RT206-Module1

RADIATION

- It is energy that is emitted or transferred in the form of electromagnetic waves or energetic, high-speed particles

FORMS OF RADIATION

Particulate Radiation

Electromagnetic Radiation

Particulate Radiation

It consists of fast-moving subatomic particles with mass and energy

Electromagnetic Radiation

It is produced by electric and magnetic disturbances in space that travel in vacuum with the velocity of light, resulting in a wavelike motion

- It is known to be massless, and behaves both as a wave or as a particle

examples of Particulate Radiation:

Alpha Particles

Beta Particle

Electron

Protons

Neutron

Alpha Particles

Consists of two protons and two neutrons (nuclei of Helium atoms) in close association

Beta Particle

-Small and fast-moving, and more penetrating than an alpha particle

Electron

-Small, negatively charged particles that can be accelerated to high energy to a speed close to that of light

Protons

-Positively charged particles and are relatively massive (2,000 times greater than an electron)

neutron

Particles with a mass similar to protons but it has no electrical charge

Negatron

a negatively charged electron, produced by nuclear disintegration

Positron

a positively charged electron, produced by pair production

Types of Electromagnetic Radiation:

Non-ionizing Radiation

ionizing Radiation

Non-ionizing Radiation

-Found at the long wavelength end of the electromagnetic spectrum, and may have enough energy to excite molecules and atoms

ionizing Radiation

Has more energy than non-ionizing radiation, enough to cause chemical changes by breaking chemical bonds

SOURCES OF RADIATION

Natural-occurring (background) radiation

Man-made (artificial) radiation

Natural-occurring (background) radiation

Low levels of ionizing radiation that are naturally occur from the surroundings

Man-made (artificial) radiation

Levels of radiation as a product of human innovation and activities

CLASSIFICATION OF HUMAN EXPOSURE TO RADIATION

Occupational Exposure

Medical Exposure

Public Exposure

Occupational Exposure

Obtained as a result of the nature of their work

Medical Exposure

Intentional radiation exposure for diagnostic and therapeutic purposes

Public Exposure

- Exposure which might be received from neither work or a medical procedure

MODES OF HUMAN RADIATION EXPOSURE

Irradiation

Contamination

Irradiation

A general term that may be used to describe exposures to radiation from any sources

Contamination

Undesired presence of radioactive materials or sources on any substance in concentrations greater than those which occur naturally

RADIATION UNITS AND QUANTITIES

Activity

Absorbed dose

Equivalent dose

Effective dose

Activity

It is the number of radionuclides disintegrating per second

Absorbed dose

- It accounts for the amount of energy deposited in a mass

Equivalent dose

- It accounts for the biological effects for different types of radiation

Effective dose

- It measures the biological effect of a particular type of radiation on organs or tissues

Radiation Weighting Factor

- It is a dimensionless variable, providing an estimate of relative human hazard from different types of radiation energies

Tissue Weighting Factor

It is a dimensionless variable used to account for the different sensitivities of different organs and tissues