Ch5 Other Modalities Flashcards
The feature of a radiographic image that affects the clinician’s ability to see details and detect lesions
contrast
Quality inherent in the film type and the processing techniques that is not changeable by the operator
film/detector contrast
Physically similar to x-rays, but are generated spontaneously from the decay of radioactive isotopes
gamma rays
The “hole” in the center of the CT scanner
gantry
Numeric scale for representing different tissue characteristic by their x-ray density (or “electron density)
Hounsfield unit
Radiopaque medium used in imaging; iodine and barium are examples
positive contrast agent
Affected by the absorption characteristics of the tissue being imaged and the imaging parameters
subject contrast
Tube that is placed by a neurosurgeon to relieve intracranial pressure due to increased cerebrospinal fluid (hydrocephalus)
ventriculoperitoneal shunt
List 4 important characteristic of x-rays
- X-ray have no mass 2. travel at the speed light 3. can penetrate matter 4.invisible to human eye 5. electrically neutral
Tissues that absorb a greater quantity of the x-ray appear _____ on the x-ray image
white
The _____ areas on an x-rays image indicate areas of lower density.
black
Air absorbs the beam ______ and is displayed as black
least
The difference between adjacent densities or structures is called ______
contrast
Which radiograph is a good example of high contrast?
chest x-ray
Name two contrast media that are used in radiography
barium, iodine
