Radiology 1

Question 1

What are the two key pieces of legislation in place regulating the use of Ionising radiation?

Answer 1

1. Ionising Radiation regulations 2017
2. Ionising Radiation (Medical Exposure) Regulations 2017 - IRE(ME)R 2017

Question 2

What is a radiograph?

Answer 2

An image produced by x-rays passing through an object and interacting with the photographic emulsion on a film. If a digital image is being formed, the x-rays affect a sensor or phosphor plate.

Question 3

Atomic number

Answer 3

Protons

Question 4

Neutron number

Answer 4

neutrons

Question 5

Atomic mass number

Answer 5

neutrons + protons

Question 6

Isotopes

Answer 6

atom with the same protons, different neutrons

Question 7

Alpha particles

Answer 7

2 protons + 2 neutrons (helium nucleus)
Size: large
Charge: positive (+ve)
Speed: slow
Penetration: 1-2mm in tissue
Energy: 4-8 MeV
Damage potential: extensive ionisation

Question 8

Beta particles

Answer 8

Electrons (fast electrons)
Size: small
Charge: negative (-ve)
Speed: fast
Penetration: 1-2 cm in tissue
Energy: 100keV - 6MeV
Damage potential: ionisation

Question 9

Gamma rays

Answer 9

Electromagnetic radiation
Size: Nil
Charge: Nil
Speed: very fast
Penetration: can pass through tissue
Energy: 1.24 keV - 12.4 MeV
Damage potential: ionisation

Question 10

What type of x-rays are used in dentistry?

Answer 10

Identical to gamma rays - with lower energy values.
No charge, weight or mass.
Very fast.
Cause ionisation.

Question 11

Energy is measured in…

Answer 11

electron volts - eV

Question 12

Frequency is measured in…

Answer 12

Cycles per second or Hertz

Question 13

Wavelength is measured in…

Answer 13

metres or nanometers = 10 -9

Question 14

Visible light range

Answer 14

400-700nm

Question 15

What is a volt?

Answer 15

The SI (System internationale) unit of electric potential difference is the volt.

Question 16

What is 1 volt?

Answer 16

The potential difference between 2 points on a conducting wire, carrying a constant current of 1 amp, when the power dissipated between the points is 1 watt.

Question 17

How can voltage be thought of conceptually?

Answer 17

The “power” or “force” that causes a current to move along a wire or electrons to move across a gap from a cathode to an anode.

Question 18

What is happening when electricity is flowing through a wire?

Answer 18

Electrons within the wire coils are vibrating, this produces heat, wire becomes red hot giving off light.

Radiant heat warms air molecules resulting in warming effect.

Heat produced is proportional to current and voltage.

Question 19

X-rays in terms of energy conversion

Answer 19

Electricity is converted into x-ray generation (slightly inefficient as much of the conversion of energy produces heat).