Ch. 7 Biological Effects from Ionizing Radiation Flashcards
LET
Average energy deposited/unit length
Free radicals
Possess the ability to attack and damage organic molecules
Mitotic delay
The failure of the cell to start dividing on time
Point mutations
Genetic mutations at the molecular level
RBE
Describes the relative capabilities of radiations with various LET’s to produce a particular biologic reaction
Undifferentiated cells
Non-specialized immature cells
Well-differentiated cells
Mature cells specialized in function
QF
Modifying factor - basically a measure of RBE
Hyperbaric oxygen
High pressure oxygen
Stem cells
Immature blood cells
Hypoxic cells
Cells that lack adequate amounts of oxygen
Radiation damage is observed on three levels:
Molecular, cellular, and organic
The effect of ionizing radiation that is most harmful to the human body is the…
Direct effect (takes high LET)
With respect to the law of Bergonie and Tribondeau, what would best complete this statement? “The greatest radiation effects occur in cells having the…”
Most reproductive activity, longest mitotic phases, and least maturity
Which of the following groups of cells are most radiosensitive?
Lymphocytes
Which of the following is considered to be a low-LET radiation?
- X-rays
- Alpha particles
- Gamma rays
x-rays and gamma rays
Ionizing radiation causes complete chromosome breakage when…
Two direct hits occur in the same rung of the DNA macromolecule
What type of cell is least radiosensitive?
Adult nerve cells
OH~ +OH~ =
H2O2
The dose of a reference radiation quality, stated in grays, necessary to produce the same biological reaction in a given experiment that is produced by a dose of the test radiation simply defines:
RBE
While passing through a human cell, an x-ray photon interacts with and inactivates the cell’s master molecule. The consequence to the cell is:
Death
