prime factors Rad Science Flashcards
factors affecting x-ray emission under direct control of the radiographer are the prime factors
mAs
kV
distance
measure of number of photons in the beam
quantity
quantity is also known as
output
intensity
exposure
density
units of measurements Trad= R=Ionization in air = RAD= absorbed dose = REM= occupational dose = Curie= radioactive decay =
SI coulmbs/kg Gy SV BQ
factors that directly affect quantity
mAs
kV
distance (SID)
filtration
thickness of material needed to attenuate 50% of primary beam
1/2 value layer
measurement of the penetrating ability of the beam (describes the distance an x-ray beam travels in matter)
quality
quality is numerically represented by the
1/2 value layer
factors that directly affect x-ray quality are
kV & filtration
filtration= 1/2 value layer & beam hardening
measurement of x-ray tube current (the # of electrons crossing form cathode to anode per sec.)
mAs
_ is directly proportional to tube current
mA
the # of x-rays created at the target is a product of the electrons crossing the tube and how long the electrons are allowed to cross is what law
(mA x s) reciprocity law
mAs is the primary controller of
film density
increasing _ will caude an increase in the speed and energy of the electrons applied across the tube
kV
what affects the quantity because more interactions occur at the target when kV increases
kV
kV affects the _ of the beam because each electron has more energy (greater penetrability)
quality
increasing kV by _ will cause a boubling in exposure the same effect as doubling your mAs kV adjustments should not be used to control density
15%
kV determines the _ of the x-ray beam
penetrating ability
as kV is increased the wavelength _ and x-rays become more penetrating
decreases
as kV is decreased, the wavelength _ and x-rays become less penetrating
increases
penetrating ability of the x-rays also determines the numbers of x-rays _the pt. and striking the film
exiting
x-ray photons in the primary beam will spread out from their source and become _ concentrated, as a result x-ray intensity will _ as the distance from the tube is _
less
decreases
increased
the relationship between distance and x-ray quantity is described in the
inverse square law
as distance increases, intensity _, exposure to the IR _
decreases
decreases