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Know the difference between Fractionation and Protraction,and the benefits of them.
Fractionation-A dose delivered in smaller equal doses
Protractionation-A dose delivered continuously over a specific period of time.
What is the difference between Linear and Nonlinear and what both look like on a chart?
Linear-Direct relationship beteween response and dose(Straight Line)
What is the difference between Threshold and Non-threshold and what both look like on a chart?
Threshold-Refers to the point at which a response to radiation first occurs
Non-Threshold-dose response will begin to occur at any dose regardless of size
Why fractionation and protraction benefit the patient during radiation therapy?
Causes less effect b/c time is allowed for intracellular repair and tissue recovery.
When humans are most radiosensitive during their
Before birth and when older
What is the curve that has a radiation response at any given dose?
What is LET and it's characteristics?
Linear Energy Transfer-Measure of the rate at which energy is transferred from ionizing radiation to soft tissue/
Expressed in units of kiloelectron volt
What is RBE and it's characteristics?
Relative Biologic Effectiveness
Average 250 kVp
What are the DX values for LET and REB
What is the law of Bergonie and Tribondeau?
The radiosensitivity of living tissue varies with maturation and metabolism.
PG 513, 33-1
What is hormesis?
An idea tgat a little bit of radiation is good for you. By stimulating hormonal and immune responses to other toxic environemntal agents(ALARA)
What conditions are tissue more radiosensitve?
When irradiated in an oxygenated (aerobic) states
Hormesis PG 515-516
What is the relationship between LET and RBE?
As LET increases the ability to produce biologic damage increases.
What are the characterisitics of x-radiation?
What method expresses radiation quality?
It is expressed by LET
Fundamentals Principals Radiation Biology