Radiation Flashcards
What 3 types of rays are ionizing radiation?
1-UV
2-X-Rays
3-Gamma rays
Radiation with sufficient energy to displace atomic electrons is called what?
Ionizing Radiation
What is the most significant source of Natural radiation?
Radon (37%)
What is the most significant source of Man made radiation?
CT scan (24%)
What are the two types of ionizing radiation?
1-Particulate radiation (a and b particles, neutrons)
2-Electromagnetic radiation/photons (gamma and x rays)
Radiation exposure is measured in what? SI unit then Traditional unit
Coulomb/kilogram (C/kg), Roentgen (R)
Radiation absorbed dose is measured in what? SI unit then Traditional unit
Gray (Gy), rad
Radiation equivalent dose is measured in what? SI unit then Traditional unit
Sievert (Sv), rem
Radiation effective dose is measured in what? SI unit then Traditional unit
Seivert (Sc), (no traditional unit)
Radioactivity is measured in what? SI unit then Traditional unit
Becquerel (Bq), Curie (Ci)
Measuring how much air is ionized within a certain volume by a radioactive source is is called air karma and is useful for what?
Measuring exposure
Linear Energy Transfer (LET) is like what childhood game?
Marbles (a larger or faster object will transfer more energy to smaller objects)
What kind of cells are more affected by radiation as measured by effective dose?
replicating cells
When a photon or secondary electron ionizes a biologic macromolecule it is called what?
Direct Effect (1/3 of the biologic damage from x-rays)
Free radicals and toxins produced through the intermediate step of water radiolysis which then interact with biologic macromolecules is called what?
Indirect effect (2/3 of the biologic damage from x-rays)
What is the primary cause of radiation induced cell death?
Damage to the DNA
Radiation injury dependent on dose with an exposure threshold is called what?
Deterministic Effect (generally tissue related)
What is primarily effected short term by the deterministic effect?
rapidly dividing cells and undifferentiated stem cells
What are the long term effects of irradiation in the deterministic effect?
- loss of parenchymal cells and replacement by fibrous CT
- Loss of capillaries impairing oxygen transport, nutrient transfer and waste removal
What are 4 modifying factors of the deterministic effect?
1-Dose
2-Dose rate
3-Oxygen
4-LET
Radiation injury based on probability of occurrence is called what?
Stochastic effect (No threshold, no level with zero risk)
What are the 2 guiding principles of Radiation safety?
1-justification
2-ALARA (as low as reasonably achievable)
How far away should you stand from the radiation source when taking a radiograph?
at least 2 meters (at 90-135 degrees)
