Biological Effects Flashcards
4 phases of cell cycle:
M, G1, S, G2
Cell phase(s) where there is a gap in cell growth
G1, G2
Cell phase where there is DNA synthesis and the molecule is replicated to two molecules
S
4 phases in M phase:
Prophase
Metaphase
Anaphase
Telophase
Phase in M phase where DNA swells, takes structural form
Prophase
Phase in M phase where Chromosomes appear and line up
Metaphase
Phase in M phase where Chromosomes split
Anaphase
Phase in M phase where Chromosomes become mass of DNA
Telosphase
In ___ a second division without duplication of chromosomes occurs
Meiosis
2 categories of human sensitivity to radiation:
- organ sensitivity
- cellular radiosensitivity
Cellular radiosensitivity depends on 2 things:
- rate of proliferation (how quickly the cells mature)
- state of development of the cells (how differentiated or undifferentiated they are)
Lymphocytes, spermatogonia, erythroblasts, intestinal crypt cells are ___ radiosensitive
highly
Endothelial cells, osteoblasts, spermatids, fibroblasts have ___ radiosensitive
Intermediate
Muscle cells, nerve cells have ___ radiosensitivity
low (radioresistant)
Tissues with high radiosensitivity require __ - __ Gy to cause change in cells.
2-10
Tissues with intermediate radiosensitivity require __ - __ Gy to cause change in cells.
10-50
Tissues with low radiosensitivity require > __ Gy to cause change in cells.
50
Lymphoid, bone marrow, and gonads are ___ radiosensitive
highly
Skin, GI tract, cornea, growing bone, kidney, liver, and thyroid have ___ radiosensitivity
intermediate
Muscle, brain, and spinal cord have ___ radiosensitivity
low
Law of B andT says: Radiosensitivity of cells is ___ proportional to their reproductive activity and ___ proportional to their degree of differentiation (specialization)
directly, inversely
Less specialized cells and cells with high metabolic rate are ___ sensitive to radiation
more
LET
linear energy transfer
rate at which energy is transferred from ionizing radiation to tissue
LET
RBE
Radiobiological Effectiveness
As LET increases, RBE ___
increases
the higher the RBE, the ___ the radiosensitivity
higher
dose delivered over a period of time
Protraction
dose delivered in discrete fractions
Fractionation