Technical Factors Flashcards
energy conversion when fast-moving electrons interacts with the anode
xrays
incident electrons interacts with the force field of the nucleus
bremsstrahlung interaction
german word for breaking or slowing down
bremsstrahlung
incident electron interacts with an inner-shell electron
characteristic interaction
only _______ has sufficient energy photon to produced useful beam
K-shell characteristics
their energy difference between the binding energies of the shell involved in the interaction
characteristic photons
tungsten target have energies of
59-69 kEv
molybdenum target have energies of
17-20 kEv
refers to the intensity of Xray measured by mR
Radiation Quantity
refers to the energy of the xray beam
Radiation Quality
4 technical factors in radiography
mA
Sec
kVp
Distance
it controls the current supplied to the filament
mA
controls the length of time the tube
controls the intensity of xray beam
sec
any combination of mA and time which yield the same product will result to the same density
Reciprocity law
states that at very short and very long exposure time, the resultant density is somewhat less than what is expected
Reciprocity law failure
intensity of xray photons
mAs
the intensity of the xray beam decreases by a factor of four with the square of the distance
Inverse square law
Affects the intensity of the xray beam that will interacts with the xray film
distance
affects the penetrability of the xray beam and image contrast
kVp
kVp =
thickness (cm) x 2 / constant
used to measure thickness of the body in cm
caliper
increasing kVp by 15% will result to the same increase in density as doubling the mAs
15% kVp rule
