rad physics ch.7,8,9 Flashcards
why is the X-ray tube enclosed in a Pb housing?
reduce leakage radiation
leakage radiation should not exceed?
1 mGya/hr at a distance of one meter
is KE proportional to mass
yes
what is the relation of KE and the square of the V
Directly proportional
what is the relationship of KE and V
not proportional
how do we relate KE in X ray?
when electrons go from cathode to anode
how do you find V in the X ray tube?(Formula)
v^2=2KE/m
Infrared radiation
electrons are raised to a higher energy level and when they return to normal state. outer shell interaction but no ionization
Bremsstrahlung radiation
when the projectile electron brakes (curves) around the nucleus
when will more Bremsstrahlung release more radiation
when the projectile electron brakes for a longer period of time resulting in a short wavelength with high Bremsstrahlung radiation
at 100 kVp how much bremsstrahlung and characteristic radiation produced
85% will be bremsstrahlung and 15% will be characteristic
at what kVp will the target not produce characteristic ionizing radiation
69kVp
the greatest number of x-rays have___ of the maximum energy
1/3
what is the maximum energy equal to
kVp
what part of the X-ray tube is moelydium
Neck of the anode
what is amplitude in the X ray tube?
quantity of X- ray
an increase in mAs will do what to X-ray Quality, X-ray quantity ?
none, increase
an increase in kVp will do what to X-ray Quality, x-ray quantity?
increase, increase
an increase in Distance will do what to X-ray Quality, x-ray quantity?
none, reduce
filtration will do what to X-ray Quality, x-ray quantity?
increase, reduce
what is Half-value layer (HVL)
reduces the intensity by half
what type of beam does the HVL start with ?
heterogenous (high and low energy Beams)
after the HVL what type of beam should be left?
Homogenous
how much filteraon is in the collimator assembly
1.0 mm Al/eq
how much filtration is between the port/housing
1.0-2.0 mm Al/eq
what is the required inherent filtration
.5-1 mm Al/eq
what is cascading
when the electron hole in the K shell is filled by the L shell
does scatter add to patient dose?
yes
Compton interaction
incident photon interacts with an outer shell electron and creates an ejection the the electron called the recoil electrons and scattered photon.
Compton effect formula
E(incident photon)= E(scattered Photon) +{E(binding energy
Photoelectric interaction
electron interacts with an inner shell electron which leads to the incident being absorbed. By-products are photoelectron- ejectedhlectron and characteristic radiation aka florescent radiation
names of coherent scattering
classical scattering; Elastic scattering; Unmodifed scattering
Quantum Noise
visible as brightness or density fluctuations
Too few X-ray photons= increase quantum noise
types of image distortion
size and shape
single phase half-wave has how many cycles/sec produced
60 cycles/sec produced
single phase full-wave has how many cycles/sec produced
60 cycles/sec produced
three-phase, 6 pulsehas how many cycles/sec
60 cycles/ sec produced
three-phase, 12 pulse has how many cycles/sec
60 cycles/ sec produced
what type if contrast is seen in a photoelectric interaction?
high radiographic contrast; short scale contrast
photoelectric interaction formula
PE=1/E^3; PE=Z#^3
