Chapter 9 Stochastic Effects And Late Tissue Reactions Flashcards
Late effects are the long term results of radiation exposure, some examples of measurable delayed biologic damage are:
Cataracts
Leukemia
Genetic mutation
Cataracts are considered to be a late tissue reaction that is __________.
Non random
Leukemia and genetic mutations are viewed as delayed __________ or ________ consequences.
Stochastic
Random
Science that deals with the incidence, distribution, and control of disease in a population
Epidemiology
Consist of observations and statistical analysis of data, such as the incidence of disease within groups of people.
Epidemiologic studies
Aka tumor I genesis is the formation of cancer.
Carcinogenesis
Is the name used for a substantial group of diseases in which healthy cells have been transformed into nonstandard cells that divide uncontrollably.
Cancer
The most significant late stochastic effect caused by exposure to ionizing radiation.
Cancer
Is demonstrated graphically through a curve that maps the observed effects of radiation exposure in relation to the dose of radiation received.
Radiation dose response relationship
The DR curve is either ______(straight line) or _______ (curved to some degree), and it depicts either a __________ dose or a ___________ dose.
Linear
Nonlinear
Threshold
Non-threshold
Defined as a point or level which a response or reaction to an increasing stimulation first occurs
Threshold
_________ effects begin to occur only when the threshold dose is reached.
Biologic
_____ relationship indicated that a radiation absorbed dose of any magnitude has the capability of producing biologic effect.
Non threshold
A ____________ , biologic effect responses will be caused by ionizing radiation in living organisms in a directly proportional manner at any dose above zero.
Linear non threshold
_________ proclaims that no radiation dose can be considered absolutely “safe”, with the incidence of the biologic effects increasing directly with the magnitude of the absorbed dose
Linear non threshold (LNT)
The Biological Effects of Ionizing Radiation (BEIR) studied atomic bomb survivors concluded that most stochastic effect and hereditary effect at ______ dose levels from ____ LET radiation.
Low
Low
Low dose from low LET radiation used in diagnostic radiology, appear to follow a ________________.
Linear quadratic non threshold dose response curve.
Implies that the equation that best fits the data has components that depend on dose to the first power and also on dose squared.
Linear quadratic
In 1990, the BEIR committees revised risk estimates indicated that the risk from radiation exposure was about ____ to _____ times greater than previously projected.
3 to 4
The use of a __________ curve of radiation dose response is used for most type of cancers.
Linear non threshold
The linear quadratic non threshold DR curve displays a more __________dose response outcome of low level radiation.
Conservative
What health concerns are presumed to follow the linear quadratic non threshold curve (LQNT).
Leukemia
Breast cancer
Heritable damage
Acute reactions from significant radiation exposure, such as skin erythema and hematologic depression, may be demonstrated graphically through the use of a radiation __________.
Linear threshold dose response curve
_________ curve of the radiation dose response relationship is generally employed in radiation therapy to demonstrate the high dose cellular response to the radiation absorbed doses within specific tissue such as skin, the lens of the eye and various types of blood cells.
The sigmoid, or S shaped (non linear), threshold curve.
The sigmoid curve, the _______ of the curve indicated that limited recovery occurs at lower radiation doses and at the highest radiation doses the curve gradually levels off and then veers downward because the effected living specimen or tissue dies before the observable effect appears.
Tail
When living organisms that have been exposed to radiation sustain biologic damage, the effects of this exposure are classified as__________
Somatic effects
The classification of somatic effects may be subdivided into: __________ and ________
Stochastic effect and tissue reactions
In ________ effects, the probability that the effect occurs depends upon the received dose, but the severity of the effect does not.
Stochastic
The occurrence of a cancer is an instance of a _________ or random somatic effect.
Stochastic
A __________ effect is an effects in the offspring of the individual who was irradiated.
Non somatic
Example of a __________ effect is the irradiation of an individual’s genetic material (sperm of eggs) leading to a genetic malformation in offspring.
Non somatic
Are consequences of radiation exposure that appear months or years afterwards.
Late somatic effects
Late effects may be either ________ or ______ reactions.
Stochastic
Tissue
Cataract formation, fibrosis, organ atrophy, loss of parenchyma cells, reduced fertility and sterility are examples of _______ reactions.
Late tissue
Are effects of radiation on the embryo-fetus in utero that depend on the fetal stage of development and radiation dose received.
Teratogenic effects
Embryonic, fetal, or neonatal death
Congenital malformations, decreased birth weight, disturbances in growth and of development, increased stillbirths, infant mortality, childhood malignancy, childhood mortality are examples of what effects.
Teratogenic effects
Cancer and genetic (hereditary) effects are examples of ______ effects.
Stochastic
______ effects such as the occurrence of cancer are generally determined at the time of irradiation.
Stochastic
No conclusive proof currently exists that low LET ionizing radiation absorbed doses below ______ Gy (10 rads) causes significant increase in the risk of malignancy
0.1
Sources of such _______ radiation include the following:
X-ray and radioactive materials used for diagnostic purposes.
Employment related exposures in medicine and industry
Natural background exposure
Low level
Low level low LET radiation dosage has been defined as an equivalent dose of ______ or less delivers over a short time.
0.1 Sv
