REVIEW OF BASIC RADIATION CONCEPTS Flashcards
What is Radiobiology?
study of the effects of Ionizing Radiation on Biologic Tissue
What is ionizing radiation?
THE PROCESS OF REMOVING AN ELECTRON FROM A TARGET ATOM, THEREBY PRODUCING AN ION PAIR.
What is Radiation?
energy in the form of waves or particles, especially electromagnetic radiation, which includes gamma, x-ray, ultraviolet rays, visible light, and infrared rays and the particles
Energy from radiation is emitted and transferred through what?
Matter
Radiation is also referred to as
Ionizing Radiation
Classifications of Radiation?
Particulate and Non-particulate
Difference between Particulate and Non-particulate
PARTICLUATE:
- Ionizing radiation in the form of particles
- It has mass and charge
- Travels at the speed of light in free space
- Most originates in the nucleus of an atom
- Consists of minute bits of matter travelling with a certain velocity and therefore possessing kinetic energy
NONPARTICULATE:
- radiation in the form of waves
- has NO mass and NO charge
- travels at the speed of light in free space
- has the combined properties of electricity and magnetism
- disturbance consisting of electric and magnetic field components and traveling through space with the speed of light.
What are the 2 types of particulate radiation?
Alpha and Beta particle radiation
Differences between alpha and beta particle radiation
ALPHA:
- do not penetrate matter as easily as other types of Radiation
- has approximately of 4 amu, charge of +2
- best described as doubly ionized helium
- produced by radioactive decay, primarily of heavy atoms
- low penetrating ability
- no medical uses
BETA:
more penetrating than alpha particles
have a mass of 0.00055 amu
has a charge of either -1 or +1
Negatron - negative electron ;produced by radioactive decay
Positron-positive electron; produced by radioactive decay or pair production; used in nuclear medicine, PET studies
What are the sources of human exposure to radiation?
- Natural Environment Radiation
- Man-made Radiation
results in an annual dose of approximately 300 millirem (mrem); occur in natural
background
Natural environment radiation
3 sources of natural environmental radiation
Cosmic Ray
Terrestrial Radiation
Internally Deposited Radionuclides
particulate and electromagnetic radiation emitted by the sun and the stars
Cosmic Ray
- results from deposits of uranium, thorium, and other radionuclides in
the earth
Terrestrial Radiation
mainly potassium 40 are natural metabolites, they
have always been with us and contribute an equal dose to each of us.
Internally Deposited Radionuclides
results in approximately 60 mrem; comes from fallout, diagnostic x-rays and
radiopharmaceuticals contribute to the human exposures.
Man-made Radiation
Sources of man-made radiation
A. Nuclear power generation
b. Nuclear weapon testing/research application
c. Industrial sources
d. Consumer items - watch dials, exit signs, smoke detectors, camping lantern mantle, and airport
surveillance
What are the modes of human exposure to radiation?
Irradiation
Contamination
a general term and may be used to describe exposure to radiation
originating from any source. It may also include all types of radiation.
irradiation
two types of irradiation
External and Internal
specific and indicates that the exposure is due to xrays originating from external source
External radiation
Sources of external radiation
Diagnostic x-ray, Teletherapy, CT-scan,
Fluoroscopy,Nuclear Power Plan
may come from internal contamination. It may result
from inhalation or ingestion of radioactive materials or in some cases from direct absorption through the skin
Internal Radiation
Sources of internal radiation
Brachytherapy, Nuclear medicine
undesired presence of radioactive materials on any substance in concentrations greater than
those which occur naturally so much so as to cause a technical inconvenience or a radiation
hazard cause by spillage or breakage.
Contamination
Sources of contamination
a. Chemical reactions which involves radioactive materials or nuclear reactions that produce
radioactive gases (directly and indirectly)
b. Evaporation, aeration or spilling or radioactive liquids
c. Mechanical manipulations (i.e griding, welding) of radioactive solids
d. Activation of loose particular matter or materials (dust particles) being irradiated or around a
reactor area in general.
What are the different classifications of human exposure to radiation
a. Background radiation exposure
b. Medical Exposure
c. Occupational Exposure
d. Exposure of the members of the general public
main source of exposure for most
people
Background radiation exposure
deals with intentional exposure of patient for diagnostic and
therapeutic purposes by technically qualified medical and paramedical personnel
medical exposure
exposure obtained by an individual (radiation
worker) as a result of the nature of their work particularly in the radiation area.
occupational exposure
exposure which might be
received by individual members of the population, as a result of their visit to a hospital,
or walk by a hospital, or live or work near one where there is a presence of any
radiation sources.
exposure of the members of general public
What are the types of radiation units?
Traditional/custom or old unit (TU/CU)
System International or Standard Units (SI/SU)
What are the 4 units used to express an amount of radiation? (use the SI units)
- Coulumb per kg
- Gray
- Sievert
- Becquerel
- Measure of the ionization of air produced by x-radiation and gamma radiation below 3 million electron
volts. - Defined as the quantity of x-radiation or gamma radiation
Roentgen/ Coulomb per kilogram
Uses of roentgen?
- radiation exposure of intensity in air
- for calibration of xray equipment
Coulomb is the unit for?
electric charge; number of electrons
Kilogram in the C/kg refers to what?
quantity of air
1 R = ___ c/kg
= 2.58 x 10-4
1 c/kg = ___ R
3876
- Used to express absorbed dose
- Unit used to express the patient’s absorbed dose
- Represents a specific quantity of energy absorbed per kilogram of absorber
Radiation Absorbed Dose/ Gray
1 rad = ____ ergs/gram
100
1 rad = ____ Gy or 10^-2 Gy
0.01
1 Gy = ___ rad
100
• Expressed dose equivalence, or the absorbed dose times a quality factor for
personnel radiation monitoring
• Defined as the quantity of any ionizing radiation that has the same biologic
effectiveness of 1 rad of x-ray
Radiation Equivalent Man (rem)/Sievert (Sv)
What is the unit for occupational exposure for radiation workers?
rem/Sv
Unit that produces the same biologic effect as 1 Gy of high energy x-ray
rem/Sv
1 Sv = __ rem
100
1 rem = ___
0.01 Sv
• It is the amount of radioactivity in a radioactive material and not the
radiation emitted by the material.
• Unit used for radioactivity in Nuclear Medicine
Curie/Becquerel
1 mCi = ____ MBq
37
1 dps = ___ Bq
1
Percentage of sources of radiation exposure?
88% natural
12% Artificial
In the percentage of artificial exposure to radiation, what is the percentage covered of medical radiation?
11%
What are the different medical sources of radiation?
Diagnostic Radiology
Cardiovascular Interventional Radiology
Nuclear Medicine
Radiation Oncology
