Radiation Physics

Question 1

what is kinetic energy transmitted by tiny massed moving particles at high velocities

Answer 1

particulate radiation

Question 2

what is pure energy with no mass traveling as waves at the speed of light

Answer 2

electromagnetic radiation

Question 3

what are alpha beta and cathode rays

Answer 3

particulate radiation

Question 4

what are small energy packets known as photons

Answer 4

electromagnetic radiation

Question 5

lambda represents…

Answer 5

wave length

Question 6

what is the distance between two EMR wave crests called

Answer 6

wave length

Question 7

smaller lambda means…

Answer 7

shorter wavelength with high frequency

Question 8

larger lambda means…

Answer 8

longer wavelength and lower frequency (less peaks)

Question 9

x rays are a form of…

Answer 9

electromagnetic radiation

Question 10

true or false: xrays have higher energy than visible light and can pass through most objects

Answer 10

true

Question 11

what are waves that interact and cause removal of electrons from the orbits of atoms creating ion pairs

Answer 11

ionizing radiation

Question 12

what are types of radiation that do not cause removal of charged particles

Answer 12

non ionizing

Question 13

protons are

Answer 13

positive

Question 14

neutrons are

Answer 14

neutral

Question 15

electrons are

Answer 15

negative

Question 16

a stable atom has

Answer 16

a neutral nucleus

Question 17

an atom with a charge

Answer 17

ion

Question 18

the process of converting an atom into an ion by adding or removing electrons

Answer 18

ionization

Question 19

xray beams are made up of

Answer 19

photons

Question 20

photons are

Answer 20

bundles of electromagnetic energy with no mass and no charge

Question 21

travel through space at speed of light in straight lines

Answer 21

xrays

Question 22

interact with orbital electrons within the patient and receptor

Answer 22

xrays

Question 23

metal body around the tube

Answer 23

metal housing

Question 24

oil surrounding the tube and transformers absorbs heat

Answer 24

insulating oil

Question 25

- end of tube head

Answer 25

cathode

Question 26

+ end of tube head

Answer 26

anode

Question 27

tungsten embedded in copper head

Answer 27

target

Question 28

coil that heats to generate electrons

Answer 28

filament

Question 29

molybdenum cup that focuses the electrons to the small focal spot on the target

Answer 29

focusing cup

Question 30

create a large voltage potential to help electrons travel and photons form

Answer 30

transformers

Question 31

kVp

Answer 31

kilovolt potential

Question 32

helps filter out low frequency non-useful waves

Answer 32

aluminum filter

Question 33

seal around tube

Answer 33

leaded glass seal

Question 34

reduces size of the beam

Answer 34

collimator

Question 35

device that either increases or decreases voltage in an electrical circuit

Answer 35

transformers

Question 36

step down transformer is a .... voltage circuit

Answer 36

low

Question 37

step down transformer does what

Answer 37

creates a lower voltage at the filament (3-5 volts) to heat the filament and create the electron cloud

Question 38

how much does the step down transformer decrease the voltage

Answer 38

110-220 down to 3-5V

Question 39

step up transformer does what

Answer 39

increases voltage across the circuit to give more energy to the electrons and send electron cloud across to the target

Question 40

how much does a step up transformer increase the voltage

Answer 40

110-220 to 65k-100k V

Question 41

helps make adjustments to correct for fluctuations

Answer 41

autotransformer

Question 42

step 1 of creating an xray

Answer 42

heating of the filament

Question 43

step 2

Answer 43

thermionic emission of electron

Question 44

step 3

Answer 44

acceleration of the electron across from cathosde to anode

Question 45

step 4

Answer 45

electron strikes the target anode

Question 46

step 5

Answer 46

lots of heat and photons created due to transfer of kinetic energy

Question 47

how many ways to create a photon

Answer 47

two

Question 48

70% of radiation is made by

Answer 48

general radiation aka braking radiation

Question 49

when the electron knocks out an inner electron and neighboring electrons try to fill the vacancy, resulting rearrangement causes loss of energy which produces a photon

Answer 49

characteristic radiation

Question 50

only happens at 70 keV or above and energy amount will differ depending on target material

Answer 50

characteristic radiation

Question 51

how is the photon beam filtered

Answer 51

first by leaded glass tube then by added aluminum filtration

Question 52

filtering photon beam is important because

Answer 52

it reduces radiation to the patient by filtering out long wavelength low frequency waves

Question 53

amount of aluminum thickness it takes to reduce radiation by 50%

Answer 53

half value layer (HVL)

Question 54

properties of xrays

Answer 54

- invisible - no mass or weight - no charge - speed of light - waves and straight lines - cannot be focused on one point - penetrate all forms of matter - absorbed by matter - causes certain things to flouresce - produces image on receptor - can cause biologic changes in living cells

Question 55

process of producing dental xrays (3 steps)

Answer 55

1 - filament circuit is activated, heats up, and thermionic emission occurs 2 - exposure button is activated, electrons are accelerated from cathode to anode 3 - electrons strike the tungsten target and their kinetic energy is converted to xrays and heat

Question 56

when an electron dislodges a K orbital electron of the tungsten target

Answer 56

characteristic radiation

Question 57

happens when an electron is slowed down as it approaches the nucleus of the tungsten atom

Answer 57

brehmstrahlung radiation (general) (braking)

Question 58

how x radiation can interact with a patient

Answer 58

- can pass thru patient - can be absorbed by patient - photons can be scattered

Question 59

new x ray is scattered in different direction than original

Answer 59

coherent scatter (7-8%)

Question 60

x ray is absorbed and vanishes

Answer 60

photoelectric effect (27-30%)

Question 61

new weaker xray is formed and scattered in new direction

Answer 61

compton effect (57-62%)

Question 62

results in loss of an electron and ionization of absorbing atom

Answer 62

compton scatter

Question 63

varies directly with electron density of absorber (bone more than soft issue)

Answer 63

compton scatter

Question 64

what percentage of scattered photons leave the patients head in compton scatter

Answer 64

30%

Question 65

pros and cons of compton scatter

Answer 65

- reduces exposure (pro) - may hit recpetor and produce fog (bad) - exposure for operator (bad)

Question 66

primary beam or useful beam that exits the tubehead

Answer 66

primary radiation

Question 67

x rad that is created when the primary beam interacts with matter (patient's tissues etc.) which is less penetrating

Answer 67

secondary radiation

Question 68

type of secondary radiation when an xray interacts with matter and is deflected

Answer 68

scatter