The flashcards below were created by user
johndc3476
on FreezingBlue Flashcards.
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What is vignetting?
When the center of the image intensifier screen has better resolution, a brighter image and less geometric distortion
Also known as pincussion distortionIts a fall-off in brightness at periphery of an image
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What is quantum mottle?
Quantum mottle is a blotchy or grainy apperance caused by insufficient radidation to create a uniform image
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How do you fix quantum mottle?
Increase mA
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What is mirror optics?
It's a viewing system with a series of lensers and mirrors that magnify and reflect the image to a viewer.
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What are the problems that mirror optics have?
Loss of image brightness and only one person can see it at a time.
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What is the video system?
It is the most common viewing system that has a closed circuit unit wit hall transmission through cable to avoid broadcast interference.
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How does information get across with a videosystem?
Light from output screen converted into electronic signal -> signal sent to video monitor.
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What are the two types of video camera tubes used for fluorscopy?
television tube and cathode ray tube
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What do television and cathode ray tubes consist of?
A vacuum tube with fluoresecnet phosphors coated on the inside of the front screen as well as an electron gun with deflecting and focusing magnets.
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How does the monitor create an image?
It creates the image as the electron gun sprays the pulsed stream of electron for the video camera onto the phosphor screen.
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How many lines per second can electron beams scan?
525 hrorriziontal line per 1/30 of a second
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What does a cine consist of? What are the two formats they come in?
Has a movice camera positioned to intercept image produced by output screen16mm and 35 mm formats
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Whats a the good and bad about cine?
Greater resolution than video systems but MORE patient dose.
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What fluorsocopic image recording method cause the most patient dose?
Spot filming
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What are some benefits of digital recording?
Beneficial because you have post processing manipulation, storage and sharing
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For patient radiation protection, what is the maximum TABLE TOP exposure rate and should not pass?
10 R/min
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What is the minimum SOD for mobile an fixed equipment?
- Mobile = 12 inches
- Fixed equipment = 15 inch
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How much exposure should a patient approximately receive?
7.2 R/min
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For every 1000 photons reaching the patient, how much scatter is there? How much of the scatter reach the image detector?
- 100- 200 scatter radiation
- 20 scatter reach the image receptor.
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Highest amount of scatter occurs at what angle of the incident beam?
90 degrees
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What can you do that may help reduce patient exposure?
- Use largest field of view
- Collimate are of interest whne possible
- Use highest acceptable kvp
- Use low dose modes if available
- Use pulsed flouroscopy if aailable.
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What is the main source for staff radiation when in a flouro room?
Scatter radiation from the patient.
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