Chapter 2 Radiation: Types, Sources, and Doses Received Flashcards
is the emission of energy in the form of electromagnetic waves or as moving subatomic particles (protons, neutrons, beta particles, etc.) passing through space from one location to another.
Radiation
Some types of radiation produce what
damage in biologic tissue, whereas others do not.
Some sources of radiation are considered what
natural
They are always present in the environment
natural
what else is considered sources of radiation
human-made
sources are created by humans for specific purposes
human-made
contribute a percentage of the total amount of radiation that humans receive during their lifetime
both sources
- natural
- human made
the ability to do work—that is, to move an object against resistance
energy
How does radiation relates to energy
Radiation refers to energy that passes from one location to another and can have many manifestations. This means that many types of radiation exist.
Mechanical vibration of materials
ultrasound
waves, electric and magnetic fields fluctuate rapidly as they travel through space.
electromagnetic wave.
What are some examples of electromagnetic wave
- Radio waves
- Microwaves
- Infrared
- Visible light
Examples of ultraviolet
- xrays
- gamma rays
The full range of frequencies and wavelengths of electromagnetic waves
Electromagnetic spectrum
Electromagnetic waves are characterized by their
- frequency
- wavelength
This form of radiation can travel through space in the form of a wave but can interact with matter as a particle of energy called a photon
Dual nature of electromagnetic radiation (wave-particle duality)
number of cycles per second
frequency
have no mass but have energy
photons
removal of an electron
ionizations
what travel at the speed of light in a vacuum
electrons
To study radiation protection, the electromagnetic spectrum can be divided into two part
- Ionizing radiation
- Nonionizing radiation
x-rays, gamma rays, and high-energy ultraviolet radiation [energy higher than 10 ev)
Ionizing radiation
can transfer sufficient energy to some orbital electrons to remove them from the atoms to which they were attached
- the foundation of the interaction of x-rays with human tissue
Ionizing radiation
ultraviolet radiation [energy less than 10 eV ], visible light, infrared rays, microwaves, and radio waves) and MRI
Nonionizing radiation
does not have sufficient kinetic energy to eject electrons from atoms
Nonionizing radiation
removal of electrons
ionizing radiation
biological tissue damage
ionizing radiation
- Conversion of atoms to ions
- Makes tissues valuable for creating images
- Has the undesirable result of potentially producing some damage in the biologic material
ionization
The amount of energy transferred to electrons by ionizing radiation is the basis of the concept of
radiation dose
Form of radiation that includes alpha particles, beta particles, neutrons, and protons
Particulate Radiation
- heavy form
- most damaging
- ejected from atoms at high speed
Particulate Radiation
- All these are subatomic particles that are ejected from atoms at very high speeds.
- They possess sufficient kinetic energy to be capable of causing ionization by direct atomic collision
- No ionization occurs when the subatomic particles are at rest.
Particulate Radiation
is a naturally occurring process in which unstable nuclei relieve that instability by various types of spontaneous nuclear emissions, one of which is the emission of charged particles.
- changes the chemical makeup
radioactive decay
are emitted from nuclei of very heavy elements, such as uranium and plutonium, during their radioactive decay.
Alpha particles,
- Each contains two protons and two neutrons.
- Are simply helium nuclei (i.e., helium atoms minus their electrons)
- Have a large mass (approximately four times the mass of a hydrogen atom) and a positive charge twice that of an electron
Alpha Particles
are less penetrating than beta particles
- They lose energy quickly as they travel a short distance in biologic matter
- Considered virtually harmless
- As an internal source of radiation, they can be very damaging
- If emitted from a radioisotope deposited in the body, such as in the lungs, alpha particles can be absorbed in the relatively radiosensitive epithelial tissue and are very damaging to that tissue
- superficial of skin
- more biological damage
Alpha particles