Introduction To Radiology Flashcards
When would you use a radiograph?
To see inside the body (particularly to see mineralised tissues)
Who first discovered X-rays and when?
Wilhelm Conrad roentgen in 1985
How did wilhelm Conrad roentgen find x rays existed?
Experimenting with a crooks tube inside a light-proof box and discovering an image produces on a nearby photographic plate
Define a radiograph
An image produced by x-rays passing through an object and interacting with:
- photographic emulsion on a film
- sensors on a phosphor plate
When were x-rays first used in dentistry?
1896
Two dental tissues that have a similar mineralisation and in which situation can they be differentiated between?
Dentine and cementum - when there is too much cementum
Example of an extra-oral radiograph
DPT
2 other names for DPT
OPT & OPG
Name 3 types of intra oral radiograph
Periapical
Bite wing
Occulsal
Which type of tissues a more damaged by ionising radiation?
Soft tissues more than hard
How many electrons are in the stable K shell?
2
How many electrons are on a stable L shell?
8
Which stable shell has 18 electrons
M shell
What is the function of neutrons?
A binding agent that holds the repulsive forces between electrons and protons together
Define the atomic number
The number of protons in the nucleus
The number of neutrons in the nucleus is called the..
Neutron number
The atomic mass number = ?
Number of protons + number of neutrons
What is an isotope?
Same atomic number (Z) but different atomic mass (A) due to a different neutron number (N)
What is a radioisotope?
Production of an alpha particle due to an isotope undergoing radioactive disintegration
How many neutrons and protons in an alpha particle?
2 and 2
What is the forbidden zone?
The area in between electron shells where electrons cannot exist
How are electrons removed from an atom?
additional energy input overcomes the binding energy
Define the binding energy
The energy that keeps the electron in the shell
Define ionization
The process of removing an electron from an atom resulting in a positive ion
3 types of radioactive emissions
- alpha particles
- beta particles
- gamma rays
For an alpha particle what is 1-size 2-charge 3-speed 4-the penetration depth
- large
- +ve charge
- slow
- 1-2 mm into tissue
For a beta particle
- size
- charge
- speed
- penetration into tissues
- small
- negative
- fast
- 1-2cm
Gamma rays
- size
- charge
- speed
- penetration into tissues
- no size
- no charge
- very fast speed
- depends upon speed and wavelength how far it can pass through
What are beta particles?
Electrons
What kind of ion is an alpha particle?
A helium ion
What are gamma rays a part of?
The electromagnetic spectrum
What are the x-rays in dentistry identical to?
Gamma rays (with smaller energy levels)
On the electromagnetic spectrum, what’s the most harmful?
The greater the wavelength
Define a photon
A packet of energy
