Week 2 Lecture Objectives

Question 1

Direct Current

Answer 1

Electrons flow in one direction

Question 2

Alternating Current

Answer 2

Electrons travel in one direction, stops, reverse and go in the opposite direction.

Question 3

Filament Circuit

Answer 3

Provides source of electrons by heating the filament

3-5 volts, controlled by (Ma)

Question 4

High Voltage Circuit

Answer 4

Provides voltage required to accelerate electrons to anode at high speeds.
65,000-100,000 volts
Controlled by (Kv)

Question 5

Transformer Step Down

Answer 5

Heats the filament circuit.
Controlled by Ma
Lots of coils in primary to less coils in secondary.
Goes from 110 to 3-5 volts

Question 6

Transformer Step Up

Answer 6

Controls the high voltage circuit by (Kv)
Less coil in primary to more coils in secondary.
110 Volts to 65,000-100,000 Volts

Question 7

Auto Transformer

Answer 7

Ability to alter Kv

single same amount of coils throughout serves as the primary and secondary coils

Question 8

Quantity

Answer 8

# of x-ray photons in a beam 
controlled by Ma

Question 9

Quality

Answer 9

the Energy/penetration ability of x-ray photons

kVp

Question 10

Distance

Answer 10

The size of the Beam

Question 11

Rate

Answer 11

Exposure Time,influences Quantity

Question 12

Beam Intensity

Answer 12

Quality and Quantity together

Question 13

mA and Kvp relationship with exposure time

Answer 13

Inversely related

KVP/mA goes up exposure time goes down

Question 14

Inverse Square Law

Answer 14

As one variable increases the other decreases
if a distance is double = 1/4 as intense
if a distance is tripled= 1/9 as tense
if a distance is quadruples= 1/16 as intense

Question 15

Short Wavelength

Answer 15

Greater penetration
High energy
High frequency
Goes through body

Question 16

Long Wavelength

Answer 16

Lower penetration
Low energy
Low frequency
Absorbed

Question 17

Which wavelength is better? short or long

Answer 17

SHORT

Question 18

Half Value Layer

Answer 18

Located in tubehead thickness of absorbing material, usually aluminum. necessary to reduce x-ray intensity by 1/2

Question 19

Primary Radiation

Answer 19

Penetrating x-ray beam produced at the tungsten target of the anode that exits at the tube head.

comes out from machine before it touches anything

Question 20

Secondary Radiation

Answer 20

Created when the primary beam interacts with matter.
soft tissue head,bone of skull and teeth

beam interacts with matter, goes passes through body

Question 21

Scatter Radiation

Answer 21

x-ray photon deflects from its path by interaction with matter.

Question 22

Absorbed Completely (photoelectric effect)

Answer 22

Absorbed Completely, energy transfer from photon to matter
Produce light/ white areas on film
ex: enamel, cortical bone, metallic fillings

Question 23

What is “pass through” in secondary radiation?

Answer 23

No interaction
Producing dark areas on film
ex: soft tissue, pulp, PDL

Question 24

Compton Scatter

Answer 24

Photon strikes loosely outer shell electrons, ejecting some from obit. x-ray photon loses energy, goes in another direction
ex: film is foggy

Question 25

Coherent Scatter

Answer 25

Low energy photon path altered by matter, changes direction but no energy transfer

Question 26

Attenuation

Answer 26

Reduction in intensity of x-ray beam

Question 27

Radiopaque Area

Answer 27

High absorption white area on film

Question 28

Radiolucent Area

Answer 28

Low absorption of x-ray photons, black area on film

Question 29

What has affects on absorption

Answer 29

Wavelength, Density, Thickness, Atomic number of material

Question 30

Milliamperage (mA)

Answer 30

Regulates temp of cathode

determines the number of photons in a beam

Question 31

Kilovolt Peak (kVp)

Answer 31

Regulates speed/energy of electrons

determines the Energy of each photon penetration ability

Question 32

What are the two circuits necessary for production of x-rays in the x-ray tube

Answer 32

Filament circuit and high voltage circuit