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86 terms

Intro To Radiography Basic Radiation (outline)

the ability to do work
Law of Conservation of energy
energy can be converted from one form to another but can be neither created nor destroyed
Kinetic Energy
the energy of motion
Potential Energy
energy stored due to an object's position or arrangement
Chemical Energy
energy from chemical reactions
Electrical Energy
result of an electron or electronic charge passing through an electric potential
Thermal Energy
result of atomic or molecular motion
Nuclear Energy
result of energy contained in the nucleus of an atom
Radioactive Energy
energy emitting from the nucleus
Electromagnetic Energy
an electric and magnetic disturbance traveling through space at the speed of light
Anything that takes up space and has mass.
a measure of the gravitational force exerted on an object; its value can change with the location of the object in the universe
Einstein's equation proposing that energy has mass; E is energy, m is mass, and c is the speed of light
the transfer of energy by waves moving through space
referring to matter that intercepts radiation and absorbs part or all of it; exposed
Ionizing radiation
radiation that can dislodge electrons from atoms to form ions
Man Made Radiation
medical xrays, nuclear medicine, consumer products and nuclear power are examples of what type of radiation
Naturally Occuring Radiation
-cosmic rays
-terrestrial radiation (rocks, buildings)
-inside human body
-radon in the air
300 mrem
how much radiation you are exposed to being alive per year
5 rem
Limit of rems allowed each year
Equator at Sea Level
where is the best place to live because vanhalen belts and atmosphere belts are protecting you
pertaining to the body
cancer and genetic defects are examples of what
Describes biologic radiation effects that are predictable and their intensity is does-dependent. These effects occur only after a certain threshold amount of exposure has been received
Pertains to transmitted hereditary characteristics because of radiation
As Low As Reasonably Achievable
LET-Linear Energy Transfer
____ is a measure of the rate at which energy is transferred from ionizing radiation to soft tissue.
LD 50/30
Lethal dose for 50% of the population over 30 days
LD 50/60
the amount of radiation necessary to kill 50% of a population within 60 days
Discovery of X-ray
November 8, 1895 Wilhelm Conrad Roentgen
Production of captured shadow images on photographic film through the action of ionizing radiation passing through the body from an external source
procedure for viewing the interior of the body using x-rays and projecting the image onto a television screen
Potential Difference
difference in electric potential (voltage) between two points
a unit of measurement equal to 1000 volts
The movement of electric charge; the flow of electrons through an electric circuit.
energy made available by the flow of electric charge through a conductor
1/1000 of an ampere
Exposure time
is directly proportional to the number of electrons crossing the tube and is therefore directly proportional to the number of x-rays created
Roentgen unit
measures exposed based on ionization of air
Unit of measurement used for radiation dosage
1 Roentgen unit
2.08X10(9th) ion pairs/cm(3) equal what
2.58X10(-4) C/kg (81 unit)
radiation absorbed dose
1 Rad
10 mGy=?
1 Gray
100 rad=?
this equals Rad X QF=DE (dose equivalent)
1 Seivert (Sv)
100 rem=?
This = absorbed dose X qualifying factor
Radiation equivalent man
biological absorbed dose and how damaging
QF for x-ray, gamma ray. and beta radiation
QF for thermal nertrons
QF for alpha particles
QF for slow neutrons
QF for medium neurtrons
QF for fast neutrons
a unit of radioactivity equal to the amount of a radioactive isotope that decays at the rate of 37,000,000,000 disintegrations per second
Electron Volt
A unit for expressing the kinetic energy of subatomic particles; the energy acquired by an electron when it is accelerated by a potential difference of 1 volt; equals 1.6 x 10⁻¹² erg or 23.1 kilocalories/mole (abbreviation: eV).
Unstable element
when the number of neutrons greatly out numbers the number of protons that means what?
Alpha particle
a positively charged atom that is released in the disintegration of radioactive elements and that consists of two protons and two neutrons
Beta particle
a proton or neutron that spontaneously changes itself and a new particle is created
If a particle loses a proton it changes its what
Atomic mass
If a particle loses a neutron it changes its what
come from the nucleus of unstable atom
produced within electron clouds
Exposure rate X time
Time exposure=?
reduce time to make low as possible
make as much of this between you and the rays as possible
(inverse square law)
Shielding/protective barriers
you do this to patients and ourselves to protect us
Primary barrier
lead in walls and under table in the central beam
Secondary barrier
helps to prevent scatter and leakage of radiation, lead doors, glass
Fixed or movable barriers
any lead that moves
Benefit over weighs risk
benefit of image should always out weigh risk of exposure
2.5 mm Al equivalent
this is what cuts down the amount of photons to parts of the body
Skin Distance
at least 15 inches between tube and skin
NCRP (national council of radiological protection)
they come up with the radiation limits for occupational dose limits, and non occupational limits
5 rem (50 mSv)
NCRP Stochastic effect (annual) for occupational is what
15 rem (150 mSv)
NCRP Nonstochastic effect for lens of eye for occupational is what
50 rem (500 mSv)
NCRP Nonstochastic effect for all other body parts other than the lens for occupational is what
1(x age in years) rem or 10(x age in years) mSv
Lifetime cumulative exposure
.5 rem for 9 months of year
pregnant worker limited by embryo/fetus dose limits
.5 rem (5.0 mSv)
NCRP Effective dose limit for infrequent exposure for nonoccupational public exposure for a year
.1 rem (1 mSv)
NCRP Effective dose limit for frequent exposure for nonoccupational public exposure for a year
1.5 rem 15 mSv
NCRP Effective dose limit for eye exposure for nonoccupational public exposure for a year
5 rem (50 mSv)
NCRP Effective dose limit for skin and extremity exposure for nonoccupational public exposure for a year
.1 rem (1.0 mSv)
NCRP Effective dose limit for trainees under 18 for nonoccupational public exposure for a year
.5 rem (5 mSv)
NCRP dose for embryo for nonoccupational for total dose
.05 rem (.5 mSv)
NCRP dose for embryo for nonoccupational for 1 month
.001 rem (.01 mSv)
NCRP dose for negligible for nonoccupational