RAD 106
Describe indirect capture DR in flat panel acquisition.
1. absorbs x-rays, converts to light
2. converts light to electric signal
3. computer processes electric signal
4. viewed on computer monitor.
How will the histogram appear with Low KVP:
Wider.
What is signal to noise ratio's effect on resolution?
Higher signal to noise ratio leads to better resolution on the image
What happens the more you manipulate an image?
you lose detail/quality of the image.
What is: in digital imaging, manipulates pixels when exposure is greater than what is needed on an image. This fixes high techniques.
Auto-scaling.
Describe direct capture DR in flat panel acquisition.
1. photoconductor absorbs x-rays
2. signal collected, produces electrical signal
3. signal sent to computer for processing
4. image viewed on computer screen.
What is: images are produced with uniform brightness and contrast, regardless of the amount of exposure used to acquire the image?
Automatic rescaling.
What is: a type of electrical noise, in reference to our equipment. An artifact that is created through digital imaging if things are not in alignment?
Aliasing.
what does window level do?
controls how bright or dark the screen image is.
What is: Phenomenon in digital imaging, where techs are increasing the mAs to avoid an underexposed image.
Dose creep.
What is; some flat panel systems take images faster than the detector can accommodate?
image lag
What is: When frequencies of areas of interest are known, those frequencies can be amplified and other frequencies depressed. This increases contrast and edge enhancement.
High Pass Filtering.
What is required in Cr to acquire/capture an image?
The phosphor plate.
What would contrast look like if pixel depth is low?
Gives you low contrast, and will not be able to see many shades of gray.
low pixel sampling will lead to what?
low resolution.
How can you decrease image lag?
1. Do exposure with highest technique last.
2. reduce time between exposures
3. collimate as closely as possible
4. use appropriate technical factors
What is: When anatomy or the area of interest is to large to fit on one cassette, multiple images can be stitched together using specialized software program?
Stitching.
A low EI or S number means the exposure is _______?
High. they have an inverse relationship
What does the optical mirror do?
How will the histogram appear with High KVP?
Narrow
What is: a type of spatial frequency filtering, sometimes refered to as "smoothing". Occurs by averaging each pixel frequency with surrounding pixel values to remove high frequency noise. Useful for viewing fine bone tissue?
Low Pass Filtering.
you lose less information
What has better spatial resolution, CR or screen-film?
Screen-Film.