Radiology Chapter 5&6

Question 1

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

Answer 1

Acute radiation syndrome (ARS)

Question 2

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

Answer 2

ALARA

Question 3

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

Answer 3

cumulative effect

Question 4

when the severity of the change is dependent on the dose

Answer 4

deterministic effect

Question 5

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

Answer 5

direct theory

Question 6

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

Answer 6

dose response curve

Question 7

cells contained within the testes and ovaries, containing the genes

Answer 7

genetic cells

Question 8

radiation effect that is passed on to future generations

Answer 8

genetic effect

Question 9

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

Answer 9

genetic mutation

Question 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

Answer 10

indirect theory

Question 11

formation of ion pairs

Answer 11

ionization

Question 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

Answer 12

irradiation

Question 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

Answer 13

irreparable injury

Question 14

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

Answer 14

latent period

Question 15

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

Answer 15

law of B and T

Question 16

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

Answer 16

lethal dose

Question 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

Answer 17

nonthreshold dose response curve

Question 18

radiation-induced changes that follow the latent period

Answer 18

period of injury

Question 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

Answer 19

radiolysis of water

Question 20

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

Answer 20

radioresistant

Question 21

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

Answer 21

radiosensitive

Question 22

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

Answer 22

recovery period

Question 23

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

Answer 23

risk

Question 24

any body cells except the reproductive cells

Answer 24

somatic cells

Question 25

when radiation affects all body cells except the reproductive cells

Answer 25

somatic effect

Question 26

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

Answer 26

stochastic effect

Question 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

Answer 27

threshold dose response curve

Question 28

Inventors of Law of B and T

Answer 28

Bergonie and Tribondeau

Question 29

radiosensitive cells from high sensitivity to low sensitivity

Answer 29

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

Question 30

somatic effect occurs when

Answer 30

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

Question 31

genetic effect describes

Answer 31

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

Question 32

factors that determine radiation injuries

Answer 32

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

Question 33

critical tissues for dental radiography in head and neck region

Answer 33

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

Question 34

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

Answer 34

no adverse biological effect

Question 35

x-rays ionize water, resulting in

Answer 35

formation of free radicals, which recombine to form toxins

Question 36

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

Answer 36

almost 75% during the first 24 hours

Question 37

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

Answer 37

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

Question 38

genetic cells cannot

Answer 38

repair themselves

Question 39

the primary cause of biological damage from radiation is

Answer 39

ionization

Question 40

direct injury from radiation occurs when the x-ray photons

Answer 40

strike critical cell molecules

Question 41

indirect injury from radiation occurs when the x-ray photons

Answer 41

ionize water and form toxins

Question 42

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

Answer 42

radiosensitive

Question 43

what cells are most radiosensitive?

Answer 43

white blood cells

Question 44

what cells are most radioresistant?

Answer 44

muscle cells

Question 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

Answer 45

genetic effect

Question 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

Answer 46

nonthreshold

Question 47

ALARA stand for

Answer 47

as low as reasonably achievable

Question 48

five possible biological responses of an irradiated cell

Answer 48

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)

Question 49

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

Answer 49

6 year old

Question 50

sequence of events following radiation exposure

Answer 50

latent period period of injury recovery period

Question 51

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

Answer 51

a stochastic effect

Question 52

what is considered a short term outcome following radiation exposure

Answer 52

acute radiation syndrome

Question 53

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

Answer 53

thyroid gland hypothalamus pituitary gland

Question 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?

Answer 54

0.0001

Question 55

not considered critical for dental radiography

Answer 55

spinal cord

Question 56

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

Answer 56

2.5 per 1,000,000 examinations

Question 57

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

Answer 57

effective dose equivalent

Question 58

the cornerstone of all healthcare professions

Answer 58

continuing education