Introduction To Radiology

Question 1

When would you use a radiograph?

Answer 1

To see inside the body (particularly to see mineralised tissues)

Question 2

Who first discovered X-rays and when?

Answer 2

Wilhelm Conrad roentgen in 1985

Question 3

How did wilhelm Conrad roentgen find x rays existed?

Answer 3

Experimenting with a crooks tube inside a light-proof box and discovering an image produces on a nearby photographic plate

Question 4

Define a radiograph

Answer 4

An image produced by x-rays passing through an object and interacting with:

• photographic emulsion on a film
• sensors on a phosphor plate

Question 5

When were x-rays first used in dentistry?

Answer 5

1896

Question 6

Two dental tissues that have a similar mineralisation and in which situation can they be differentiated between?

Answer 6

Dentine and cementum - when there is too much cementum

Question 7

Example of an extra-oral radiograph

Answer 7

DPT

Question 8

2 other names for DPT

Answer 8

OPT & OPG

Question 9

Name 3 types of intra oral radiograph

Answer 9

Periapical
Bite wing
Occulsal

Question 10

Which type of tissues a more damaged by ionising radiation?

Answer 10

Soft tissues more than hard

Question 11

How many electrons are in the stable K shell?

Answer 11

2

Question 12

How many electrons are on a stable L shell?

Answer 12

8

Question 13

Which stable shell has 18 electrons

Answer 13

M shell

Question 14

What is the function of neutrons?

Answer 14

A binding agent that holds the repulsive forces between electrons and protons together

Question 15

Define the atomic number

Answer 15

The number of protons in the nucleus

Question 16

The number of neutrons in the nucleus is called the..

Answer 16

Neutron number

Question 17

The atomic mass number = ?

Answer 17

Number of protons + number of neutrons

Question 18

What is an isotope?

Answer 18

Same atomic number (Z) but different atomic mass (A) due to a different neutron number (N)

Question 19

What is a radioisotope?

Answer 19

Production of an alpha particle due to an isotope undergoing radioactive disintegration

Question 20

How many neutrons and protons in an alpha particle?

Answer 20

2 and 2

Question 21

What is the forbidden zone?

Answer 21

The area in between electron shells where electrons cannot exist

Question 22

How are electrons removed from an atom?

Answer 22

additional energy input overcomes the binding energy

Question 23

Define the binding energy

Answer 23

The energy that keeps the electron in the shell

Question 24

Define ionization

Answer 24

The process of removing an electron from an atom resulting in a positive ion

Question 25

3 types of radioactive emissions

Answer 25

1. alpha particles
2. beta particles
3. gamma rays

Question 26

For an alpha particle what is 
1-size 
2-charge 
3-speed 
4-the penetration depth

Answer 26

1. large
2. +ve charge
3. slow
4. 1-2 mm into tissue

Question 27

For a beta particle

• size
• charge
• speed
• penetration into tissues

Answer 27

• small
• negative
• fast
• 1-2cm

Question 28

Gamma rays

• size
• charge
• speed
• penetration into tissues

Answer 28

• no size
• no charge
• very fast speed
• depends upon speed and wavelength how far it can pass through

Question 29

What are beta particles?

Answer 29

Electrons

Question 30

What kind of ion is an alpha particle?

Answer 30

A helium ion

Question 31

What are gamma rays a part of?

Answer 31

The electromagnetic spectrum

Question 32

What are the x-rays in dentistry identical to?

Answer 32

Gamma rays (with smaller energy levels)

Question 33

On the electromagnetic spectrum, what’s the most harmful?

Answer 33

The greater the wavelength

Question 34

Define a photon

Answer 34

A packet of energy