Computed Radiography Test
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
|
|
||||
|---|---|---|---|---|---|
| voxel | 3D pixel
🗑
|
||||
| IRD | image reader device-reads latent image on CR cassette
🗑
|
||||
| what are some other terms for CR | *indirect capture
*cassette-based
*film-less
🗑
|
||||
| what is the process of latent image acquisition | *x radiation ionizes europium sites causing them to release free eletrons
*free electrons are moved to a higher energy band called F center
*F center holds electrons in bound state
*# of trapped electrons is equal to absorbed radiation
🗑
|
||||
| nyquist frequency | *determines the maximum spatial resolution for a given sampling frequency by IRD
*states that if the desired spatial resolution is (x) the sampling frequency must be 2(x)
-increasing the sampling frequency increases the time it takes to display an image
🗑
|
||||
| needle/columnar phosphor | phosphor crystals arranged as needles or columns
🗑
|
||||
| turbid phosphor | phosphor crystals distributed throughout a phosphor layer
🗑
|
||||
| europium | *impurity that allows luminescence *has ecxess electrons at ground level *activator *storage property
🗑
|
||||
| when should you use a grid | *kVp higher than 60
*whent the part being xrayed is at least 12cm thick
🗑
|
||||
| radiopaque | cannot be penetrated by xrays
🗑
|
||||
| radioluscent | easily penetrated by xrays
🗑
|
||||
| dicocm header | *header with pt name and medical record number, and other pt info, that cannot be edited by RT
🗑
|
||||
| artifact | any unwanted density
🗑
|
||||
| what are the different types of ADC in the IRD | *photomultiplier tube
*photodiode
*CCD
🗑
|
||||
| what is the relationship between scanning freq. and contrast and resolution | the higher the scanning frequency, the higer the contrast and resolution
🗑
|
||||
| how do you change brightness and contrast in CR | *use window and level/width
*ROI box
🗑
|
||||
| ROI | range/region of interest-box shaped area of an anatomic structure on a reconstructed digital image defined by the operator by moving the cursor
🗑
|
||||
| MTF | modulation transfer function- measure of the quality of a detector system, determined by the systems contrast and spatial resolution quality
🗑
|
||||
| banding | *frequency of scan does not meet grid frequency
-can be prevented by using appropriate grid
🗑
|
||||
| flat panel artifacts | *dust/dirt
*scratches
*pixel malfunction
*gost images
🗑
|
||||
| software artifacts | *inorrect histogram
*auto-rescaling not working
*image too compressed
🗑
|
||||
| subject artifacts | *piercings on pt
*any metal or artifacts on pt
*collimation off
🗑
|
||||
| speed class | *CR image acquisition operation that affects certain factors
🗑
|
||||
| when should you erase xray plates | *unsure of what is on them
*hasnt been used in 48 hrs
*erase twice if double exposed or used on large pt
🗑
|
||||
| how long after exposure should you process an imaging plate | *within 1hr to avoid degeneration
-latent image loses 25% of its energy within 8hrs
🗑
|
||||
| what will happen if you turn tube with grid | you will get grid lines
🗑
|
||||
| which way is the correct way to place your cassette | *blue line down if lengthwise
*blue line to your right if crosswise
🗑
|
||||
| what are the layers of a CR cassette | *backside *antistatic/backing layer *base *reflective/anti-halo layer *phosphor layer *protective coat/layer
🗑
|
||||
| what is the backside of the cassete made of | lead, also contains lead foil on the inside
🗑
|
||||
| antistatic/backing layer | *mounted to the back of cassette *prevents handling artifacts *contains barcode *prevents static energy
🗑
|
||||
| reflective/anti-halo layer | *prevents laser light from bouncing back and causing fog or noise *anti-halo is blue *reflective is white
🗑
|
||||
| phosphor/active layer | *acquires latent image
🗑
|
||||
| protective layer/overcoat | *toward tube *prevents handling artifacts *allows cleaning
🗑
|
||||
| what is the material that is on the outer covering(tube side) made of | carbon or bakelite
🗑
|
||||
| what are the two ways that phosphor crystals are aranged in a psp plate | *needle/columnar *turbid
🗑
|
||||
| what does speed class affect | *exposure index *auto-rescaling *image appearance -the slower the speed the better the contrast
🗑
|
||||
| what is the purpose to the exposure index | to tell the range of exposures that are acceptable
🗑
|
||||
| what is the first step in the conversion of a latent image to manifest image in the IRD | *there is an initial low level laser scan that sets boundries for collimation of the image and test to make sure latent image matches histogram selected before setting aut-rescaling
🗑
|
||||
| what is the second step in the conversion of a latent image to manifest image in the IRD | *high level lase scan to release trapped electrons from f center and back into their regular state, causing emision of light
🗑
|
||||
| what is the third step in the conversion of a latent image to manifest image in the IRD | *light is captured by CCD, which converts it to an electronic signal
🗑
|
||||
| what controls contrast resolution | *dynamic range *quantization
🗑
|
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:
bigad1982
Popular Radiology sets