Chapter 2 EXAM 1 Flashcards
Radiation
energy in transit from one location to another
matter
anything that occupies space and has mass
what are the fundamental building blocks of matter
atoms and molecules
what is the scientific unit of mass
kilograms
energy
the ability to do work
energy is measured in radiology using the unit
electron volt
energy is measured in SI unit called
the joule
potential energy
the ability to do work by virtue of position
kinetic energy
the energy of motion
chemical energy
energy released by a chemical reaction
electrical energy
the work that can be done when an electron or an electronic charge moves through an electric potential
thermal energy
heat
energy of molecular motion
nuclear energy
energy contained in the nucleus of an atom
electromagnetic energy
type of energy in xrays, radiowaves, microwaves, infrared light, visible light, ultraviolet light, and gamma rays
electromagnetic energy is also referred to as
electromagnetic radiation
photon
the smallest quantity of any type of electromagnetic energy
travels through space at the speed of light
a photon is also sometimes called
a quantum
speed of light =
186,000 miles per sec..
3*10^8 m/s
electromagnetic radiation appears to have a dual nature called
wave-particle duality
wave-particle duality means
it can travel through space in the form of a wave but can interact with matter as a particle of energy
xrays can be described as both…
waves and particles
types of electromagnetic radiation that comprise the electromagnetic spectrum (7 types)
- radio waves
- microwaves
- infrared light
- visible light
- ultraviolet light
- xrays
- gamma rays
ultraviolet light
has enough energy to destroy bacteria and produce changes in the skin layers
xrays/gamma rays
short wavelengths, high energy, high frequency
capable of ionization.
ionization
removal of an electron from its orbital path
the only difference between xrays and gamma rays
is their origin
all electromagnetic waves have the same
constant speed
electromagnetic waves are different in
wavelength and frequency
wavelength
distance between 2 successive crests or troughs in a wave
frequency
the number of wavelengths passing a point per second
an increase in frequency must always be accompanied by a decrease in
wavelength
frequency is what in proportion to wavelength
inversely proportional
photon energy and frequency are
directly proportional
electromagnetic spectrum is divided into 2 parts
- ionizing radiation
2. nonionizing radiation
ionizing radiation includes
xrays, gamma rays, high energy ultraviolet radiation
has enough energy to eject electrons from atoms
nonionizing radiation includes
low energy ultraviolet radiation
visible light
infrared rays
microwaves and radiowaves
radiation dose
the amount of energy transferred to electrons by ionizing radiation
equivalent dose
a quantity of radiation applying only to ionizing radiation
ionizing radiation can be classified into 2 categories
- electromagnetic radiation
2. particulate radiation
electromagnetic radiation includes
xrays and gamma rays
particulate radiation includes
alpha particles
beta particles
neutrons
protons
particulate radiation refers to
particles originating from radioactive nuclei with the energy to ionize matter
alpha particles, beta particles, protons and neutrons are all
subatomic particles that are ejected from atoms at very high speeds. can cause ionization when in motion but not when at rest.
radioactive decay
naturally occurring process whereby an unstable atomic nucleus relieves its instability by various types of nuclear spontaneous emissions
radioisotope
radioactive atoms that have the same number of protons that are changed into different atomic species
alpha particles are also called
alpha rays
alpha particles
contain 2 protons and 2 neutrons
has a large mass
cause more damage than xrays
alpha radiation from an external source is
nearly harmless
alpha radiation from an internal source can
intensely irradiate the local tissue
if ingested internally you’ll die
an average alpha particle possesses
4 to 7 MeV of kinetic energy
average alpha particle ionizes about
40000 atoms
In air alpha particles can travel
5cm
in soft tissue alpha particles travel
less than 100
beta particles are also called
beta rays
beta particles
light particles w/ atomic mass of 0
one negative or positive charge
cause more damage than xrays but not as much as alpha particles
the only difference between electrons and negative beta particles is
their origin
positive beta particles are called
positrons
what can be used as a shield for alpha particles
piece of paper
what can stop beta particles
a piece of wood
beta particles may traverse how much air
10-100cm of air
beta particles may traverse how much soft tissue
1-2cm of soft tissue
protons
positively charged components of an atom
proton beam therapy uses a special machine called
a cyclotron or a synchrotron to generate and accelerate protons
neutrons
electrically neutral components of an atom
neutron beam therapy uses
neutrons to destroy dense tumors
equivalent dose EqD
radiation quantity used for radiation protection purposes when a person receives exposure from various types of ionizing radiation
attempts to numerically specify the biologic harm produced by different types of radiation
equivalent dose enables the calculation or
effective dose
what is the unit of equivalent dose
Sievert or REM
effective dose EfD
takes into account the equivalent dose and also the fact that our organs have different degrees of radiosensitivity
represents the whole body dose
damage at the atomic level results in
molecular change which can cause cellular damage
if cellular damage is excessive the organism exhibits genetic or self changes for example
mutations
cataracts
leukemia
example of organic damage
changes in blood count
may cause decrease in the number of lymphocytes
blood system is pretty radiosensitive
2 types of sources of radiation
- natural environmental radiation
2. man made radiation
Total EqD from natural radiation
3.0 mSv or 300 mRem
total EqD from manmade radiation
3.3 mSv or 330 mRem
Total EqD from both manmade and natural radiation
6.3 mSv or 630 mRem
natural sources of radiation include
terrestrial radiation
cosmic radiation
internally deposited radionuclides
manmade sources of radiation include
consumer products air travel nuclear fuel nuclear weapons testing nuclear power plant accidents/caused by natural disasters medical radiation
