Radiology Physics Flashcards
what is the purpose of the anode?
rotate to dissipate heat
convert electrons to x-rays
what is the purpose of the aluminum filter at the bottom of the x-ray tube?
absorb low levels of radiation
what is the cable that comes out of the x-ray tube that has a negative charge?
cathode
what is the cable that comes out of the x-ray tube that has a positive charge?
anode
what is the function of the anode filament?
convert electrons to x-ray photons
what is the anode made of?
molybdenum or tungsten
why do the electrons travel from cathode to anode?
large difference in voltage between the two
what makes the vacuum tube so that obstructions are removed from the electrons reaching the anode?
glass tube
silicon dioxide
what is x-ray photon attenuation?
reduction in intensity as the electron traverses the matter
caused by absorption or deflection
what are the factors that affect x-ray attenuation?
thickness of tissue
different tissues
effective atomic number
physical density of body tissues
x-ray tube kilovoltage employed
x-ray filtration
what is the kVp?
peak voltage
max high voltage applied
the higher the mA, the _______ the amount of electrons
higher
what do x-rays hitting the detector cause?
exposure: black
when orienting a radiograph of lateral recumbency, which direction should the head be?
to your left
when orienting a radiograph of VD/DV, which direction should the apex of the heart be pointing?
to your right
right side of animal to your left
how does magnification occur?
if one object is closer to the x-ray tube, it will appear larger in comparison to one that is further away
what is distortion?
uneven magnification
foreshortened femur on radiograph
what is the summation effect?
when objects are superimposed, the final opacity is the result of the total x-ray absorption by all superimposed objects
what is the silhouette effect?
when two structures of the same radiopacity are in contact, their margins cannot be distinguished
why are two views at a 90 degree angle needed?
depth perception
what is bremsstrahlung?
electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle
what does the window layer do?
provides vacuum seal and protects components
what is mAs?
mA: tube current
s: how long the mA will last
(mA) x (s)
what does higher mAs mean?
higher amount x-rays
darker image
if there is an x-ray with a bone that is more radiopaque, how do you say this?
increased area of bone density
increased bone or mineral opacity
