Mid-Term

Question 1

What is an x-ray?

Answer 1

LIGHT; form of electromagnetic ionizing radiation; often called photons; has a wavelength much shorter than that of visible light; produced outside of the nucleus in the electron shells

Question 2

What is another name for single x-ray in the beam?

Answer 2

photon

Question 3

What determines the energy of the x-ray?

Answer 3

the amount of energy of each electron;

short wavelength= high frequency; long wavelength= low frequency

Question 4

Do all of the x-rays in the beam have the same amount of energy?

Answer 4

no; different amounts of energy interacts with different matter

Question 5

What is differential absorption?

Answer 5

difference between those x-rays that pass through tissue and those that don’t

Question 6

What is radiographic density? How does a radiographically dense area appear on a radiograph?

Answer 6

mass per unit volume of black metallic silver; it’s a build up of blackness; it appears black metallic silver

Question 7

How are radiographic density and anatomic density related?

Answer 7

inversely related

Question 8

What is radiographic contrast?

Answer 8

degree of contrast between blacks and whites

Question 9

How do we get contrast in an image? How does that happen?

Answer 9

differential absorption: differences in absorption that transmit the energy of the x-ray and absorption of the tissue

Question 10

Is it really the x-ray that interacts with the film emulsion to produce the image?

Answer 10

No, it is the light from the rare earth screens

Question 11

What would the film look like if all of the x-rays interacted with the emulsion and the film was then processed?

Answer 11

it will get black; when x-rays pass through the tissue, the energy will react with the film and produce blackness

Question 12

What color of light do rare earth crystals typically emit?

Answer 12

green yellowish color

Question 13

Define electromagnetic energy in terms of mass, charge, and velocity

Answer 13

no mass, no charge, travels at the speed of light

Question 14

Define ionize

Answer 14

ability to totally remove an electron from it’s orbit around the nucleus

Question 15

Which types of electromagnetic energies are able to ionize?

Answer 15

x-rays, gamma rays, some short UV rays

Question 16

State the wave equation

Answer 16

velocity= frequency x wavelength

v) (f) (lambda

Question 17

What is a gamma ray?

Answer 17

form of ionizing electromagnetic radiation; emitted from nucleus of a radioisotope and are usually associated with alpha or beta emission

Question 18

What is the difference between x-rays and gamma rays?

Answer 18

origin; x-rays are located in the electron shells while gamma rays are from the nucleus

Question 19

Why is a free electron a worry in human tissue?

Answer 19

Because they are highly reactive and believed to be involved in degenerative diseases and cancers.

Question 20

3. List other types of electromagnetic energies in order of their energies relative to x-ray

Answer 20

Tv, radio, microwaves, infrared light, ultraviolet light, x-rays, gamma rays

Question 21

range of x-rays in matter

Answer 21

1 – 100 meters in air

0-30 cm in soft tissue

Question 22

What makes an x-ray photon higher energy than a microwave

Answer 22

the difference in wave frequency

Question 23

1. HOW MUCH OF THE ELECTRIC AND KINETIC ENERGY OF THE PROJECTILE ELECTRONS IS CONVERTED TO HEAT? X-ray?

Answer 23

99%

<1%

Question 24

Is heat production an excitation interaction or an ionization interaction?

Answer 24

excitation interaction

Question 25

What 2 methods are x-rays produced by?

Answer 25

characteristic and Bremsstrahlung

Question 26

5. WHICH OF THESE METHODS PRODUCES X-RAYS WHEN ELECTRONS SHIFT ENERGY LEVELS / SHELLS WITHIN THE ATOM?

Answer 26

characteristic

Question 27

Tungsten is used as a target material. It has electron shells from "__" (near the nucleus) to "__" (outermost shell).

Answer 27

K", "P"

Question 28

Which characteristic x-rays of tungsten are energetic enough to be useful?

Answer 28

K orbital

Question 29

AT LEAST ______ kVp IS REQUIRED TO PRODUCE USEFUL ENERGY K-CHARACTERISTIC X-RAYS OF TUNGSTEN.

Answer 29

69.53 kVp

Question 30

X-rays are converted from ___ energy to ___ energy.

Answer 30

kinetic, electromagnetic

Question 31

Does an alpha particle or x-ray cause a double strand break in DNA?

Answer 31

alpha particle

Question 32

What are the kVp values needed for each characteristic orbital?

Answer 32

``` K=69.53 L=12.1 M=2.82 N=.6 O=.08 P=not bound ```

Question 33

The vast majority of x-rays are produced by which production process?

Answer 33

Bremsstrahlung

Question 34

9. THE CHARACTERISTIC X-RAY WITH THE MOST KeV OF ENERGY OCCURS WITH THIS ELECTRON TRANSITION : _____TO _____.

Answer 34

P to K

Question 35

In Bremsstrahlung production process, what is the range of energy?

Answer 35

0-125 kVp

Question 36

What is the highest energy x-ray in a beam dependent on?

Answer 36

kVp

Question 37

Describe the Bremsstrahlung x-ray production process.

Answer 37

main way xrays are produced. b/c nucleus is + and electron is -, the electron travels close to nucleus and gets drawn to it and deflected from its original direction. this deflection causes a loss of energy and that loss is formed into an xray photon

Question 38

Describe the characteristic x-ray production process.

Answer 38

interaction of the projectile electron with the k-shell target electron. the electon is kicked out of its shell. an electron from an outer shell then fills in where the electron left. the energy level drops causing a photon to be emitted.

Question 39

WHAT IS THE AVERAGE ENERGY OF AN X-RAY BEAM PRODUCED AT 80 KVP?

Answer 39

1/3)*80 = 26.67 kVp

Question 40

What is the purpose of the rectifier?

Answer 40

to let the electrical current flow in one direction, from cathode to anode, AC to DC, - to +

Question 41

whatt type of current is required to produce x-rays?

Answer 41

DC

Question 42

What does the power company provide for us?

Answer 42

AC, alternative current

Question 43

What does kVp do inside the tube to produce x-rays?

Answer 43

it determines the quality of the x-ray beam

Question 44

Which type of rectification produces the highest contrast radiograph?

Answer 44

Full Wave Rectification

Question 45

Which type of rectification produces the highest energy x-rays, uses a 110 outlet, and reduces the patients exposure over 30%?

Answer 45

Hight Frequency rectification

Question 46

What is MAS?

Answer 46

of x-rays being produced

Question 47

What is kVp?

Answer 47

energy of x-rays

Question 48

What is isotropic emission?

Answer 48

360degrees divergence of light

Question 49

What is thermionic emission?

Answer 49

boiling off electrons

Question 50

What is a cathode?

Answer 50

- negatively charged electrode - contains small and large filament - source of electrons for the production of x-rays - where electrons "boil" off

Question 51

What is a anode?

Answer 51

- positively charged electrode - spinning disc - acts as a coolant by distributing heat

Question 52

What is the main function of the filter?

Answer 52

to reduce skin dose of radiation to the patient

Question 53

What is the x-ray tube made of?

Answer 53

blown glass or metal ceramic

Question 54

What is the advantage of the small filament?

Answer 54

produces a sharper image

Question 55

What is the advantage of the large filament?

Answer 55

shorter exposure time

Question 56

How is the filament/focal spot selected?

Answer 56

by selecting the mA

Question 57

What photographic property does mAs control?

Answer 57

density

Question 58

What electrical unit is set on the console to accelerate the electrons from cathode to anode?

Answer 58

kVp

Question 59

What photographic quality does the kVp control?

Answer 59

contrast

Question 60

What is contrast?

Answer 60

a photographic property that shows the degrees of difference between black, white and various shades of gray

Question 61

The anode spins at ___rpm.

Answer 61

3,600rpm

Question 62

How long should the anode spin after exposure is terminated to be sure there is no rotor bearing damage?

Answer 62

at least 90 seconds

Question 63

What type of motor spins the anode?

Answer 63

electrical induction

Question 64

What is the target area of the anode made of?

Answer 64

tungston

Question 65

The focusing cup has a strong _____ charge to keep the electrons focused into a small focal spot area on the target of the anode.

Answer 65

positive

Question 66

What is the tube housing lined with?

Answer 66

lead

Question 67

What is the tube housing filled with?

Answer 67

oil to dissipate heat

Question 68

What is the opening called that allows x-rays out of the housing tube?

Answer 68

port

Question 69

Define ALARA

Answer 69

As low as reasonably achievable

Question 70

Which rectification is most consistent with ALARA

Answer 70

Full Wave Rectification

Question 71

Which of these types of rectifiers will extend the tube life?

Answer 71

High Frequency Rectification

Question 72

Compare the cost of Full Wave Rectification to High Frequency Rectification.

Answer 72

HF is $3000 more

Question 73

How much of a change in mAs if underexposed?

Answer 73

increase 100%

Question 74

How much of a change in mAs if over exposed?

Answer 74

decrease 1/2

Question 75

increase in kVp would be an ___ of KE, to an ____ of x-ray energy (______wave length)

Answer 75

increase, increase, shorter

Question 76

the anode side of the tube can be located by:

Answer 76

negative label, positive label, listening for the spin, finding the wire for the AC current

Question 77

Which side of a radiograph will exhibit the least radiographic density?

Answer 77

The anode

Question 78

The high atomic # of the tungsten target absorbs low energy x-rays.

Answer 78

False

Question 79

Where should the anode side of the tube be placed when performing a lateral thoracic spine radiograph?

Answer 79

down

Question 80

Where should the anode side of the tube be placed when performing a lateral lumbar spine radiograph?

Answer 80

up

Question 81

Where should the anode side of the tube be placed when performing an AP thoracic spine radiograph?

Answer 81

up

Question 82

Where should the anode side of the tube be placed when performing a full spine radiograph on a 14 x 36" film?

Answer 82

up

Question 83

Where should the anode side of the tube be placed when performing a lateral cervical spine radiograph?

Answer 83

It doesn't matter on a 10x12" film at 40"

Question 84

When the anode heel effect becomes important in terms of film size and source image distance (SID).

Answer 84

Large film sizes at short SID

Question 85

How does placing the anode / cathode side in the proper place affect the radiograph's overall density.

Answer 85

It produces uniform in density

Question 86

Besides using the anode heel effect properly there are two other options that may help to produce a more uniform film density. They include:

Answer 86

Compensating Filters | Slow Speed where area is thin; faster speed where is thickest.

Question 87

How should you have your tube installed? (Which side up?)

Answer 87

anode

Question 88

Which side of the radiograph will be the sharpest?

Answer 88

anode

Question 89

The ____ side of the x-ray tube emits x-rays that are relatively perpendicular to the film.

Answer 89

anode

Question 90

State the unit that a physicist would use to describe ionizations in air in classical nomenclature.

Answer 90

R

Question 91

State the unit that a physicist would use to describe ionizations in air in Systems International nomenclature.

Answer 91

Coulombs/kg

Question 92

Coulombs/kg measure this type of radiation only:

Answer 92

X-ray and gamma

Question 93

State the unit for occupational exposure in classical nomenclature.

Answer 93

REM

Question 94

State the unit for occupational exposure in Systems International nomenclature.

Answer 94

Sievert

Question 95

___ mRem = 1 Rem

Answer 95

1,000

Question 96

State the formula for Rem. Rem = _____ x _____.

Answer 96

RAD x QF (quality factor)

Question 97

20 mRad of x-ray exposure = ____ mRem

Answer 97

20

Question 98

100 Rem = ______Sievert.

Answer 98

1

Question 99

State the unit of absorbed dose in classical nomenclature.

Answer 99

RAD

Question 100

State the unit of absorbed dose in Systems International nomenclature.

Answer 100

Gray

Question 101

100 Rad = _____Gray

Answer 101

1

Question 102

In x-ray: ____R = _____Rad = _____Rem

Answer 102

1,1,1

Question 103

Comparing annual radiation exposure to the population in the U.S., most exposure comes from this source:

Answer 103

background: cosmic, terrestrial

Question 104

List at least 3 consumer products that contribute to background exposure.

Answer 104

Tobacco, Television, Combustible Fuels

Question 105

State the annual whole body MPD for occupationally exposed persons in Rem.

Answer 105

5 REM

Question 106

State the average annual exposure that medical personnel receive.

Answer 106

< 100 mREM