast/wide latitude
Flatter H&D curvelow contrast/wide latitude
Margin of error in setting technique/mAs is wide (large). mAs can be off and still can produce an acceptable radiographic imagelow contrast/wide latitude
Used for chest examslow contrast/wide latitude

Digital Image Contrast

Question Answer
Determined by a processing algorithm (computer program) to provide the desired image appearancedigital image contrast/display contrast
Digital image receptors have a _____ response to exposurelinear
Increase in the number of shades of grey available to display on a digital image _____ the contrast resolutionincreases/improves
Increased contrast resolution increases the visibility of _____ in the digital imagerecorded detail/spatial resolution
Range of exposures that may be captured by a detector. Much wider for digital imaging than screen/filmdynamic range
Factors that affect digital image contrastkilovoltage, scatter radiation, radiographic grids, BLDs
If the x-ray exposure field is not properly collimated, sized and positioned in digital imaging, _____ errors may occurexposure field recognition
Result of exposure field recognition errors in a digital imagevery dark, very light, or very noisy