Radiation Biology Flashcards
What do the free radicals from the indirect effects of radiation combine to produce?
Hydrogen peroxide
What is ionizing radiation?
Enough energy to remove tightly bound electrons from the orbit of an atom.
What is a low energy incident photon?
Its energy is well below the binding energy of the electron.
T/F Dental X-rays make up a high percentage of ionizing radiation sources.
false – it only makes up 0.26% of the artificial (non-background) radiation sources.
Mitosis rate and radiosensitivity are ______ related.
(directly / inversely)
directly
Of the following, which one is NOT considered highly radiosensitive:
a) bone marrow
b) muscle cells
c) intestines
d) mucous membranes
b) muscle cells have a low sensitivity
What types of cells have intermediate radiosensitivity?
Fine vasculature, growing cartilage, growing bone, salivary glands, thyroid gland, lungs, kidney, liver
What types of cells have a low radiosensitivity?
Mature erythrocytes, muscle cells, neurons
What are the types of interactions of x-rays with matter and what percent are they?
No interaction – 9%
Coherent scattering – 7%
Photoelectric absorption – 27%
Compton scattering – 57%
What are the two categories for biological effects of radiation?
Deterministic
Stochastic
In the deterministic effects of radiation, ______ increases as the absorbed dose increase.
Severity
In the stochastic biological effects of radiation, _____ increases as the absorbed dose increases.
Probability
What are some examples of DNA damage?
- change or loss of a base
- breakage of a single DNA strand
- breakage of both DNA strands
- cross linking of DNA strands to other DNA strands or proteins
What biological effect of radiation is dependent on a high dosage?
Deterministic
What is radiosensitivity?
the relative susceptibility of cells, tissues, organs, or organisms to the harmful effects of ionizing radiation
