Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
22 Cards in this Set
- Front
- Back
|
reduction in the total number of xray photons remaining in the beam after passing through a given thickness of material (patient tissue)
|
attenuation
|
|
|
what happens to the primary beam after it leaves the tube
|
-some photons are absorbed (photoelectric absorption)
-some photons scatter (Compton interaction) -some photons pass through the tissue to the IR -primary beam from target to IR is reduced in intensity (beam has been attenuated, patient attenuates the beam) |
|
|
___ atomic numbers attenuate more than ___ atomic numbers
|
high, low
|
|
|
atomic number of barium
|
56
|
|
|
atomic number of calcium
|
20
|
|
|
atomic number of lead
|
82
|
|
|
atomic number of iodine
|
53
|
|
|
atomic number of hydrogen
|
1
|
|
|
atomic number of carbon
|
6
|
|
|
atomic number of oxygen
|
8
|
|
|
roughly the the average of the atomic numbers of the elements contained within a substance such as air or bone
|
effective atomic number
|
|
|
what is a factor that affects attenuation
|
density of absorbing material (quantity of matter per unit or volume measured in kilograms per cubic meter) kg/m to the third power
|
|
|
what is the densest tissue we image
|
bone
|
|
|
what is the lightest tissue we image
|
air
|
|
|
if effective atomic number goes up, density goes up, so attenuation goes
|
up
|
|
|
increased thickness will absorb ____
|
more
|
|
|
subject= what??
|
patient (subject density, contrast, detail, distortion)
|
|
|
thicker and denser body parts absorb ____ radiation, that means there is ___ exposure to the IR
|
more, less (lighter shades of grey) ex. liver and bone
|
|
|
thinner and less dense body parts absorb ____ radiation, so _____ exposure to the IR
|
less, more (darker shades of gray) ex. air and gas
|
|
|
different shades of gray, allows us to see different bits of anatomy
|
contrast
|
|
|
sharpness, resolution
|
detail
|
|
|
expectation of seeing anatomy in each image in a certain way, incorrect positioning leads to, ROI far away from IR leads to magnification
|
distortion
|
