Ch 10 X-ray Production

higher

x-rays are electromagnetic waves with much _______ energies than light

square

the formula for that total kinetic energy we see that energy changes proportionately to the mass, but it increases by the ______ of the velocity

one-half

electrons crossing the x-ray tube have very small mass, but in just one inch of travel toward the anode they reach speeds more than ______ the speed of light

slow-down

within the atoms of the anode, if the electron passes near the atomic nucleus, the positive attraction of the nucleus will cause it to ____-____

bremsstrahlung
majority

the loss of kinetic energy by this interaction creates x-rays called ________, which account for the vast ______ of the overall x-ray beam

heterogenous
energetic

bremsstrahlung occuring at various distances from the nucleus is responsible for the _______ or poly-________ nature of the x-ray beam

differential
subject

the _______ absorption resulting from a heterogeneous x-ray beam provides ______ contrast to the projected image carried by the remnant x-ray beam and makes the radiographic image possible

create (restore)

a wide range of radiation intensities reaching the imaging detectors makes a full range of information possible. Computers can modify the radiographic image in many ways, but they cannot ________ information that was not present in the first place

higher

the closer the electron passes by the nucleus, the _______ will be the energy of the emitted ray

farther

since the volume of a sphere will increase by the cube of the radius distance, it is statistically much more likely that an electron will pass _______ from the nucleus rather than near it

low
high

hence, many more bremsstrahlung x-rays will be produced at ____ energies than at ____ energies

filtration

most of the very low-energy x-rays produced are absorbed by various materials acting as ________ in the x-ray beam by the time it leaves the collimator

bell
left

the resulting graph of the bremsstrahlung spectrum is a ______-shaped curve which is somewhat lop-sided toward the ______, so that the average kV is roughly one-third of the set peak kilovoltage

area

the total number of x-rays produced is represented by the ____ under this curve

orbital

a characteristic x-ray is produced after a projectile electron ejects an ______ electron from an atom

ground

atoms always seek out the state with the least energy, called their _____ state, in which all electrons reside at the “lowest” possible shell position

orbital (shelf)

a characteristic x-ray is produced when a higher ______ electron is pulled down to fill a vacancy in a lower orbit

potential

when an electron falls from an outer orbit down into an inner orbit, a characteristic x-ray is produced from the loss of ________

Binding

to predict the energy of a characteristic x-ray, simply subtract the ______ energy for the higher shell from that of the vacant shell

57 66 68 69

while very low-energy characteristic x-rays are filtered out of the x-ray beam, for tungsten, those characteristic x-rays having __, __, __, and __ kV largely escape the x-ray tube and are considered part of the useful x-ray beam

excitation

most of the energy (99.5%) emitted from an x-ray tube anode is light and infrared radiation created when outer shell electrons are raised to a slightly higher energy level and then immediately fall back to their normal energy level in a process called ______

atomic number

the higher the _____ ______ of the target material used in the anode, the more efficient it is at “capturing” projectile electrons and more x-rays are produced

energy

target materials with higher atomic numbers also emit x-rays with higher ______

penetration

for mammography, an x-ray beam with lower ______ characteristics is needed, so molybdenum and rhodium are used as target materials

directly

the set milliamperage, the exposure time, and the product of their total mAs, are all ______ proportional to x-ray output from the tube

increases
decreases

added filtration ______ the average energy of the x-ray beam, but slightly ______ the quantity of x-rays

increases
increases

increased kVp _______ the average energy of the x-ray beam, and slightly ______ the quantity of x-rays

bremsstrahlung

higher levels of kVp increase the number of _______ interactions which a high-speed projectile electron can undergo in series within the anode

0.5
1

by increassing the kVp from 60 to 90, the actual efficiency of x-ray production in the anode increases from about ___% to about ___%

40
100

a 15% increase in kVp can add up to ____% to the quantity of x-rays produced, but doubling the mAs, which is equivalent change for the resulting image, doubles the amount of radiation produced, which is a ____% increase

patient

since the final exposure to the image receptor can be doubled by using either a 15%, increase in kVp or by doubling the mAs, there is a savings in ______ exposure when kVp is used rather than mAs to increase average kV

Surge (peak)

for higher-power x-ray generators, the reduced “ripple effect” keeps x-ray production near its “______” stage during an exposure, increasing the average kV

quantity

due to the overlapping of electrical pulses, high-power generators also increase the _____ of x-rays produced during an exposure

right

the result is that the high-power generator beam spectrum is taller, but also shifts its peak to the _____, even though filtration and set kVp are the same