1. XR Production

Question 1

Describe nomenclature for elements

Answer 1

X: chemical symbol for atom
A: mass number (protons + neutrons)
Z: atomic number (protons)

Question 2

How does atomic number influence binding energy?

Answer 2

increase Z, binding energy

Question 3

what is binding energy?

Answer 3

energy required to free an electron from a shell

Question 4

How does distance between nucleus and electron impact binding energy?

Answer 4

decreases binding energy

Question 5

Describe elecromagnetic radiation?

Answer 5

wave of energy that can travel in vacuum, travels at 3 x 10 to the 8 m/s

Question 6

Describe relationship of frequency and wavelength

Answer 6

inverse

Question 7

Frequency

Answer 7

cycles/second

Question 8

wavelength

Answer 8

distance between peaks

Question 9

energy required to become ionizing radiation

Answer 9

15 ev

Question 10

small wavelength = ? energy

Answer 10

high

Question 11

gamma rays

Answer 11

emitted by nucleus; given during atom decay

Question 12

x-ray

Answer 12

interactions between electrons/atoms

Question 13

alpha particle and net charge

Answer 13

2 protons, 2 neutrons; net charge 2+, very attractive to electrons

Question 14

beta particle

Answer 14

electron ejected from nucleus

Question 15

isotopes

Answer 15

element with different number of neutrons and mass number A; same Z

Question 16

maximum number of electrons that a shell can hold

Answer 16

2n to the second power

Question 17

which shell has the higher binding force?

Answer 17

innermost shell, K > L > M

Question 18

what is the kinetic energy of bound particles?

Answer 18

negative, most negative potential in the innermost shell

Question 19

at what kinetic energy can the electron break free or reach binding energy?

Answer 19

0

Question 20

synonym for binding energy

Answer 20

ionization potential; energy needed to remove electron from atom

Question 21

what can increase/decrease binding energy?

Answer 21

increase: more protons
decrease: farther distance from nucleus

Question 22

characteristic energy of an emitted x-ray/photo depends on?

Answer 22

atom involved and electron shell involved

Question 23

Why is tungsten filament used ?

Answer 23

1) high melting temperature (>2000 degrees) so electrons can be “boiled off” thermionic emission;
2) high atomic number makes it a good the thermionic emitter

Question 24

tungsten filament is anode or cathode?

Answer 24

cathode, negative end; slight positive charge so electrons go to anode

Question 25

3 ways electrons lose kinetic energy

Answer 25

excitation, ionization, radiative losses (Bremsstrahlung)

Question 26

electron cloud around the filament

Answer 26

space charge

Question 27

Space Charge effect

Answer 27

space charge limits the emission of electrons

Question 28

milliampere, mA

Answer 28

unit used to describe current; quantity of electrons moving from cathode to anode; electrons/sec moving from filament to target

Question 29

effect of doubling mA

Answer 29

doubles the xrays

Question 30

KvP affects quality or quantity?

Answer 30

both

Question 31

mA affects quantity or quality?

Answer 31

quantity

Question 32

goal of focusing cup?

Answer 32

keep electrons together as their negative charge will keep make them spread/separate

Question 33

Why does the anode rotate?

Answer 33

to disperse heat over larger surface area as the xrays hit it; prevent anode from melting; it is usually connected to a molybdenum stem

Question 34

what is the focal spot?

Answer 34

target zone for electrons from the cathode filament

Question 35

apparent/effective focal spot vs actual focal spot

Answer 35

actual: where electrons land apparenet: where x-rays land on patient (affects blur)

Question 36

smaller anode has better/worse spatial resolution?

Answer 36

better

Question 37

downside of small anode

Answer 37

can't disperse heat, more prone to melt; can get around by angling anode or rotating anode

Question 38

mammo focal spot

Answer 38

0.3-0.1 mm

Question 39

xray focal spot

Answer 39

0.6-1.2 mm

Question 40

portable x-ray device uses rotating vs stationary anode?

Answer 40

stationary

Question 41

small focal spot results in ?

Answer 41

best resolution; lower heat tolerance

Question 42

Line Focus Principal

Answer 42

angling target (anode) will keep actual focal spot large but effective focal spot small

Question 43

small angle = ___ effective focal spot = ___ heel effect

Answer 43

small, greater (heel cut off)

Question 44

Heel effect

Answer 44

loss of xray energy due to angling of target

Question 45

smaller angle = ___ heel effect

Answer 45

worsening, loss of energy

Question 46

highest intensity in heel effect is on the ____ side

Answer 46

cathode side (used in mammo); cathode is against the chest wall vertical orientation with a CXR with cathode at lung bases/lower thoracic spine

Question 47

larger focus to film distance, the _____ the heel effect

Answer 47

less

Question 48

smaller film = ____ heel effect

Answer 48

less; central beam is most uniform

Question 49

how does increasing Z impact Bremsstrahlung curve?

Answer 49

increase atomic number increases overall xrays produced; increases quantity; no change in characteristic peaks or quality

Question 50

How does kVP influence quantity/quality?

Answer 50

increase, quantiy increases as a square of kvp

Question 51

kvp define

Answer 51

maximum or peak energy of electron stream

Question 52

what is the relationship between mA and quantity?

Answer 52

direct; increasing mA increase electrons

Question 53

15% rule?

Answer 53

increasing kVP by 15%, decrease mA by 1/2 to maintain same xray intesnsity decrease kVP 15%, double mA

Question 54

single vs three phase generator for kVP?

Answer 54

triple phase is better at keeping kVP constant, but peak of curve is still not changed; triple phase has less ripple (more quantity/quality)

Question 55

half value layer

Answer 55

amount of material attenuates x ay to half original output; depends on photon energy ; each consecutive HVL is greater than the last since the weaker photons are shifted out

Question 56

HVL on quality and quantity

Answer 56

``` increases quality (filters out weaker photons) decreases quantity (filters out weaker photons) ```

Question 57

what is the 10th HVL?

Answer 57

thickenes of material that can attenuate 90% of xrays, used for shielding calculations