Radiology Lecture 1: Introduction to Radiology

What year was the first radiograph taken?

1895

What are the two imaging goals of radiology in dentistry?

1. Optimal diagnostic information

2. Minimal patient exposure

What is the balance you need to have in radiology for dentistry? (2)

1. Quality image

2. Radiation exposure

What unit is used as a unit of exposure?

Coulombs/Kilogram (C/kg)

What unit is used as a unit of absorbed dose?

Gray (Gy)

How much is 1 Gy in Rad?

1 Gy = 100 Rad

What unit is used as a unit of equivalent and effective dose?

Sievert (Sv)

How much is 1 Sv in Rem?

1 Sv = 100 Rem

What unit is used as a unit of energy?

Joule

What unit is used as a unit of charge?

Coulomb

What unit is used as a unit of power?

Watt

What unit is used as a unit of current?

Ampere

What unit is used as a unit of potential?

Voltage

What unit is used as a unit of frequency?

Hertz

What is emitting energy in the form of particles or waves called?

Radiation

What type of radiation has moving masses that are sometimes charged?

Particulate Radiation

What type of radiation are gamma and X-rays?

Electromagnetic Radiation

What are discrete packets of energy with no mass and no charge?

Photons

What is the unit used for photons?

Electron volts

What speed do waves travel in?

3 x 10^8 (Light Speed)

How can you calculate wave speed using frequency and wavelength?

Wave Speed = Frequency x Wavelength

What are the four properties of all electromagnetic radiation?

1. No mass/charge

2. Speed of light in vacuum

3. Travels in straight line

4. Behavior depends on energy of photons

What does the energy of photons depend on directly?

Frequency

What does the energy of photons depend on inversely?

Wavelength

At what type of wave does ionizing begin?

Ultraviolet

What type of wave is non-ionizing and thermal?

Microwave

What type of wave is non-ionizing and optical?

Infrared

Which three waves are ionizing and causes broken bonds?

1. Ultraviolet

2. X-Ray

3. Gamma rays

What is the building block of matter?

Atom

What three things are atoms made of?

1. Protons

2. Neutrons

3. Electrons

Why is the nucleus of an atom always positive or neutral?

Made of only protons (+) and neutrons (0)

Do electrons have mass?

No

What is atomic number determined by?

Number of protons

What is the atomic mass determined by?

Protons and neutrons

What condition must be met for an atom to be electrically neutral?

Protons = Electrons

What determines isotopes?

Gain or loss of neutrons

Did anions gain or lose electrons?

Gain

Did cations gain or lose electrons?

Lose

What is the formula to calculate electrons based on the number of layers (n)? (Layers are labeled from K - Q)

2n^2

What is the amount of energy required to remove an electron?

Binding Energy

Is binding energy more for the inner or outer layer?

Inner layer

Is binding energy more for higher or lower atomic number?

Higher