Nature of Radiation

Energy

The ability to do work

What is the international system (SI) for energy?

Joule (J)

what is the international system (SI) of mass?

Kilogram

Potential energy

the ability to do work by virtue of position

kinetic energy

the energy that is in motion (moving car, turning windmill wheel)

Chemical energy

Energy released by a chemical reaction

Electrical energy

Represents the work that can be done when an electron moves through an electric potential difference (voltage. Househould energy)

Thermal energy (heat)

The energy of motion at the molecular level

Nuclear energy

The energy that is contained within the nucleus of an atom (nuclear power plants, atomic bomb)

Electromagnetic energy

the most important in the world of radiology

what does electromagnetic energy include?

gamma rays, x-rays, radiowaves, microwaves

Einstein mass-energy equivalence

E=mc^2

What does E stand for? E=mc²

Energy

What does M stand for? E=mc²

Mass

What does C stand for? E=mc²

the velocity (speed) of electromagnetic radiation (light) in a vacuum

Radiation emitted from the sun is called?

electromagnetic radiation

Irradation

matter that intercepts radiation and absorbs part or all of it

Examples of irradation

Spending a day at the beach, radiographic exams

What is radiation?

the transfer of energy

Ionizing radiation

any radiation that is capable of removing an orbital electron from the atom with which it interacts with

The only form of electromagnetic radiation with sufficient energy to ionize

x-rays, gamma rays, ultraviolet rays

Ionizing radiation that can injure humans is in two categories?

ubiquitous background radiation and human made radiation

Ubiquitous background radiation

cosmic rays, terrestrial radiation, internally deposited radionuclides, radon

What is responsible for most of our background radiation?

Radon

Ex of Human made radiation

CT, X-ray, fluoro, smoke detectors, watches tobacco, tv

The most significant source of human made radiation is?

Diagnostic and interventional medical radiation

What does NRCP stand for?

National Council of Radiation Protections and Measurements

What is energy is ever present, all around us?

electromagnetic energy

What is the only small segment of electromagnetic energy naturally apparent to us?

Visible light

Who called an atom of light a photon

Greeks

is a photon an atom?

No

What is the smallest quantity of any type of electromagnetic energy?

Photon

How fast does a photon travel?

At the speed of light

An x-ray photon is a?

Quantum electromagnetic energy

What is a quantum?

A small bundle of energy

James clerk Maxwell

The first to discover that light has both electric and magnetic properties (19th century)

Formula for the speed of light

3×10^8 m/s or 186,000 m/s

Properties of photons

No mass, have electric and magnetic fields that are continuously changing in a sinusoidal fashion, can be demonstrated as a sine wave

What relationship does frequency and wavelength have?

Inverse proportional

Frequency

Is the number of wavelengths that pass a point of observation per second

What are the following formulas used for? Velocity = frequency x wavelength, C = λ x f

Used for both sound and electromagnetic energy

Wavelength

In the distance from one crest to another

Three regions that are important in radiologic science

Visible light, X-ray and gamma rays, radio frequency

Photons represent a bundle of energy but differ in

Frequency and wavelength

Diagnostic ultrasound requires

requires Matter (gel used for image)

The unit for X-rays is

Electron volt (eV)

The only difference between X-ray and gamma rays is

Their origin. X-rays are emitted from an electron cloud of an atom, gamma rays are from inside of the nucleus of a radioactive atom

Visible light photons behave like

Flowing waves

X-ray photons behave more like

Zooming particles

Wave particle duality of electromagnetic energy

Visible light photon behave like waves, X-ray photons behave like particles