Radiation Biology Flashcards
What is the risk of developing cancer?
40%
What is the study of the effects of particulate and electromagnetic radiation, including ionizing radiation, on living systems?
Radiation Biology
Absorbed dose of radiation is measured in _____.
Grays (Gy)
Equivalent dose is measured in _____.
Sievert (Sv)
_____ is based on the amount of damage that can be done to the body.
Quality Factor (QF)
Rem = _____ X ______
rad X QF
1 Sv = _____
100 rems
____ is used to estimate radiation risks so that the risks from different types of radiologic examinations as well as background radiation can be compared to one another.
Effective dose
____ takes into consideration the differing radiosensitivities of the various tissues of the body as well as the tissue weighting of the area exposed and is used to compare the risks from partial body exposures.
Effective Dose
_____ is the sum all weighted equivalent doses in all the irradiated tissue determined by using tissue weighing factors; this is a calculated estimate and is calculated in Sieverts.
Effective dose
____ is the dose adjusted for impact, body volume, and tissue sensitivity.
Effective dose
What effects does X-rays have inside the body?
Indirect ionizing- 2/3 of DNA damage (strikes DNA and causes a single or double stranded break)
Direct attack
What is the event sequence in radiation injury low dose effects?
absorption of radiation –> ionization/radical formation –> chemical alteration –> enzymatic repair or development of lesion
What are effects where the risk is proportional to the dose?
stochastic effects
____ implies that there is no threshold.
Stochastic effects
Cancer due to genetic mutations in somatic cells or heritable effects due to genetic mutations in germ cells are examples of _____.
Stochastic effects
____ are effects where severity is proportional to the dose.
Deterministic effects
_____ implies that there is a threshold.
Deterministic effects
Harmful tissue effects (e.g. in utero birth defects), cataracts, radiation burns of the skin are examples of ______.
Deterministic effects
True or False? Deterministic effects DO NOT occur as a result of normal dental radiologic examinations.
True
What is the permanent change in genetic in the genetic material of a cell resulting in a change of information passed on to progeny ( cell or organism )?
mutations
True or False? There is a spontaneous mutation background level for all organisms.
True
True or False? Radiation increases incidence of mutations.
True
True or False? No mutations are radiation specific.
True
True or False? Radiation is a weak mutagen.
True
True or False? Currently, no evidence for a threshold.
True
True or False? No expression of germ cell mutations have been observed in humans due to radiation effects.
True
True or False? There is no statistically significant increase in genetically related disease in the children of A-Bomb survivors.
True
What is the principle consequence of radiation?
Induction of cancer
True or False? Cancer is a multi-step process with many stages.
True
What are the three possible mechanisms for radiation carcinogenesis?
- cancer results from radiation-induced somatic mutations
- radiation activates latent carcinogenic virus in cells
- radiation acts indirectly by creating conditions in the body favoring growth of tumors
What are the three parts of the Law of Bergonie and Tribondeau?
Most sensitive cells are those that:
- have a high mitotic rate
- undergo may future mitoses
- are most primitive in differentiation
What are 6 factors that influence cells response to irradiation?
- stage of cell cycle at time of exposure
- cell repair processes
- oxygen concentration
- protectors and sensitizers
- dose/dose rate
- radiation LET
What is the average energy released from ionization and excitation to absorbing medium per unit track length?
Linear Energy Transfer (LET)
True or False? X-rays = Low LET.
True
True or False? Alpha particles/neutrons = high LET.
True
True or False? 100 Gy –> death in 1 to 2 days (Cerebrovascular syndrome).
True
True or False? 10 Gy –> death in 5 to 10 days (Gi syndrome).
True
True or False? 2 to 5 Gy –> death in 3 weeks (Hematopoietic Syndrome).
True
True or False? 2 Gy –> Transient Erythema (hours).
True
True or False? 10 Gy –> Dry Desquamation.
True
True or False? 15 Gy –> Moist Desquamation.
True
True or False? Females less than 10 yo is 6X more likely to develop fatal cancer than 50 yo.
True
Name four in-utero effects of radiation.
- intrauterine death
- growth retardation
- developmental abnormalities
- cancer in childhood
True or False? Radiation from dental x-rays can produce birth defects.
False
