LECTURE 3 RADIATION SAFETY AND MEASURES Flashcards
Is the radiation with sufficient energy to produce ion, causes damage to living cells. Damage that may be repaired, that may be permanent, or that can cause death to the cells
Ionizing Radiation
Two sources of radiation?
Natural Environmental or background radiation and human-made radiation
3 Natural Environmental or Background Radiation
Cosmic Radiation
Radioactive elements in the earth
radioactive substances
3 Human-made radiation
fallout from nuclear weapons
radioactive materials used in industry
medical and dental x-ray exposure
Medical and dental radiographs and radioactive materials to diagnose and treat disease accounts for __ of the general public’s exposure to human-made radiation
90%
when did roentgen discover xrays
november 8, 1895
In 1964, the congress of the united states chartered the __ as a non-profit corporation
National Council on Radiation Protection and Measurements (NCRP)
National Council on Radiation Protection and Measurements (NCRP) is composed of?
scientific committees
was an attempt to protect consumers from the hazards of radiation-producing electronic products
The Radiation Council for Health and Safety Act of 1968
The bureau also has a limited control program for radioactive materials that are not covered under the jurisdiction of the __
Atomic Energy Commission (AEC)
amount of radiation required to turn skin red
Erythema Dose
Amount of ionizing radiation that produces 1 cubic cm of air, ions that carry electrostatic unit of quality of electricity of either positive or negative charge
Roentgen
In __, roentgen was adopted as the international standard measure of ionization in air
1938
in 1956, __ was established to measure the amount of radiation absorbed by a medium
Radiation Absorbed Dose (RAD)
Unit for measuring the amount of exposure for x-rays and gamma ray
roentgen
unit for measuring absorbed energy from radiation
rad (Gy)
unit for measuring the biological effect from radiation
rem (Sv)
unit of activity in SI system; this measure is used in nuclear medicine studies with the radionuclides, which are sometimes called radioactive isotopes
Becquerel (Bq)
measures the amount of activity known as the radioactive disintegration
Ci
Is in adherence to the radiation protection guides
Effective Dose Equivalent Limit (EDE)
the philosophy underlying the establishment of dose limits is twofold:
- non-threshold concept
- risks-versus-benefits relationship
the basis for NCRP establishment of policies and procedures for radiation exposure
As Low As Reasonably Achievable (ALARA)
What does ALARA stand for?
As Low As Reasonably Achievable (ALARA)
Two groups of dose limit
- radiation workers
- general public
Double helix structure
Deoxyribonucleic acid (DNA)
best pictured as a flexible rope ladder that is twisted in a spiral staircase shape
Deoxyribonucleic acid (DNA)
less than 1% of the cell
Deoxyribonucleic acid (DNA)
when ionizing radiation interacts directly with the DNA molecule, certain breaks can occur in the “rung” of the DNA “ladder”
Direct Hit Theory
they said that stem cells are radiosensitive, mature cells are radioresistant
Bergonie and Tribondeau
they said younger tissues are radiosensitive
Bergonie and Tribondeau
white blood cells
Lymphocytes
most radiosensitive cells
Lymphocytes
is the time between the initial irradiation and the occurrence of any biologic change
Lantent Period
It is the total body response to large dose received over a short time period and that is characterized by short term biologic effects
Acute Radiation Syndrome
2 categories of long term effects
- somatic effects
- genetic effects
occur in general body cells that involve all the body functions except sexual reproduction
somatic effects
these effects include cancer, cataracts, and the life-span shortnening
somatic effects
occur in germ cells, which are responsible for sexual reproduction
genetic effects
the effect the occur within the germ cell are transmitted to future generations and are therefore not evident to the individual in which they initially take place
genetic effects
Are produced whenever a stream of high speed electrons hits the atoms of a metal target in an x-ray tube
X-ray
any alteration in the structure or amount of DNA
mutation
2 sources of exposure
- X-ray
- Radionuclides
secondary radiation emitted from the interaction of x-rays with matter; generally lower in energy, with a directional distribution that depends on the energy of the incident radiation
Secondary Radiation/ Scattered Radiation
an incident x-ray beam
Primary Radiation
controls the quality of xray beam
Kilovoltage (Kv)
controls the quantity of radiation produced and functions inside the tube
Milliamperage (mA)
is used for the treatment of patients with cancer in radiation therapy or oncology; it is also used in the field of nuclear medicine
radionuclides
naturally existing radionuclide found in uranium ore
radium
is a human-made radionuclide
cobalt 60
3 methods of protection from external radiation
time
distance
shielding
the exposure factor of kilovoltage, time, and distance are directly related to the amount of radiation exposure a patient receives
exposure factors
states that the intensity of the beam is inversely proportional to the square of the distance
Inverse Square Law
another factor that affects patient exposure
filtration
are used to absorb the scattered radiation that is created by the interaction of the primary radiation with matter before this scatter reaches the image receptor
Grid
restriction of the primary beam to a limited area
Collimation
are also beam restricting devices that can be attached to the tube housing
Cones and Diaphragms
include restraining devices, technique charts, and a quality control program
Repeat Exposures
general term that describes both the female and male reproductive organs
Gonad
suspended over the patient’s gonad area to absorb radiation from the primary beam
shadow shield
most useful in AP and PA projections but is not suited for protection during fluoroscopy
shadow shield
made for tabletop use
stand-type shadow shield
strips of lead-impregnated material; most suitable for AP and PA projections
Flat contact shield
used by men
Shaped contact shield
cuplike shield to cover the scrotum and penis
Shaped contact shield
gloves and aprons
Personnel Protection
lead goggles
Personnel Protection
lead apron
Personnel Protection
most often used during personnel monitoring
optically stimulated luminescent dosimeter (OSL)
highly accurate and more appropriate than the film badge for some radiation monitoring tasks
Thermoluminescnet Dosimetry (TLD)
