The II and the eye Flashcards
During conventional fluoro systems: Once light leaves the output phosphor it is coupled to a TV camera system through either:
- Fiber optic cable
(old system) - Lens Coupling
Name 2 characteristics of Fiber optic cables
- compact
2. Durable
Name characteristics of the lens optic coupling
- Large
- Fragile
- Has beam splitting mirror
____ are images taken to document a patient’s anatomy at specific moments during the exam
spot films
What is the purpose of a beam splitting mirror
Allows 10 % of light beam to go to TV camera
and 90% of light beam to the ancillary film camera
List the 4 main components of cinefluorography
- Synchronization
- Framing frequency
- F-number of the optical system
- Framing and patient radiation dose
___ is the number of frames per second (f/s).
framing frequency
____ is the focal length/lens diameter
F-number
( lower the f # , the more light will reach imaging plane and faster the lens) = less exposure to the patient
Why must the x-ray beam be restricted to match the framing method
area of the pt. are exposed but the image is never recorded
What type of framing should be avoided
underframing:
Fluoro image < frame
Which framing results in no part of image being lost by 58% of film is used
Exact framing:
Diameter of the intensifier image & the smallest dimension of the cine frame are the same
Which framing results in part of the image is lost
Overframing
Which framing results in all of the film being used but 39% of image is wasted
Total overframing
What is a disadvantage of video tape recording
Video does not exhibit high resolution
What does ABS stand for and what does it do
Automatic brightness stabilizer
aka: ABC
____ converts the light signal from output phosphor to an electronic signal
CCD or television camera tube
name the 3 types of tv camera tube
- Vidicon= most common
- Plumbicon
- Orthicon
What is the weakest link in the imaging chain?
TV monitor
What is the purpose of the tv monitor
it is a cathode ray tube
it controls brightness / contract
most fluoro tv systems use ____, regardless of the monitor size
525 raster pattern
What technique factor is used to control quantum mottle in fluoroscopy
kVp
Name the factors that affect image quality
Quantum Mottle
- Contrast
- Resolution
- Distortion size/shape/image
- Vignetting
- Veiling glare
- Lag
Name the 2 types of distortion
size distortion
shape distortion
