RAD 111 Electromagnetic and particulate radiation

Who is the scottish physicist and mathematician responsible for theory of EM radiation?

James Maxwell

Em Spectrum from low to high

Radiowaves- radio stations and MRI

Microwaves- cell phones , heating food

Infrared light- signal between remote and TV

Visable light- colors visible to the human eye

Ultraviolet light- higher energies, tanning beds

X-rays- medical imaging

Gamma rays- Nuc med

Which EM radiation is able to ionize atoms?

X-rays- medical imaging

Gamma rays- Nuc med

All EM Radiation characteristics

-Has no mass

-Carries energy in waves of electric and magnetic disturbances through space

-Travels at the speed of light

PROPERTIES OF x and gamma photons

-Ionize

-Cannot be focused, refracted, or reflected

-Can be collimated, filtered, absorbed and remitted

-Cannot be seen, heard, felt, or smelled

-Cause certain materials to fluoresce

-Travel at the speed of light

Ionize

high energy

A method of ordering or grouping the EM radiations

-Energy

-Wavelength

-Frequency

WAVE-PARTICLE DUALITY of EM Radiation

properties of both a wave or a particle depending on its energy and possibly environment.

Usually all Em radiation is based on

ave characteristics

Lower energy EM radiation behaves more like

a wave

Higher energy EM radiation behaves more like

a particle

When interacting with tissue, x-rays behave more like

particles

X-ray particles are referred to as

photons

How are photons measured

Electron volts (eV)

X-ray particles move like waves because

they have a wavelength and frequency

EM radiation has wave characteristics of transmission but

-They can burn the skin

-Intensity varies according to distance

-They can ionize matter

WAVE CHARACTERISTICS OF EM RADIATION

-Velocity

-Amplitude

-Wavelength

-Frequency

Velocity

= speed

Velocity of all EM radiation is

the speed of light OR 3x10^8 m/s

Amplitude

Maximum height of wave.

- Not important for EM radiation

Wavelength

- angstrom or one tenth-billionith or nanometer

- measure of the peak of one wave to the peak of the next

- described as long or short

1 angstrom =

0.1 nanometer

Frequency

- Hz or one cycle per second

-Number of waves that pass a given point per second- described as high or low (rate at which the wave repeats itself)

Longer wavelength means

less energy

Shorter wavelength means

more energy

Because all EM radiation travels at the same velocity

relationship between wavelength and frequency is inverse

As wavelength becomes longer, frequency becomes

lower

Which wave would be associated with the higher KVP?

Shorter wavelength with higher frequency

Which wave has more penetrating power?

Shorter wavelength due higher energy

Velocity =

requency x wavelength

Frequency =

velocity/wavelength

Wavelength =

velocity/frequency