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 or artificial
what contributes 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
emitted from nuclei/ nucleus
- if you ingest it is very damaging to your internal organs
Alpha particles
- Identical to high-speed electrons except for their origin
- 8000 times lighter than alpha particles and have only one unit of electric charge (−1)
beta particles
two units of electric charge (+2)
alpha particles
- Will not interact as strongly with their surroundings as alpha particles do.
- Capable of penetrating biologic matter to a greater depth than alpha particles with less ionization along their paths
beta particles
occurrs when a nucleus relieves instability by a neutron transforming itself into a combination of a proton and an energetic electron
beta particle
Alternative sources of high-speed (high energy) electrons are commonly produced in a radiation oncology treatment machine called
linear accelerator
will penetrate more deeply and therefore cannot be stopped by ordinary pieces of paper.
beta particles
can be stopped by paper
alpha particles
can be stopped by lead
gamma and x-rays
To treat superficial skin lesions in small areas
- To deliver radiation boost treatments to breast tumors at tissue depths typically not exceeding 7 to 8 cm
Require either millimeters of lead or multicentimeter thick slabs of wood to absorb them
For energies of less than 2 meV, either a 1-cm thick block of wood or a 1-mm thick lead shield would be sufficient for absorption
linear accelerator
- Positively charged components of an atom
- Have a relatively small mass that, however, exceeds the mass of an electron by a factor of 1800
- Number of protons in the nucleus of an atom constitutes its atomic number, or Z number
Protons
- Electrically neutral components of an atom
- Have approximately the same mass as a proton
neutrons
If two atoms have the same number of protons but a different number of neutrons in their nuclei, they are referred to as
isotopes
If one of these combinations of Z protons and some neutrons leads to an unstable nucleus, then that combination is called
- nuclear medicine
radioisotope
the amount of kinetic energy per unit mass that has been absorbed in a material due to its interaction with ionizing radiation
- measured in units of milligray (mGy)
- tissue or matter
Absorbed dose
- Takes into account the type of ionizing radiation that was absorbed
- Provides an overall dose value that includes the different degrees of tissue interactions that could be caused by different types of ionizing radiation
- Measured in units of the millisievert (mSv)
- 1/1000th of a sievert
Equivalent dose (EqD)
- Takes into account the dose for all types of ionizing radiation (e.g., alpha, beta, gamma, x-ray) to various irradiated organs or tissues in the human body (e.g., skin, gonadal tissue, thyroid
- Intended to be the best estimate of overall harm that might be produced by a given absorbed dose of radiation in human tissue
- Measured in units of the millisievert (mSv)
- It takes into account both the type of radiation and the part of the body irradiated.
Effective Dose (EfD)
Ionizing radiation primarily causes
biologic damage
Produced by ionizing radiation while penetrating body tissues primarily by ejecting electrons from atoms composing the tissues
Biologic Damage Potential
Result of destructive radiation interaction at the atomic level start where and end where
- Molecular change
- Cellular damage
- Organic damage
leading to abnormal cell function or even complete loss of cell function
cellular damage
Changes in blood count
- nonnegligible exposure to ionizing radiation
organic damage
Sources of ionizing radiation
- Natural
- Human-made (artificial)
Dose from natural background radiation is approximately
3.1 mSv annually
Annual dose from medical radiation is approximately
2.3 mS
Annual dose from human-made radiation is approximately
0.1 mSv annually
Annual dose from natural background radiation is approximately
3.1 mSv
Annual dose from all-natural, medical and human-made radiation is approximately
5.5 mSv
remains constant unless an accident happens
natural radiation
components of natural radiation:
- Terrestrial radiation
- Cosmic radiation
- Internal radiation from radioactive atoms
examples radon and thoron
terrestrial radiation
examples solar and genetic
cosmic radiation
radioactive atoms also called radionuclides
internal radiation
gases emit alpha particle radiation
radon
- It behaves as a free agent that floats around in the soil
- gas into the lower levels of homes through cracks or holes in the foundation, and then the gas may permeate upward as it decays and becomes solid particles
- that 2.3 mSv of natural background radiation exposure comes primarily from the gaseous radionuclide,
- over 4 have to get ligation system
- 33% of background
radon
grows more substantial because of accidental or deliberate human actions such as mining radioactive elements
enhanced natural sources
Ionizing radiation created by humans for various uses is classified as
Human-made (artificial) radiation
- Consumer products containing radioactive material
- Nuclear fuel for the generation of power
- Atmospheric fallout from nuclear weapons testing
- Nuclear power plant accidents
- Nuclear power plant accidents as a consequence of natural disasters
- Medical radiation
human-made, or artificial, radiation
Consumer products and devices containing radioactive materia
Airport surveillance scanning systems
* Electron microscopes
* Ionization-type smoke detector alarms
* Industrial static eliminators
results from the use of diagnostic x-ray machines and radiopharmaceuticals in medicine
Medical radiation
The two largest sources of artificial radiation are
- Radiography and Fluoroscopy
- Computed Tomography (CT) procedures
Accounts for approximately 2.3 mSv of the average annual individual EfD.
- Exposure to human-made radiation in medical applications continues to increase rapidly
Medical radiation
Because of the large variety of radiologic equipment and differences in imaging procedures and in individual radiologist and radiographer technical skills, patient dose for each examination varies according to the facility providing imaging services.
medical radiation
The amount of radiation received by a patient from diagnostic x-ray procedures may be indicated in terms of the following
- Entrance skin exposure (ESE), which includes skin and glandular dose
- Bone marrow dose
- Gonadal dose
blood changes is how many SV
0.25 sv
nausea, and diarrhea, how much sv
1.5 sv
erythema (redness)
2.0 sv
if dose to to gonalds, temporary sterility
2.5 sv
50? chance of death lethal dose of 50%
3.0 sv
what is death sv
6.0 sv
have higher energy
higher frequency
- shorter wavelenth (packed together)
gamma rays and x-rays ultraviolet
lower enegry
lower frequency
higher longer wavelength
radio microwaves
The atomic number of an element is determined by
the number of protons in the nucleus of an atom of that element;
what charge are electrons
negative charge
what charge are protons
positive charge
wha charge are neutrons?
neutral
atomic number is represented by what letter
Z
examples of particulate radiations
- alpha particles
- beta particles
- nuetrons
- protons
The recommended action limit for radon in homes is
4 pCi/L of air.
alpha particle is stopped by what
paper
beta particle is stopped by what
plastic
gamma and x-rays are stopped by what
lead
electrons origin is
outside the nucleus
alpha and beta origin is from
the nucleus
x-rays have in reference to energy and wavelength and frequency
^ energy ^ frequency decreaase wavelengh(short)
