Lec 3 Classification of Biologic Effects Flashcards
2 types of biologic effects
Stochastic Effect
Deterministic Effect
Stochastic effect or deterministic effect?
No threshold dose
Stochastic effect
Stochastic effect or deterministic effect?
Cell killing
Deterministic Effect
Stochastic effect or deterministic effect?
Sublethal DNA damage
Stochastic effect
Stochastic effect or deterministic effect?
Caused by doses used in diagnostic radiology.
Stochastic effect
TRUE OR FALSE
A single x-ray photon has the potential to cause a DNA mutation
TRUE
TRUE OR FALSE
Even the smallest radiation dose could cause a heritable effect or cancer.
TRUE
Stochastic effect or deterministic effect?
Manifest only when the radiation exposure to an organ or tissue exceeds a threshold level.
Deterministic Effect
Stochastic effect or deterministic effect?
The higher the dose, the more severe the effect.
Deterministic Effect
Stochastic effect or deterministic effect?
Severity of clinical effects is independent of dose; all-or-none response an individual either manifests effect or does not.
Stochastic effect
TRUE OR FALSE
Dental radiography has low to no deterministic effect.
TRUE
TRUE OR FALSE
Deterministic effect are tissue reactions.
TRUE
TRUE OR FALSE
Stochastic effect are caused by cell killing.
FALSE
TRUE OR FALSE
Deterministic effect manifest only when the radiation exposure exceeds a THRESHOLD level.
TRUE
2 subdivisions of Stochastic effect?
- Radiation-induced cancer
- Heritable effects
2 types of cell killing?
- Mitotic death
- Apoptosis
TRUE OR FALSE
Radiation-induced cancers are clinically and histologically the same from sporadically occurring or chemical-induced cancers.
FALSE
Radiation-induced cancers are clinically and histologically INDISTINGUISHABLE from sporadically occurring or chemical-induced cancers.
Examples of tissues / organs that are more sensitive to carcinogenic effects of ionizing radiation.
- Female breast
- Thyroid gland
TRUE OR FALSE
There is a long latent period, ranging from years to decades, between radiation exposure and the occurrence of cancer.
TRUE
TRUE OR FALSE
The risk of radiation-induced tumor induction is approximately threefold higher in children than in adults.
TRUE
Examples of radiation-induced cancers.
- Leukemia
- Thyroid cancer
- Salivary gland tumors (Warthin tumor)
- Breast cancer
- Brain and nervous system cancers
Changes seen in the offspring of irradiated individuals.
Heritable effects
Consequence of DNA damage in germ cells.
Heritable effects
TRUE OR FALSE
Studies of the children of patients who received radiotherapy show NO detectable increase in the frequency of genetic diseases
TRUE
Most common means of cell killing.
Mitotic death
Mitotic death is explained by the law of?
The Law of Bergonié and Tribondeau
Cell radiosensitivity to killing = ________ / _________
Mitotic rate / Degree of differentiation
Rapidly dividing cells will be more ____________ and postmitotic specialized cells will be most __________.
- radiosensitive
- radioresistant
Programmed cell death.
Apoptosis
__________ are an exception to Bergonié and Tribondeau’s law.
Lymphocytes
The most radiosensitive mammalian cell.
Lymphocytes
__________ of the salivary glands are highly radiosensitive.
Serous acini
TRUE OR FALSE
Embryos and fetuses are more radiosentitive than adults.
TRUE
The deterministic effects on embryos and fetuses depends on _______ and _______ during irradiation.
- dose
- gestational age
Irradiation during preimplantation (0 to 9 days in humans) causes ___________.
The threshold for this effect is estimated to be __________.
In comparison, the dose to an embryo and fetus from natural background radiation is approximately __________ during the 9 months of gestation.
Fetal irradiation is associated with __________ (irradiation at 8 to 15 weeks gestation) and _____________ (irradiated at 8 to 25 weeks’ gestation).
- embryonic death
- 100 mGy
- 0.5 to 1 mSv
- microcephaly; mental retardation
