Image Contrast Flashcards
The CHEST has LOW or HIGH inherent radiographic contrast?
HIGH
The bones of the thorax are very dense, with medium density soft tissue structures (hear and mediastinum) and low density (air filled lungs)
The ABDOMEN has LOW or HIGH inherent radiographic contrast?
LOW
Kidneys, spleen, muscle, fat and bowel are all similar density.
There is a small amount of bone (spine/pelvis) and Bowel gas too
The QUALITY of the beam means?
the energy of the beam (set by kVp)
Define IMAGE CONTRAST
The difference in brightness on the visible image between adjacent structures
Define RADIOGRAPHIC CONTRAST
The difference in brightness on the radiograph between adjacent structures
Define INHERENT PHYSICAL CONTRAST
A physical difference between two structures which can be used to separate them (either atomic number or density)
Define BRIGHTNESS
the luminance of an image (or area of an image) - used when viewing radiographs on screen
Define DENSITY
the blackness of of an image (or area of an image) - used when viewing radiographs on a light box
To make an image more grey
Increase Kv
To make an image more contrasty
Decrease Kv
To make an image more black and white
Decrease Kv
To make an image less contrasty
Increase Kv
To increase the contrast of the on screen image
Increase G-value
To increase the brightness of the on screen image
Decrease S-value
Define greyscale
different intensities between white and black
