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MY Radiation Protection > Late Deterministic and Stochastic Radiation Effects on Organ Systems > Flashcards

Late Deterministic and Stochastic Radiation Effects on Organ Systems Flashcards

1
Q

Radiation induced damage at the cellular level that may lead to somatic and genetic damage in the living organism later in life.

A

Late effects

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2
Q

Examples of measurable late biologic damage:

A

cataracts
leukemia
genetic mutations
(cataracts are deterministic, leukemia and genetic effects are stochastic.)

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3
Q

Definition of epidemiology

A

Science that deals with the incidence, distribution, and control of disease in a population.

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4
Q

What consists of observations and statistical analysis of data such as incidence of disease within groups of people?

A

Epidemiology

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5
Q

Early radiation workers and studies of irradiated populations provide proof that:

A

high doses of radiation can induce cancers in humans.

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6
Q

Radiation Dose-Response Relationship:

A

Graph that maps out the effects of radiation observed in relation to the dose of radiation received.

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7
Q

In response relationship graphs, curves can be _______ and depicts _______.

A

linear or non-linear, threshold dose or non-threshold dose.

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8
Q

The Committee on the Biologic Effects of Ionizing Radiation (BEIR) 1980 report stated:

A

The majority of stochastic somatic effects and genetic effects at low dose levels from low LET radiation, appear to follow a linear-quadratic non threshold curve.

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9
Q

The Committee on the Biologic Effects of Ionizing Radiation (BEIR) 1990 report stated:

A

Revised risk estimates indicated that the risk of radiation exposure was about three to four times greater than previously projected.

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10
Q

Currently BEIR Committee recommends:

A

the use of the linear non threshold curve of radiation dose-response for most types of cancer.

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11
Q

The term “linear-quadratic” states that the equation that best fits the data has components that depend on:

A

dose to the first power and also dose squared. The curve estimates the risk associated with low-dose levels from low-linear energy transfer (LET) radiation.

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12
Q

The term “linear non threshold curve” implies that:

A

the chance of a biologic response to ionizing radiation is directly proportional to the dose received.

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13
Q

According to the linear non threshold curve, no radiation exposure is:

A

assumed to be “absolutely” safe.

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14
Q

The linear non threshold curve accurately reflects the effects of:

A

high-LET radiation (neutrons and alpha rays) at higher doses.

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15
Q

Deterministic effects of significant radiation exposure such as skin erythema may be demonstrated graphically throughout the use of:

A

a linear threshold curve of radiation dose-response.

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16
Q

The sigmoid threshold curve is generally employed in radiation therapy to demonstrate:

A

high-dose cellular response to radiation within specific tissues such as skin, lens of the eye, and various types of blood cells. Different effects require different minimal doses.

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17
Q

The tail of the sigmoid curve indicates:

A

limited recovery occurs at lower radiation doses.

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18
Q

At the highest doses, the sigmoid curve gradually levels off and veers downward because:

A

the affected living specimen or tissue does before the observable effect appears.

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19
Q

Non-somatic effects:

A

Would be irradiation of an individual’s genetic material (sperm or eggs) leading to genetic malformation.

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20
Q

Stochastic effects:

A

Mutational or randomly occurring biologic changes, independent of dose, in which the chance of occurrence of the effect rather than the severity of the effect is proportional to the dose of ionizing radiation. These effects occur months or years after high-level, and possibly also after low level, radiation exposure. Also called probabilistic effects.

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21
Q

Deterministic effects:

A

Biologic somatic effects of ionizing radiation that can be directly related to the dose received. These are cell-killing effects that exhibit a threshold dose below which the effects are absent and above which the severity of the biologic damage increases as the dose increases.

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22
Q

Late somatic effects:

A

Consequences of radiation exposure that appear months or years after exposure.

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23
Q

Late somatic effects may result from:

A

Previous whole or partial body acute exposure.
Previous high radiation doses.
Long-term low-level radiation exposure sustained over several years.

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24
Q

Risk estimate for contracting cancer from low-level radiation:

A

No conclusive proof exists that low-level ionizing radiation exposure below .1 Sv (10 rem) cause a significant increase in the risk of malignancy.

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25
Q

Low-level radiation has been defined as:

A

“an absorbed dose of .1 Sv (10 rem) or less delivered over a short period of time” and as “a larger dose delivered over a long period of time - for instance .5 Sv (50 rem) in ten years.”

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26
Q

Lab experiments on animals and studies on human populations exposed to high doses of radiation determined three categories of adverse health consequences:

A

Cancer induction
Damage to the unborn from irradiation in utero
Genetic effects

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27
Q

Cells that survive the initial radiation and then retain a “memory” of that event are responsible for:

A

producing late effects. “Memory” being some form of damage that persists and is passed onto future generations of the cell.

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28
Q

There are three major types of late effects:

A

Carinogenesis
Cataractogenesis
Embryologic effects. (birth defects)

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29
Q

For occupationally exposed personnel and all patients in diagnostic radiology, the risk of cancer is not directly measurable, however, current radiation protection philosophy assumes that:

A

risk still exists and may be determined by extrapolating from high-dose data, where risk has been directly observed, down to low doses, in which it has not been observed.

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30
Q

Absolute risk model:

A

Predicts that a specific number of excess cancers will occur as a result of exposure.

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31
Q

Relative risk model:

A

Predicts the number of excess cancers will increase as the natural incidence of cancer increases with advancing age.It is relative in the sense that it predicts a percentage increase rather than a specific number of cases,

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32
Q

Physical appearance of cancer induced by ionizing radiation does not appear:

A

different than a cancer caused by other agents.

33
Q

Human evidence of radiation carcinogenesis comes from epidemologic sties conducted many years after subjects were exposed to high doses of ionizing radiation. Examples of groups that were studied are:

A

Radium watch-dial painters
Uranium miners
Early medical radiation workers
Patients injected with contrast agent thorotrast.
Infants treated for enlarged thymus gland
Incidence of breast cancer in radiation treatment of benign postpartum mastitis
Children of the Marshall Islanders
Japanese atomic bomb survivors.

34
Q

Radium watch-dial painters suffered from:

A

Osteoporosis
Osteogenic sarcoma
And carcinoma of epithelial lining of nasopharynx and paranasal sinuses.

35
Q

Radium is chemically similar to:

A

Calcium

36
Q

European uranium miners developed :

A

Lung cancer after inhaling radon

37
Q

Navajo uranium miners sustained lethal doses o ionizing radiation by:

A

Breathing radioactive dust and drinking radioactive water.

38
Q

Navajo uranium miners died of:

A

Cancer and respiratory diseases.

39
Q

Navajo miners’ family members:

A

Also developing radiation induced cancers.

40
Q

Early medical radiation workers showed a higher incidence of

A

Aplastic anemia and leukemia.

41
Q

Patients injected with Thorotrast suffered from:

A

Liver and spleen cancer
Angiosarcomas
Biliary duct carcinomas
Extra vascular injections caused tissue surrounding injection site to become cancerous.

42
Q

In the 40’s and 50’s, infants with enlarged thymus glands were treated with therapeutic doses of radiation. This resulted in:

A

development 20 years later of thyroid nodules and carcinoma

43
Q

Radiation treatment of benign postpartum mastitis:

A

531 women received a mean dose of 247 cGy(t), incidences of breast cancer doubled.

44
Q

Fallout from an a-bomb test on Bikni Atoll in March, 1954….the wind shifted and:

A

children on neighboring islands received substantial absurd doses to thyroid from external and internal exposures. This resulted in thyroid cancers.

45
Q

Epidemiologic studies of about 100,000 Japanese A-bomb survivors exposed to 1 Gy or more showed:

A

significant increase in incidence of leukemia. An increase of about 100 fold.

46
Q

Since the late 1940’s and early 1950’s, incidence of leukemia among Japanese Atomic Bomb Survivors has slowly:

A

declined. Leukemia occurs about 2 years after initial exposure, rises to highest level between 7 and 10 years and declines to almost zero at about 30 years.

47
Q

Since the late 1950’s and early 1960’s, occurrence of other radiation-induced solid tumors among Japanese a-bomb survivors have:

A

continued to escalate.

48
Q

Studies of a-bomb survivors provide evidence that radiation induces _____. Incidence rises with dose following which model?

A

breast cancer. Linear non-threshold curve.

49
Q

Studies of female japanese a-bomb survivors indicate a _____ risk of breast cancer of __:1 to as high as __:1.

A

relative risk. 4, 10

50
Q

Radiation dose and radiation-induced leukemia among Japanese a-bomb survivors: A ____ relationship exists between radiation dose and leukemia

A

linear non-threshold

51
Q

Bomb dropped on Hiroshima provided more _____ radiation than _____.

A

gamma, neutron

52
Q

Doses received by people living within 10 miles of Chernobyl:

A

.03 Sv (3 rem) to .12 Sv (12 rem)

53
Q

Because winds carried a plume of radiation in different directions for 10 days following accident and more than 20 countries received fallout, about ______ people received exposure to fallout.

A

400,000.

54
Q

Harvard estimates that about _______ people from around the worse will develop a radiation induced malignancy from Chernobyl.

A

20,000

55
Q

_________ was administered to children in Poland following the Chernobyl incident to block the uptake of Iodine 131 which causes cancer.

A

Potassium iodide.

56
Q

During the first 10 years following the Chernobyl disaster, ______ increased dramatically among children linking in regions where heaviest radioactive iodine contamination occurred.

A

Thyroid cancer

57
Q

Positive outcomes of Chernobyl incident:

A

Local citizens of contaminated territories empowered to make their own decisions to facilitate reconstruction of overall quality of life.
Given authority to manage their own radiologic risk.
Local citizens engage in cooperative problem solving as they reconstruct their environment.

58
Q

Nonspecific life span shortening:

A

Radiation was believed to have accelerated all causes of death as well as the aging process in animals, making them more susceptible to several diseases.

59
Q

What was the actual cause of the early demise of experimental animals in studies of life span post-irradiation?

A

Induction of Cancer.

60
Q

Analysis of epidemiological studies of American radiologists showed shortening of life span in both animals and humans was result of ______ and ______ and not other “nonspecific” causes or accelerated aging.

A

cancer, leukemia

61
Q

In a study initiated in 1982 of approximately 146,000 American RT’s, it was found that techs who started working before 1940 had:

A

a slightly higher risk of dying from any type of cancer. Techs working after 1940 did not demonstrate an elevated risk.

62
Q

In a study initiated in 1982 of approximately 146,000 American RT’s, it was found that techs who started working before 1950 demonstrated a higher risk of dying from:

A

leukemia compared with those who entered the workforce after 1950.

63
Q

The probability that a single dose of radiation of about __ Gy (___ rad) will induce formation of cataracts is high.

A

2, 200

64
Q

A ____ dose as low as ___ Gy has been known to cause cataracts in mice.

A

neutron, .01 (1 rad)

65
Q

Radiation induced cataracts in humans follow a _________ response relationship.

A

threshold, nonlinear dose

66
Q

The three stages of gestation in humans are:

A

Preimplantation (0-9 days after conception)
Organogenesis (10 days to 12 weeks post conception)
Fetal stage (corresponds to term)

67
Q

_____ trimester seems to bet the most crucial period for irradiation of embryo-fetus because:

A

The first, a large number of stem cells are present during this period of gestation.

68
Q

Irradiation of embryo during first 12 weeks of development to EqD in excess of 200 mSv (20 rem) frequently results in:

A

death or causes congenital abnormalities.

69
Q

When a high dose of radiation is received within approximately 2 weeks of fertilization (before the start of organogenesis):

A

prenatal death and usually results in spontaneous abortion.

70
Q

During preimplantation stage, if the fertilized ovum is irradiated with a dose in the range of .005 to .15 Gy(t):

A

embryonic death will occur. Malformations do not occur at this stage.

71
Q

Preimplantation stage occurs when?

A

0-9 days after conception

72
Q

Organogenesis stage occurs when?

A

10 days to 12 weeks after conception.

73
Q

Developing emus is most susceptible to radiation-induced congential abnormalities during this stage:

A

Organogenesis

74
Q

Abnormalities occurring from irradiation during organogenesis may include:

A 
growth inhibition
mental retardation
microcephaly
genital deformities
sense organ damage.
75
Q

The presence of fatal abnormalities in fetus during late stages of organogenesis will cause:

A

neonatal death (death at birth)

76
Q

Keletal damage from radiation exposure occurs most frequently during period from week __ to week __ of development.

A

3, 20.

77
Q

Possible effects of irradiation during the fetal stage include:

A

cancer and functional disorders.

78
Q

fetal radiosensitivity ______ as gestation progresses.

A

decreases.

MY Radiation Protection (5 decks)

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