week 6 - 8 review (exam)

Question 1

Xray tube charges

Answer 1

Anode - target side of x-ray tube (+)
cathode - filament side of X-ray tube (-)

Question 2

electricity

Answer 2

energy used to make x-rays

Question 3

Electrical current

Answer 3

flow of electrons through a conductor

Question 4

Amperage and miliaperes (general)

Answer 4

Measurement of the number of electrons moving through a conductor
mili - increase of decrease # of electrons passing through cathode

Question 5

Voltage and kilovolts (general)

Answer 5

measurements of electrical force that causes electrons to move from negative pole to a positive pole
Kili - control the current passing from cathode to anode

Question 6

Types of transformers (3 types)

Answer 6

1. Step-down transformer (ON button) - 3-5 voltage to heat up tungsten and forms electron could
2. step-up transformer (connected to exposure button) - 55 k - 100k high voltage and difference between low and high volts free the electrons from the filament
3. autotransformers - corrects for minor fluctuations in current

Question 7

Filtration

Answer 7

1. Aluminum filtration - removes long wavelength photons
2. total filtration (glass tube, insulating oil, barrier)
3. lead collimator - allows the shape and size of beam to be controlled (rectangular 50% less than circular)

Question 8

Absorption radiation (explained)

Answer 8

radiation energy is absorbed by photons colliding with electrons of the atoms of an absorbing material
- higher the atomic weight, better energy absorption (lead)

Question 9

3 ways x-ray photons can be absorbed

Answer 9

1. pass through patient and expose film
2. absorbed by patient - never reaches film
3. x-ray photon may be scattered onto the fly or ways from film (film fogging)

Question 10

photoelectric absorption

Answer 10

total absorption of X-ray photon energy (ejected electron is called photoelectron)

Question 11

Compton absorption

Answer 11

Partial absorption of x-ray photon energy (scattered, longer wave length, ejected orbital electron (Compton electron)

Question 12

Thompson/coherent scattering

Answer 12

photon of scattered radiation, no loss of energy just different direction

Question 13

Quality vs quantity

Answer 13

quality - penetrating ability
quantity - amount

Question 14

Controls that directly influences with quant and qual

Answer 14

exposure time, mA, kVp, PID

Question 15

things that will indirectly influence the settings choose on X-ray unit

Answer 15

film speed/imaging sensor plate, film processing, patient size

Question 16

Amperage (in detail)

Answer 16

Unit of quality of electric current, increase amps results in increase in # of electrons produced in cathode

Question 17

Miliapere (in detail) mA

Answer 17

1/1000 ampere, only small current used in dental, total # of x-rays produced depends on mA exposure time
(directly influences # of electrons striking target - # produced)

Question 18

Voltage (in detail)

Answer 18

electrical pressure, amount will determine the speed of electrons which gives energy (penetrating power)

Question 19

kilovolt

Answer 19

1 kVp = 1000 volts

Question 20

mA rule of thumb (thermionic emission)

Answer 20

directly influences # of electrons striking target, hence # of photons produced
increased mA: 10 to 25 = 30% more radiation
Decrease mA: 15 to 10 = 30% less radiation

Question 21

Time influence

Answer 21

(length of time unit produced X-rays - direct prop)
longer time = more x-rays, less time = fewer x-rays
Double time = 2x rad
half time = 50% less rad

Question 22

kVp

Answer 22

only component that will influence penetrating ability of the beam of radiation Directly influences the speed electrons impact target, thus the efficiency of the x-ray proton
- 15 kVp increase - increase intensity by 2x
- 15 kVp decrease - decrease intensity by 50%

Question 23

Inverse square law (PID)

Answer 23

the intensity of the radiation is inversely proportional to the square of the distance
- 8 in to 16 in reduced intensity to 1/4 value at 8
- 16 in to 8 in increased intensity to 4x value at 16 in

Question 24

Electron binding energy

Answer 24

• Electrons in orbital (negative charge) are attracted to protons (positive charge) in nucleolus
  
  • Further away from nucleolus, less binding energy, easier to remove from orbital
  • Near nucleolus, greater binding energy, harder to remove form orbital

Question 25

Radiation atom

Answer 25

large, lots of electrons, easy to steal from outer shell ○ Tungsten, lots of electrons - requires less energy to remove them

Question 26

Ionization

Answer 26

- Radiation can change an atom (removal of electrons) - Electrically neutral - same number of electrons as we do protons If electrons are pulled away ends up an ion

Question 27

Radiation

Answer 27

the emission and propagation of energy through a space of substance in the form of waves or particles

Question 28

Radioactivity

Answer 28

the process by which certain unstable atoms or elements undergo spontaneous disintegration, or decay, in effort to attain a more balanced nuclear state (energy is given off as the nuclei disintegrates)

Question 29

what is particulate radiation

Answer 29

posses mass and travel in straight lines at high speeds

Question 30

what is electromagnetic radiation

Answer 30

is the propagation of wavelike energy without mass through space or matter

Question 31

Particulate radiation (alpha and beta)

Answer 31

- alpha: positive helium atoms as a result of radioactive decay from radioactive element (two protons and two neutrons) ○ Lower penetrating power (a sheet of paper - deadly if ingested or inhaled) - Beta: similar to electrons, penetrate about 1.5 cm into skin

Question 32

Common characteristics of all energies on spectrum (electro)

Answer 32

- Have no mass or weight, no electrical charge, travel at the speed of light, travel as a wave - Different measurable energies (frequencies and wave lengths) - Ionizing - high-energy radiations (cosmic rays, gamma rays, and X-rays) capable of ionization

Question 33

Photons

Answer 33

- Bundles of energy that move in wave pattern at the speed of light - Waves are characterized by wavelength and frequency that correlates with the energy the photon has

Question 34

wave concept

Answer 34

- Wavelength is the distance between the crest (peak) of one wave and the crest of the next - Shorter, higher frequency waves have stronger penetration power

Question 35

X-radiation, X-rays, X-ray photons (dental radiation)

Answer 35

- X-radiation: High-energy, ionizing electromagnetic radiation - X-rays: weightless bundles of energy without an electrical charge that travel in waves with a specific frequency at the speed of light - X-ray photons: interact with the materials they penetrate and cause ionization

Question 36

Characteristic production of radiation

Answer 36

- E- displaces an electron, another electron is attached to the empty spot, radiation is produces - Minor source of dental radiation - Energy of radiation is equal to the energy difference between one electron jumping into the empty space

Question 37

Bremsstrahlung production of radiation

Answer 37

- Breaking action of a near miss: (most dental radiation), some radiation is created with a direct hit to the nucleus - Many different energy levels - Mostly used in X-rays