Lesson 1 Flashcards
the key to diagnosis
precision
defines the path to healing
clarity of an image
important for proper diagnosis
Optimum Quality Radiographic Image
Image on the radiograph is a result of:
Xray that are absorb
Xray that are scattered
Xray that pass through matter without interaction
the radiograph are the result of x-ray photons that
interact with the film.
Black areas
on the radiograph are areas that received no exposure.
White areas
are caused by partial exposure from x-rays.
Gray tones
Uses xray film and IS in image formation
Film screen imaging system
Film is placed between two IS.
Film screen imaging system
The remnant X-ray struck the screen and converts this to light which exposes the film.
Film screen imaging system
Film is then chemically processed so image appears and becomes permanent on the film.
Film screen imaging system
Film is viewed using a negatoscope for interpretation.
Film screen imaging system
Uses computers to produce an image.
Digital imaging system
Two types of digital imaging system
Computed radiography
Digital radiography
Properties of radiographic image
Density
Detail
Distortion
Contrast
Mottle
Noise
Amount of blackening on the radiograph.
Density
Relates directly to the amount of exposure received by the film.
Density
The blacker the film, the higher the
Density
Density difference between adjacent areas on the radiograph.
Contrast
Results from differences in attenuation of the x-ray beam as it passes through various tissues in the body.
Contrast
Refers to how well one can see small structures on the radiograph.
Detail
Sharpness of the structural edges of the radiograph (definition).
Detail
Change in size and/or shape of the object as seen on the radiograph.
Distortion
Two types of distortion
- Size distortion (magnification)
- Shape distortion ( true distortion)
The apparent granular appearance in areas of apparent even density in the radiographic image.
Mottle
Three types of mottle
- Film graininess
- Structure mottle
- Quantum mottle
random fluctuation in the density of the image usually inherent in the system.
Noise
something that detracts the viewer from seeing the true image (signal).
Noise
Four sources of noise
- Film graininess
- Structure mottle
- Quantum mottle
- Scatter radiation
