Quantity Vs Quality Flashcards
QUANTITY refers to the _____ of the xray beam and is expressed in _____
number
mAs
QUALITY refers to the _____ of the xray beam and is expressed in _____
penetrability
kVp
what is the relationship between quantity and mAs
proportional
what is the expression that describes the relationship between quantity and kVp
(kVp1/kVp2)^2
how is distance related to quantity
by the ISL
xray intensity = ___ =____
xray quantity = xray exposure
units for quantity
Gy or Roentgens
what is the square law
mAs1/mAs2 = SID1^2/SID2^2
when SID increases mAs must be adjusted to maintain exposure to image receptor
what happens with the xray beam upon filtration
beam hardening - increased quality by the filtration of low energy photons
increases average beam energy
what are the 2 types of filtration
inherent filtration
added filtration
in # of photon vs photon energy graph note the differences between an unfiltered beam and filtered beam
un - straight diagonal down
filtered - bell shape
define penetribility
refers to the photons ability to pass through an object
define HVL
thickness of material to reduce beam intensity by a half
define attenuation
reduction in radiation intensity that results from absorption and scatter that occurs as the radiation passes through an object
quantity increases with….
increasing kVp, mAs
decreased distance, filtration
