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Flashcards in Radiology Chapter 5&6 Deck (58)
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1

symptoms of the short-term radiation effects after a massive dose of ionizing radiation

Acute radiation syndrome (ARS)

2

Adopted as a culture and attitude by professionals who work with ionizing radiation to minimize radiation exposure and risks

ALARA

3

the theory that radiation-exposed tissues accrue damage and may function at a diminished capacity with each repeated exposure

cumulative effect

4

when the severity of the change is dependent on the dose

deterministic effect

5

states that cell damage results when ionizing radiation directly hits critical areas within the cell

direct theory

6

graph produced when radiation dose and the resultant biological response are plotted

dose response curve

7

cells contained within the testes and ovaries, containing the genes

genetic cells

8

radiation effect that is passed on to future generations

genetic effect

9

change in the genetic material of a cell that passes from one generation to another

genetic mutation

10

states that cell damage results indirectly when x-rays cause the formation of toxins in the cell such as hydrogen peroxide. Toxins in turn cause the cell damage
formation of ion pairs

indirect theory

11

formation of ion pairs

ionization

12

the exposure of an object or a person to radiation. Term can be applied to radiations of various wavelengths, such as infrared rays, ultraviolet rays, x-rays, and gamma rays

irradiation

13

: following exposure to radiation, injury that results in damage that is not repaired during the recovery period. May give rise to later long-term effects of radiation exposure

irreparable injury

14

: the time between exposure to radiation and the first clinically observable symptoms. Latent means hidden

latent period

15

states that the radiosensitivity of cells and tissues is directly proportional to their reproductive capacity and inversely proportional to their degree of differentiation

law of B and T

16

amount of radiation that is sufficient to cause the death of an organism

lethal dose

17

a graph showing the relationship between the dose of exposure and the response of the tissues, indicating that any amount of radiation, no matter how small, has the potential to cause a biological response

nonthreshold dose response curve

18

radiation-induced changes that follow the latent period

period of injury

19

ionization can dissociate water within a cell into hydrogen and hydroxyl radicals that have the potential to recombine into new chemicals such as hydrogen peroxide. These new chemicals act as toxins to the body, causing cellular dysfunction. Considered an indirect effect of radiation exposure

radiolysis of water

20

refers to a substance or tissue that is not easily injured by ionizing radiation

radioresistant

21

refers to a substance or tissue that is relatively susceptible to injury by ionizing radiation

radiosensitive

22

period following exposure to radiation, where some healing can take place

recovery period

23

the chance or likelihood of adverse effects or death resulting from exposure to a hazard

risk

24

any body cells except the reproductive cells

somatic cells

25

when radiation affects all body cells except the reproductive cells

somatic effect

26

when a biological response is based on the probability of occurrence rather than the severity of the change

stochastic effect

27

a graph showing the relationship between the dose of exposure and the response of the tissues, indicating that there is a “threshold” amount of radiation, below which no biological response would be expected

threshold dose response curve

28

Inventors of Law of B and T

Bergonie and Tribondeau

29

radiosensitive cells from high sensitivity to low sensitivity

white blood cells (lymphocytes)
red blood cells (erythrocytes)
immature reproductive cells
epithelial cells
connective tissue cells
bone cells
nerve cells
brain cells
muscle cells

30

somatic effect occurs when

biological change/damage occurs in irradiated individual, not passed to offspring

31

genetic effect describes

changes in hereditary material does not effect irradiated individual, but future generations

32

factors that determine radiation injuries

total dose
dose rate
area exposed
variation in species
individual sensitivity
variation in cell sensitivity
variation in tissue sensitivity
age

33

critical tissues for dental radiography in head and neck region

mandible (red bone marrow)
lens of eye
thyroid gland
possibly the hypothalamus-pituitary-thyroid combination

34

studies of occupational workers exposed to chronic low levels of radiation have shown

no adverse biological effect

35

x-rays ionize water, resulting in

formation of free radicals, which recombine to form toxins

36

many body cells (somatic cells) have a recovery rate of

almost 75% during the first 24 hours

37

determining whether or not an exposure is potentially harmful, a radiographer should consider

the quantity and the duration of exposure and which body area to be irradiated

38

genetic cells cannot

repair themselves

39

the primary cause of biological damage from radiation is

ionization

40

direct injury from radiation occurs when the x-ray photons

strike critical cell molecules

41

indirect injury from radiation occurs when the x-ray photons

ionize water and form toxins

42

according to the law of B and T, cells with a high reproductive rate are described as

radiosensitive

43

what cells are most radiosensitive?

white blood cells

44

what cells are most radioresistant?

muscle cells

45

when the effect of radiation exposure is observed in the offspring of an irradiated person, but not in the irradiated person, this is called the

genetic effect

46

a dose response curve indicating that any amount of radiation, no matter how small, has the potential to cause a biological response is called

nonthreshold

47

ALARA stand for

as low as reasonably achievable

48

five possible biological responses of an irradiated cell

o Nothing-the cell is unaffected by the exposure
o Cell is injured or damaged but repairs itself and functions at preexposure levels
o Cell dies, but is replaced through normal biological processes
o Cell is injured or damaged, repairs itself, but now functions at a reduced level
o Cell is injured or damaged and repairs itself incorrectly or abnormally, resulting in a biophysical change (tumor or malignancy)

49

according to the factors that determine radiation injury based on age, a _____________ year old is most radiosensitive

6 year old

50

sequence of events following radiation exposure

latent period
period of injury
recovery period

51

when a biological response is based on the probability of occurrence rather than the severity of the change it is called

a stochastic effect

52

what is considered a short term outcome following radiation exposure

acute radiation syndrome

53

full term, low birth weight is possibly associated with radiation exposure to

thyroid gland
hypothalamus
pituitary gland

54

During exposure of an intraoral dental radiograph, approximately how much smaller is the dose of radiation in the gonadal area than at the surface of the face?

0.0001

55

not considered critical for dental radiography

spinal cord

56

the potential risk of a full mouth dental x-ray examination inducing cancer to a patient has been estimated to be

2.5 per 1,000,000 examinations

57

term that best expresses comparisons between dental radiation exposure and natural background exposure

effective dose equivalent

58

the cornerstone of all healthcare professions

continuing education