Biology of radiation Flashcards
Sources of radiation?
1-Background (natural)
2-Manmade (artificial)
Dental radiation makes how much % of all manmade radiation?
0.26%
what is radiation biology?
a branch of biology that is concerned with the effects of ionizing radiation on living tissues and organisms.
who are the irradiated study populations?
1-atomic bomb survivors
2-workers exposed to radioactive materials (radium watch dial painters)
3-nuclear power plants accidents (Chernobyl)
4-patient undergoing radiation therapy (they are less because the radiation is area specific and not whole body)
recent studies show that radiation workers in nuclear industries who have suffered low doses of radiation approximated to that of CT scan, and atomic bomb survivors who received low doses approximate to those from CT scans
interaction of radiation with atoms?
9%= no interaction
7% coherent scattering (nowadays it is filtered)
27%=photoelectric effect
57%= Compton scattering
mechanism of radiation injury are?
1-direct action
2-indirect action
what happens to atom in direct action of radiation?
the ionized atom has a positive charge and it is chemically active trying to replace the missing electron..
what happens if the ionized atom is a part of a larger molecule?
it will cause braking of the molecular bonds
what will happen if enough molecules are damaged in direct action of radiation?
1-loss of cell function
2-didruption of cell organelles
3-death of cell
what is the (critical biomolecular target) for radiation?
the DNA
So by breaking molecular bonds, radiation has a DIRECT EFFECT on the cell
what is the percentage of direct action of radiation?
20%
what is the chemical effect of indirect radition?
radiolysis of water
-mechanism is mostly via chemical effect
in the indirect action, which by product of the chemical reaction is the most dangerous?
H2O2 caused by free radicals
hydrogen peroxide.