Radiology Flashcards
radiology absorption
varying amounts of absorption of X-Rays by the tissue determines what the radiograph will look like
more absorption, less x-rays get to film means…
…image looks whiter (for instance bone)
less absorption, more x-rays get to film means…
…image looks blacker (for instance lungs-air)
radiograph
“X-Ray”
- a stream of photons are passed through a portion of the body
- the photons will be absorbed or pass through the various tissues
- photons which pass through expose the radiographic film
factors that affect absorption of X-Rays by the tissues
atomic number and thickness of tissue
___atomic number absorbs more
higher
___tissues absorbes more than ___structures
thicker absorbs more than thinner structures
effective atomic number of bone
11-12
effective atomic number of soft tissue and muscle
7-8
effective atomic number of fat
6-7
effective atomic number of gas
1-2
radiopaque
white (i.e. metal, bone)
radiolucent
black (i.e. air in lungs)
basic tissue desnisites (largest to smallest)
bone density>
soft tissue density>
fat density>
gas density
why is contrast media used
to improve visualization in certain cases