Image acquisition and evaluation review
Help!
|
|
||||
|---|---|---|---|---|---|
| Density (brightness) | amount of blackness on a given area of a radiograph
🗑
|
||||
| mAs controls what? | quantity of xrays produced
🗑
|
||||
| kVp controls what? | the energy or quality of xrays produced
🗑
|
||||
| Contrast | differences in adjacent densities on the radiographic image
🗑
|
||||
| density may be defined as: | darkness on a radiograph
🗑
|
||||
| the radiographic image is formed by: | exit rays striking the image receptor
🗑
|
||||
| the primary controlling factors of density are: | mAs and window level
🗑
|
||||
| How do you describe the relationship between mAs and density? | density is directly proportional to mAs
🗑
|
||||
| the number of electrons boiled off the cathode and consequently the number of xrays produced are controlled by: | mAs
🗑
|
||||
| the law stating that any combinations of mA and time that produce the same mAs value will produce the same radiographic density is the: | reciprocity law
🗑
|
||||
| the active portion of a CR IP is: | PSP
🗑
|
||||
| the primary controlling factors of contrast are: | kVp and window width
🗑
|
||||
| the relationship between kVp and density may be described as: | direct, although not proportional
🗑
|
||||
| the 15% rule states that: | density may be halved be decreasing kVp by 15%
🗑
|
||||
| what governs the relationship between SID and density? | inverse square law
🗑
|
||||
| if SID is doubled, what may be said about radiographic density? | density is reduced to one-fourth
🗑
|
||||
| if SID is reduced by one-half, what must done to mAs to maintain a constant density? | reduce mAs to one-fourth its original value
🗑
|
||||
| What can cause poor recorded detail? | Long OID, Large focal spot, patient motion, magnification
🗑
|
||||
| in digital fluoroscopy, what equipment should be used to view the image? | high-resolution monitor capable of displaying millions of pixels
🗑
|
||||
| a primary advantage to digital fluoroscopy is: | postprocessing manipulation of the image
🗑
|
||||
| which of the following describes the relationship between radiographic density and the use of grids? | grids reduce density unless mAs is increased to compensate
🗑
|
||||
| the use of filtration: | has little effect on density because xrays removed from beam are not image producing rays
🗑
|
||||
| as beam restriction increase: | density decrease
🗑
|
||||
| the variation of xray intensity along the longitudinal axis of the xray beam describes: | anode heel effect
🗑
|
||||
| the thicker part of anatomy should be placed under which aspect of the xray tube? | cathode
🗑
|
||||
| the function of contrast is to: | make detail visible
🗑
|
||||
| a radiograph with few gray tones, primarily exhibiting black and white, would be described as having what type of contrast? | high contrast, short scale
🗑
|
||||
| poorer recorded detail may be caused by which of the following factors? | pixel pitch wide
🗑
|
||||
| high kVp produces which of the following? | low contrast, long scale, many gray tones
🗑
|
||||
| low kVp produces which of the following? | high contrast, short scale, few gray tones
🗑
|
||||
| more uniform penetration of anatomical structures occurs when what level of kVp is used? | high
🗑
|
||||
| differential absorption of the xray beam is a function of: | photoelectric interaction
🗑
|
||||
| What effect does beam restriction have on contrast? | increase contrast because of reduction in the number of compton interactions that occur
🗑
|
||||
| the adjustment in technical factors required when using beam restriction is: | increase mAs to compensate for the number of rays removed from the primary beam
🗑
|
||||
| what effect does the use of radiographic grids have on contrast? | increase contrast
🗑
|
||||
| as the amount of beam filtration is increased: | contrast decreases
🗑
|
||||
| the portion of contrast that is caused by variations in the anatomy or is secondary to pathological changes is called: | subject contrast
🗑
|
||||
| recorded detail is: | geometric representation of the part being radiographed
🗑
|
||||
| better recorded detail may be caused by what? | long SID, short OID, small focal spot
🗑
|
||||
| optimal recorded detail may be created using what? | narrow pixel pitch
🗑
|
||||
| elongation and foreshortening are examples of: | shape distortion
🗑
|
||||
| magnification is caused by: | short SID, long OID
🗑
|
||||
| distortion that occurs when the xray beam is angled against the long axis of a part is: | foreshortening
🗑
|
||||
| distortion that occurs when the xray beam is angled along the long axis of a part is: | elongation
🗑
|
||||
| the actual patient dose as measured by a meter embedded in the collimator is: | dose area product (DAP)
🗑
|
||||
| quality assurance and maintenance of CR cassettes includes cleaning and inspecting the plates at least: | every 3 months
🗑
|
||||
| quality assurance and maintenance of CR cassettes includes erasing plates at least: | daily
🗑
|
||||
| quality assurance of digital imaging requires the uniformity of processing codes to ensure: | image appearance consistency
🗑
|
||||
| a software function that evens the brightness displayed in the image called: | smoothing
🗑
|
||||
| beam part receptor alignment latitude describes: | the latitude of collimation that still allows the software to detect collimated edges
🗑
|
||||
| exposure technique in digital imaging may be adjusted by: | increasing kVp
🗑
|
||||
| digital imaging is more sensitive to: | scatter and background radiation
🗑
|
||||
| inappropriate collimation causes: | histogram analysis error
🗑
|
||||
| an artificial increase in display contrast at an edge of the image is: | edge enhancement
🗑
|
||||
| as speed class increases: | the likelihood of noise increases
🗑
|
||||
| smoothing software may result in: | loss of fine detail
🗑
|
||||
| excessive processing of the digital image may: | degrade visibility of anatomy
🗑
|
||||
| a high SNR provides an image with: | higher spatial resolution
🗑
|
||||
| quantum noise limits ability to see: | detail
🗑
|
||||
| grid ratio is defined as: | the ratio of the height of the lead strips over the distance between the lead strips
🗑
|
||||
| grid frequency is defined as: | the amount of lead in the grid (expressed as the # of lead strips per inch)
🗑
|
||||
| a grid with lead strips and aluminum interspacers that are angled to coincide with the divergence of the xray beam is called a: | focused grid
🗑
|
||||
| the range of SIDs that may be used with a focused grid is called: | grid radius
🗑
|
||||
| the best scatter cleanup is achieved with the use of: | crosshatch grids
🗑
|
||||
| grid cutoff may be described as: | decreased density on a radiograph as a result of absorption of image forming rays
🗑
|
||||
| use of the air gap technique: | works because scatter radiation travels in divergent paths and misses the IR as a result of increased OID
🗑
|
||||
| materials that make flat panel detectors possible are: | amorphous silicon
🗑
|
||||
| Which of the following maintains image brightness over a wide range of exposures? | automatic rescaling
🗑
|
||||
| the available gray scale of an imaging system is determined by: | bit depth
🗑
|
||||
| the smallest exposure change able to be captured by a detector is called: | contrast resolution
🗑
|
||||
| an indicator of the dose level needed to acquire an optimal image is: | dose area product
🗑
|
||||
| the useful image acquisition area of an image receptor is: | detector size
🗑
|
||||
| the smallest resolvable area in a digital imaging device is: | detector element
🗑
|
||||
| what allows more anatomical structures to be captured during an exposure? | dynamic range
🗑
|
||||
| the range of receptor exposures that provides a quality image is called: | exposure latitude
🗑
|
||||
| which of the following is a graphical representation of pixel values? | histogram
🗑
|
||||
| undesirable fluctuations in brightness are called: | image noise
🗑
|
||||
| the number of pixels making up the digital image is the: | matrix size
🗑
|
||||
| the expression of image quality provided by a detector is called: | modulation transfer function (MTF)
🗑
|
||||
| which of the following terms describes the highest spatial frequency that can be recorded by a digital detector? | nyquist frequency
🗑
|
||||
| what converts light into a charge? | photodiode
🗑
|
||||
| the smallest area represented in a digital image is the: | pixel
🗑
|
||||
| the number of pixels/mm in an image is called: | pixel density
🗑
|
||||
| the space from the center of a pixel to the center of the adjacent pixel is called: | pixel pitch
🗑
|
||||
| the process of assigning a value to each pixel to represent a gray tone is called: | quantization
🗑
|
||||
| a material that absorbs xray energy and emits part of that energy as visible light is called: | scintillator
🗑
|
||||
| bit depth is equal to: | 2n (n equals the # of bits)
🗑
|
||||
| receptor exposure | the amount of radiation striking the image receptor
🗑
|
||||
| 30% rule | to see a difference in density, the mAs must change at least 30%
🗑
|
||||
| filtration effect on contrast? | increase filtration=lower contrast
🗑
|
||||
| collimation effect on contrast? | increase collimation=increase contrast
🗑
|
||||
| units of spatial resolution? | lines pairs per millimeter (lp/mm)
🗑
|
||||
| what technical factors should be used for wet plaster casts? | increase 15 kVp
🗑
|
||||
| what technical factors should be used for dry plaster casts? | increase 10 kVp
🗑
|
||||
| what technical factors should be used for fiberglass cast? | increase 5 kVp
🗑
|
||||
| what technical factors should be used for iodinated contrast? | not over 70 kVp
🗑
|
||||
| what technical factors should be used for barium contrast? | not over 100 kVp
🗑
|
||||
| whats the order of film development? | developer, fixer, wash, dry
🗑
|
||||
| where do most processor problems with film occur? | developer
🗑
|
||||
| what temperature should the developer be? | +/- 2 degrees of 95 F/ 35 C
🗑
|
||||
| the faster the speed of the screen? | the greater the density
🗑
|
||||
| where is the micro switch located that controls replenishment | near the entrance roller
🗑
|
||||
| collimation effect on density? | increase collimation=decrease in density
🗑
|
||||
| how high is the safelight over the processor | 36"
🗑
|
||||
| does mAs go up or down for a higher grid ratio? | mAs goes up
🗑
|
||||
| mAs effect on density? | increase mAs=increase density
🗑
|
||||
| kVp effect on density? | increase kVp=increase density
🗑
|
||||
| SID effect on density? | increase SID=decrease density
🗑
|
||||
| grid ratio effect on density? | increase grid ratio=decrease density
🗑
|
||||
| filitration effect on density? | increase filitration=decrease density
🗑
|
||||
| anode heel effect on density? | increase anode heel effect=decrease density
🗑
|
||||
| patient factors effect on density? | increase factors=decrease density
🗑
|
||||
| kVp effect on contrast? | increase kvp=decrease contrast
🗑
|
||||
| OID effect on contrast? | increase OID=increase contrast
🗑
|
||||
| grid ratio effect on contrast? | increase grid ratio=increase contrast
🗑
|
||||
| patient factors on contrast? | increase factors=decrease contrast
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
Chrslarsen
Popular Radiology sets