Flashcards in Final Exam Deck (75)
What are the two ways of measuring radiation?
Old school units and SI Units
What are old school units (4)?
What are SI units (4)?
Coulombs per kilogram (C/kg)
Roentgen (R) is equal to
Coulombs per kilogram (C/kg)
What is the conversion rates of old school (e.g. rad) to SI unites (e.g. Gy)?
1 old school = 0.01 SI unit
100 old school = 1 SI unit
E.g. 1 rad = 0.01 Gy; 1 REM = 0.01 Sv; 1 curie = 0.01 becquerel
Quality factor (QF) is derived from what measurement?
Relative Biological Effectiveness (RBE)
* it varies with different types of radiation
What is the quality factor for X-ray photons
What is the quality factor for gamma photons
What is the quality factor for beta particles
What is the quality factor for thermal neutrons
What is the quality factor for fast neutrons
What is the quality factor for alpha particles
What are the Laws of Bergonie and Tribondeau (4)?
Cell sensitivity depends on:
- Age (young more sensitive)
- Differentiation (simple cells more sensitive)
- Mitotic rate (rapidly dividing cells more sensitive)
- Metabolic rate ( cells that use lots of energy are more sensitive)
Define “absorbed dose”
Energy absorbed per unit mass at a given point
Define “organ dose”
The probability of stochastic effects (mainly cancer creation) as the absorbed dose averaged over an organ
Define “equivalent dose”
The organ dose corrected by a radio action weighting factor that takes account of the relative biological effectiveness of the incident radiation in producing stochastic effects
Define “effective dose”
A weighted sum of equivalent doses to all relevant tissues and organ with the purpose “to indicate the combination of different doses to several different tissues in a way that is likely to correlate well with the total of the stochastic effects”
What does kerma stand for?
Kinetic energy released per unit mass
Sum of kinetic energy of all charged particles liberated per unit mass
1 Kerma is ~ rad at low energies
SI unit of Kerma = Gy
What kind of effects can be either somatic or genetic?
What is the 10-day rule?
Direct pelvic radiation to fertile females should be done only during the first 10 days of menstrual cycle EXCEPT in emergencies
What is stochastic?
The probability of experiencing the effect is proportional to the exposure volume, but the severity of the effect is not really affected.
“randomly determined; having a random probability distribution or pattern that may be analyzed statistically but may not be predicted precisely.”
What might be the results of a “severe stochastic effect” of exposure to radiography (3)?
Mutagenesis (genetic effects)
Stochastic effects can be either _____ or ______ while nonstochastic effects are limited to ____
Stochastic: Somatic or Genetic
NONstochastic: somatic and seen in larger exposure quantities
Low dose exposure effects fall into what category?
What does nonstochastic mean?
The severity of the effect is proportional to the exposure volume. There is a threshold beneath which effects generally aren’t seen
What falls under the category of nonstochastic short-term effects (3)?
What falls under the category of nonstochastic long term effects (5)?
Loss of parenchymal cells
Reduced fertility, sterility
Radiation exposure in the first 14 days of pregnancy increase risk of: