Radiobiology Flashcards
What is radiobiology?
Branch of science concerned with the methods of interaction and the effects of ionizing radiation on living systems
Erythema
Skin redness
Desquamation
The shedding of the outer layers of the skin
Epliation
Hair loss
Who was Clarence Dally and what did he do?
Thomas Edison’s assistantDocumented the side effects of xraysHelped prove the dangers of radiationDied from radiation
Law of Bergonie & Tribondeau (1906)
younger, immature tissues and organs are more radiosensitive than older tissues and organsas the metabolic activity increases within a cell, the more radiosensitive the cell is
Fractionation
give radiation treatment slowly rather than a large dose at one time
Repopulation
ability of normal tissues to replenish themselves following injury
Protraction
time during which a course of radiation is given
Rad
energy ABSORBED in matter from any type of radiation
Rem
unit of DOSE EQUIVALENT of occupational exposure
Roentgen
unit of radiation QUANTITY (measure of ionization of air)
What is a Rad in SI units?
Gray (Gy)
1 Rad = ? Grays
0.01 Grays (Gy)
What is a Rem in SI units?
Sievert (Sv)
1 Rem = ? Sievert
0.01 Sieverts (Sv)
What is a Roentgen in SI units?
Coulomb/kg
What is ICRP?
International Commission of Radiological Protection
What is NCRP?
National Council on Radiation Protection and Measurement
What is the occupational exposure limit per year?
5 rem
What is the cell?
Basic unit of structure and function of all living things composed of a cell membrane, cytoplasm, organelles, and a nucleus -each has a distinct function
Water makes up about what % of a person’s total body weight?
80%
What are somatic cells?
non-sexually reproducing body cells
What are germ cells?
Sexually reproducing cells
What is mitosis?
process of cell division in which the nucleus and the cytoplasm divide to form two identical cells
What is meiosis?
process of cell division for the purpose of reproduction
What is LET?
Linear energy transfer- measure of the rate at which energy is deposited as a charged particle travels through matter (kigher kVp=less energy loss)Diagnostic x-rays have an LET of 3
What is RBE?
Relative biologic effectiveness - A comparison of a dose of test radiation to a dose of 250 keV x-ray that produces the same biological effect (relative effect of LET )As LET increases = RBE increasesDiagnostic x-rays have an RBE of 1
What is OER?
Oxygen enhancement ratio - dose of radiation that produces a given biologic response under anoxic conditions divided by the dose of radiation that produces the same biologic response under aerobic conditions
What is the most critical target of radiation?
DNA
What is LD 50/60?
lethal dose required to kill 50% of the population within 60 days (250-300 rads)
What are the 4 response stages?
prodromallatentmanifestdeath/recovery
What is Bone Marrow Syndrome?
Exposure 200-1,000 RDeath within 10-60 daysReduction of red blood cells, white blood cells, & plateletsDeath results from anemia or infection
What is Central Nervous Syndrome?
exhibited by nervousness, confusion, nausea, vomiting, loss of consciousness and burning sensations of the skin; which are a result of damage to blood vessels and increased intracranial pressure
What is Gastrointestinal Syndrome?
exhibited by nausea, vomiting, cramps and diarrhea as a result of damage to the villi in the small intestine, which leads to a lack of absorption. Dehydration and infection are the result
What are the types of radiation interactions?
coherent scatteringcompton effect/scatteringphotoelectric effectpair productionphotodisintegration
What are the 4 populations that are used as sources of data on the incidence of radiation-induced cancers?
1) atomic bomb survivors2) medically exposed patients3) occupationally exposed personnel4) populations that receive high natural background exposure
Name some radiation induced malignancies.
LeukemiaSkin carcinomaThyroid cancerBreast cancerOsteosarcomaLung cancer
What did Russell do/conclude?
1) radiation is a powerful mutagenic agent2) the majority of mutations are unhealthy to the organism3) there are no unique mutations produced by radiation4) radiation-induced genetic damage can occur as a result of a single mutation
What are the 3 stages of development of the fetus?
Pre-implantationMajor organogenesisFetal or growth stage