CLUSTER II

Question 1

Where conversion of electrical energy and em energy occurs

Answer 1

X-ray tube

Question 2

An x-ray tube is a [..] tube all gasses have been removed to allow flow of electron

Answer 2

Vacuum tube

Question 3

An x-ray tube is a diode tube — consists of 2 electrodes [..] and [..]

Answer 3

Cathode and anode

Question 4

Negative side of the tube

Answer 4

Cathode

Question 5

Parts of cathode

Answer 5

Focusing cup
Filament

Question 6

Focusing cup is made up of [..]

Answer 6

Nickel

Question 7

Filament is made up of [..] and [..]

Answer 7

Thorium and tungsten

Question 8

Positive side of the tube

Answer 8

Anode

Question 9

Parts of the anode side

Answer 9

Target
Rotor
Stator

Question 10

3 elements of x-ray production

Answer 10

1. Electrons - produced in filament
2. Voltage- determines energy of e
3. Target atom - composition of anode target; determines kvp

Question 11

Radiation Production in X-ray Tube [L.F.A.D]

Answer 11

1. Rotor Switch - no x-rays produced yet
   A. Liberation
   B. Focusing
2. Exposure Switch - production of x-rays
   A. Acceleration
   D. Decceleration

Question 12

Explain ROTOR SWITCH in x-ray production

Answer 12

ROTOR SWTCH
Liberation -
1. mA is supplied to (-) filament -> thermionic emission (liberation/emission) of e from filament due to heat
2. mA is supplied to (+) stator -> EM induction (electric current creates magnetic field -charge and motion -) -OERSTED

Focusing-
Focusing cup (-) to repel e; e move fwd in limited pathway of e beam

Question 13

explain EXPOSURE SWITCH in x-ray production

Answer 13

EXPOSURE SWITCH
Acceleration -
1. Movement of kV from (-) side to (+) side
Deceleration - abc
2. Movement of e is stopped, e is converted to EM energy
-conversion of electrons- anode heat, characteristic x-ray and bremsstrahlung x-ray

Question 14

explain Deceleration [ABC]

Answer 14

Anode Heat - outer shell target e- interaction; excitation 99%
Bremsstrahlung - eleven energies; polyenrgetic energy. Nuclear Field: LLL
Characteristic - inner shell target e- interaction; ionization

Question 15

x-ray quality is controlled by [..]

Answer 15

Energy (kVp)

Question 16

x-ray quantity is controlled by [..]

Answer 16

no/amount of x-rays

Question 17

x-ray interaction wherein x-rays passes through matter and reaches IR

Answer 17

Transmission

Question 18

direct Relationships with kVp

Answer 18

DFREQNCIS
Density
Frequency
Rad’n quality
Energy
Quantity
Number of x-rays
Compton Scatter
Intensity
Scatter Radiation

Question 19

inverse relationships with kVp

Answer 19

We Can Pass
Wavelength
Contrast
Patient Dose

Question 20

direct relationships with mAs

Answer 20

PX RDN
Patient Dose
X-ray quantity
Radiation intensity
Density
Number of x-rays

Question 21

inverse Relationships to SID

Answer 21

PaReDe
Patient Dse
Radiation Intensity
Density

Question 22

range of exposure factors that will provide the range of acceptable densities/ optimum density level

Answer 22

Exposure latitude

Question 23

[exposure technique charts] fixed mAs (highest mAs) high
ED JERMAN 1925
KVP= (pt thickness x 2) + k

Answer 23

Variable kVp

Question 24

[exposure technique charts] variable mAs; (highest kVp) low contrast-low exposure, low pt dose, wide expo lat
ARTHUR FUCHS 1942

Answer 24

Fixed kVp

Question 25

[exposure technique charts] >100 kvp, not for thin poi, rec for adult cxr and barium studies

Answer 25

high kvp technique

Question 26

optimum optical density level [..]-[..]

Answer 26

0.25-2.5 OD

Question 27

[type of automatic exposure control] used in old DR, located below IR, more pt rad dose, measures light intensity

Answer 27

Phototimer

Question 28

[type of automatic exposure control] used in new DR, located above IR, less pt radiation, uses XENON - measure how much ionization happens in the air

Answer 28

Ionization Chamber

Question 29

process of removing low energy x-rays (beam hardening)

Answer 29

filtration

Question 30

Filtration reduces pt dose by [..] per 2.5mm Al equivalent

Answer 30

Filtration reduces pt dose by 50% per 2.5mm Al equivalent

Question 31

[filtration] inherent filter

Answer 31

inside-xr tube 0.5mm Al eq; tube window, diala oil

Question 32

[filtration] added filter

Answer 32

outside xr tube after exit port 1.0 mm Al eq; 45 deg mirror - 1.0 mm Al eq

Question 33

[filtration] total filtration

Answer 33

sim of inherent 0.5 + added 2.0 mm Al = 2.5 mm Al eq = 1 HVl

Question 34

approp filtration need for: >70 kVp = [..] 50-70 kVp = [..] <50 kVp = [..]

Answer 34

>70 kVp = 2.5 mm Al 50-70 kVp = 1.5 mm Al <50 kVp = 0.5 mm Al

Question 35

[filtration] compensates for tissue thickness difference, provide uniform lvl of density across the image

Answer 35

compensating filter

Question 36

factors affecting technical factors of choice

Answer 36

↑ATM Atomic Number Patient Thickness Mass Density

Question 37

Mass Density of Body parts [ lowest to highest)

Answer 37

AiLoveFoodSoBad Air Lung Fats Soft Tissue Bone

Question 38

radiopaque pathologies ↑ in ATM

Answer 38

Constructive/ Additive

Question 39

radiolucent pathologies ↓ in ATM

Answer 39

Destructive/Destructive

Question 40

other names for Compton Scattering

Answer 40

modified, incoherent, non-classical, inelastic

Question 41

Photoelectric vs. Compton

Answer 41

PE no diag value characteristic xr ↑ contrast ↑ pt dose Compton ↑ diag value ↑Scatter ↑personnel dose ↓contrast

Question 42

[direction and probability of scatter]

Answer 42

grazing hit 90 degree hit backscatter

Question 43

[direction and probability of scatter] grazing hit

Answer 43

direction is forward; 80%

Question 44

[direction and probability of scatter] 90 degree hit

Answer 44

formation is at right angle; 75%

Question 45

[direction and probability of scatter] backscatter

Answer 45

aka direct hit; towards tube/source; 60%