rad physics ch.7,8,9 Flashcards

(40 cards)

1
Q

why is the X-ray tube enclosed in a Pb housing?

A

reduce leakage radiation

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2
Q

leakage radiation should not exceed?

A

1 mGya/hr at a distance of one meter

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3
Q

is KE proportional to mass

A

yes

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4
Q

what is the relation of KE and the square of the V

A

Directly proportional

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5
Q

what is the relationship of KE and V

A

not proportional

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6
Q

how do we relate KE in X ray?

A

when electrons go from cathode to anode

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7
Q

how do you find V in the X ray tube?(Formula)

A

v^2=2KE/m

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8
Q

Infrared radiation

A

electrons are raised to a higher energy level and when they return to normal state. outer shell interaction but no ionization

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9
Q

Bremsstrahlung radiation

A

when the projectile electron brakes (curves) around the nucleus

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10
Q

when will more Bremsstrahlung release more radiation

A

when the projectile electron brakes for a longer period of time resulting in a short wavelength with high Bremsstrahlung radiation

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11
Q

at 100 kVp how much bremsstrahlung and characteristic radiation produced

A

85% will be bremsstrahlung and 15% will be characteristic

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12
Q

at what kVp will the target not produce characteristic ionizing radiation

A

69kVp

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13
Q

the greatest number of x-rays have___ of the maximum energy

A

1/3

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14
Q

what is the maximum energy equal to

A

kVp

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15
Q

what part of the X-ray tube is moelydium

A

Neck of the anode

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16
Q

what is amplitude in the X ray tube?

A

quantity of X- ray

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17
Q

an increase in mAs will do what to X-ray Quality, X-ray quantity ?

A

none, increase

18
Q

an increase in kVp will do what to X-ray Quality, x-ray quantity?

A

increase, increase

19
Q

an increase in Distance will do what to X-ray Quality, x-ray quantity?

20
Q

filtration will do what to X-ray Quality, x-ray quantity?

A

increase, reduce

21
Q

what is Half-value layer (HVL)

A

reduces the intensity by half

22
Q

what type of beam does the HVL start with ?

A

heterogenous (high and low energy Beams)

23
Q

after the HVL what type of beam should be left?

24
Q

how much filteraon is in the collimator assembly

25
how much filtration is between the port/housing
1.0-2.0 mm Al/eq
26
what is the required inherent filtration
.5-1 mm Al/eq
27
what is cascading
when the electron hole in the K shell is filled by the L shell
28
does scatter add to patient dose?
yes
29
Compton interaction
incident photon interacts with an outer shell electron and creates an ejection the the electron called the recoil electrons and scattered photon.
30
Compton effect formula
E(incident photon)= E(scattered Photon) +{E(binding energy
31
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
32
names of coherent scattering
classical scattering; Elastic scattering; Unmodifed scattering
33
Quantum Noise
visible as brightness or density fluctuations | Too few X-ray photons= increase quantum noise
34
types of image distortion
size and shape
35
single phase half-wave has how many cycles/sec produced
60 cycles/sec produced
36
single phase full-wave has how many cycles/sec produced
60 cycles/sec produced
37
three-phase, 6 pulsehas how many cycles/sec
60 cycles/ sec produced
38
three-phase, 12 pulse has how many cycles/sec
60 cycles/ sec produced
39
what type if contrast is seen in a photoelectric interaction?
high radiographic contrast; short scale contrast
40
photoelectric interaction formula
PE=1/E^3; PE=Z#^3