RAD Protection & Radiobiology

RT 244 SELF STUDY UNIT = RAD Protection & Radiobiology

126 QUESTIONS

1)The focal spot-to-table distance, in mobile fluoroscopy, must be

(A) a minimum of 15 inches

(B) a maximum of 15 inches

(D) a maximum of 12 inches

2)The effects of radiation to biologic material are dependent on several factors. If a

Quantity of radiation is delivered to a body over a long period of time, the effect

(A) will be greater than if it were delivered all at one time

(B) will be less than if it were delivered all at one time

(D) is solely dependent on the radiation quality

3)LET is

a method of expressing radiation quality
a measure of the rate at which radiation energy is transferred to soft tissue
absorption of polyenergetic radiation

(A) 1 only

(B) 1 and 2 only

(D) 1,2, and 3

4)It is essential to question a female patient of childbearing age regarding

the date of her last menstrual period
the possibility of her being pregnant
the number of children she presently has

(A) 1 only

(B) 1 and 2 only

(D) 2 and 3 only

5)In 1906 Bergonie and Tribondeau established their law, which states that cells are

more radiosensitive if they

are young
are stem cells
have a low proliferation rate

(A)1 only

(B)1 and 2 only

(D)1,2, and 3

6)What is the effect on relative biologic effectiveness (RBE) as LET increases

(A) as LET increases, RBE increases

(B) as LET increases, RBE decreases

(D) LET has no effect on RBE

7)The NCRP recommends an annual effective occupational dose equivalent limit of

(A) 2.5 rem (25mSv)

(B) 5 rem (50 mSv)

(D) 20 rem (200 mSv)

8)Which of the following groups of exposure factors will deliver the LEAST amount of exposure to the patient?

(A) 400 mA, 0.2 sec, 100 kVp

(B) 600 mA, 0.33 sec, 90 kVp

(D) 800 mA, 1.0 sec, 70 kVp

9)Sources of natural background radiation exposure include

the food we eat
air travel
medical and dental x-rays

(A)1 only

(B)1 and 2 only

(D)1,2, and 3

10)Each time an x-ray beam scatters, its intensity at 1 meter from the scattering object is what fraction of its original intensity?

(A)1/10

(B) 1/100

(D) 1/1000

11)Types of gonadal shielding include which of the following?

flat contact
shaped (contour) contact
shadow

(A)1 only

(B)1 and 2 only

(D)1,2, and 3

12)A thermoluminescent dosimetry system would use which of the following crystals?

(A) silver bromide

(B) sodium sulfite

(D) ferrous sulfate

13)Sources of secondary radiation include

background radiation
leakage radiation
scattered radiation

(A) 1 only

(B) 1 and 2 only

(D) 1,2, and 3

14)Filters used in radiographic x-ray tubes are generally composed of

(A) aluminum

(B) copper

(D) lead

15)The photoelectric process is an interaction between an x-ray photon and

(A) an inner-shell electron

(B) an outer-shell electron

(D) another photon

16)The reduction in radiation intensity as it passes through materials termed

(A) absorption

(B) scattering

(D) divergence

17)In radiation protection, the product of absorbed dose and the correct modifying

factor (rad x QF) is used to determine

(A) roentgen (C/kg)

(B) rem (Sv)

(D) radiation quality

18)According to National Council on radiation Protection and Measurements (NCRP) regulations, leakage radiation from the x-ray tube must NOT exceed

(A) 10 mR/hr

(B) 100 mR/hr

(D) 100 mR/min

19)Which of the following statements regarding the human gonadal cells is (are) true?

The female oogonia reproduce only during fetal life.
The male spermatogonia reproduce continuously
Both male and female stem cells reproduce only during fetal life

(A) 1 only

(B) 2 only

(D) 3 only

20)To be in compliance with radiation safety standards, the fluoroscopy switch must

(A) sound during fluoro-on time

(B) be on a 6-foot-long cord

(D) be the dead-man type

21)Primary radiation barriers must be at LEAST how high?

(A) 5 feet

(B) 6 feet

(D) 8 feet

22)The annual dose limit for occupationally exposed individuals is valid for

(A) alpha, beta, and x-radiations

(B) x and gamma radiations only

(D) all ionizing radiations

23)The interaction between x-ray photons and matter pictured in Figure 3-1 is

associated with

high-energy x-ray photons
ionization
characteristic radiation

(A) 1 only

(B) 1 and 2 only

(D) 2 and 3 only

24)The likelihood of adverse radiation effects to any radiographer whose dose is

kept below the recommended guideline is

(A) very probable

(B) possible

(D) zero

25)The purpose of filters in a film badge is

(A) to eliminate harmful rays

(B) to measure radiation quality

(D) as a support for film contained within

26)The unit of absorbed dose is the

(A) roentgen (C/kg)

(B) rad (Gy)

(D) RBE

27)The Law of Bergonie and Tribondeau states that cells are more radiosensitive if they are

highly mitotic
undifferentiated
mature cells

(A) 1 only

(B) 1 and 2 only

(D) 1,2, and 3

28) Medical and dental radiation accounts for what percentage of the general public’s

exposure to man-made radiation?

(A) 10%

(B) 50%

(D) 90%

29)Skin response to radiation exposure, appearing as hair loss, is known as

(A) dry desquamation

(B) moist desquamation

(D) epilation

30) Biologic material is MOST sensitive to irradiation under which of the following

conditions?

(A) anoxic

(B) hypoxic

(D) deoxygenated

31) Which of the following terms refers to the period between conception and birth?

(A) gestation

(B) congenital

(D) in vitro

32)Which of the following have an effect on the amount and type of radiation-induced tissue damage?

quality of radiation
type of tissue being irradiated
fractionation

(A)1 only

(B) 1 and 2 only

(D) 1,2, and 3

33) The presence of ionizing radiation may be detected in which of the following

ways?

ionizing effect on air
physiologic effect on living tissue
fluorescent effect on certain crystal

(A)1 only

(B)1 and 2 only

(D)1,2, and 3

34)What unit of measure expresses the amount of energy deposited in tissue?

(A) roentgen (C/kg)

(B) rad (Gy)

(D) RBE

35)An undifferentiated cell is a

precursor cell
stem cell
mature cell

(A) 1 only

(B) 1 and 2 only

(D) 1,2, and 3

36)Which stage of mitosis is considered the MOST radiosensitive?

(A) prophase

(B) metaphase

(D) telophase

37)The dose-response curve that appears to be valid for genetic and some somatic

effect is the

linear
sigmoidal
nonthreshold

(A) 1 only

(B) 1 and 3 only

(D) 1,2, and 3

38)Which of the following illustrates the Inverse Square Law?

that distance is a most effective protection from radiation
that distance is a rather ineffective protection from radiation
as distance from the radiation source decreases, radiation decreases

(A)1 only

(B)1 and 2 only

(D)2 and 3 only

39)Which of the following disorders is MOST likely to result from irradiation of the

fetus in utero during the first trimester?

(A) leukemia

(B) sterility

(D) bone marrow syndrome

40)How much protection is provided from a 75 kVp x-ray beam when using a

0.25-mm lead equivalent apron?

(A)51%

(B)66%

(D)99%

41)Which of the following is a measure of dose to biologic tissue?

(A)roentgen (C/kg)

(B)rad (Gy)

(C)rem (Sv)

(D)RBE

42)Most radiation detectors operate on which of the following x-ray characteristics?

(A)luminescent effects

(B)ionization effects

(C)physiologic effects

(D)thermionic emission

43)What is the intensity of scattered radiation perpendicular to and 1 meter from the

patient, compared to the useful beam at the patient’s surface?

(A)0.01%

(B)0.1%

(D)10.0%

44)Which of the following are features of fluoroscopic equipment, designed especially to eliminate unnecessary radiation exposure to the patient and

or personnel ?

bucky slot cover
exposure switch/ foot pedal
cumulative timer

(A)1 only

(B)1 and 2 only

(D)1,2, and 3

45)The biologic effect to an individual is dependent on which of the following?

type of tissue interaction(s)
amount of interactions
biologic differences

(A)1 and 2 only

(B)1 and 3 only

(D)1,2, and 3

46)Protective devices such as lead aprons function to protect the user from

scattered radiation
the primary beam
remnant radiation

(A)1 only

(B)1 and 2 only

(D)1,2, and 3

47)If an individual receives 90 mR which standing 4 feet from a source of radiation

for 2 minutes, which of the options listed below will MOST effectively reduce his or her radiation exposure?

(A)standing 3 feet from the source for 2 minutes

(B)standing 2 feet from the source for 1 minute

(C)standing 5 feet from the source for 1 minute

(D)standing 6 feet from the source for 2 minutes

48)Which of the following tissues or organs is the MOST radiosensitive?

(A)rectum

(B)esophagus

(C)small bowel

(D)CNS

49)The dose of radiation that will cause a noticeable skin reaction is referred to as the

(A)LET

(B)SSD

(C)SED

(D)SID

50)The photoelectric effect is the interaction between x-ray photons and matter that

is largely responsible for patient dose. The photoelectric effect is likely to occur

under which of the following conditions?

with absorbers of high atomic number
with low-energy incident photons
with use of positive contrast media

(A)1 and 2 only

(B)1 and 3 only

(D)1,2, and 3

51) Diagnostic x-radiation may be correctly described as

(A) low energy , low linear energy transfer (LET)

(B) low energy, high LET

(D) high energy, high LET

52) Which of the following contributes MOST to occupational exposure?

(A) photoelectric effect

(B) compton scatter

(D) thompson scatter

53) Which of the following factors can affect the amount of nature of radiation damage to biologic tissue?

1. radiation quality

2. absorbed dose

3. size of irradiated area

(A) 1 only

(B) 2 only

( C) 1 and 2 only

(D) 1,2 and 3

54) Which of the following is (ARE) acceptable way(s) to monitor radiation exposure to those occupationally employed?

1. film badge

2. TLD

3. quarterly blood count

(A) 1 only

(B) 1 and 2 only

( C) 1 and 3 only

(D) 1, 2 and 3

55) The exposure rate to a body 3 feet from a source of radiation is 22 R/hr. What distance from the source would be necessary to decrease the exposure to 8 R/hr?

(A) 1 foot

(B) 2 feet

( C) 5 feet

(D) 8 feet

56) Biologic material irradiated under hypoxic conditions is:

(A) more sensitive than when irradiated under oxygenated conditions

(B) less sensitive than when irradiated under anoxic conditions

( C) less sensitive than when irradiated under oxygenated conditions

(D) unaffected by presence or absence of oxygen

57) Which of the following is (ARE) helpful in minimizing patient exposure?

1. accurate positioning

2. high kV, low mAs factors

3. rare earth screens

(A) 1 only

(B) 1 and 2 only

( C) 1 and 3 only

(D) 1, 2 and 3

58) Which of the following body parts is (ARE) included in whole-body dose?

1. gonads

2. lens

3. extremities

(A) 1 only

(B) 1 and 2 only

( C) 1 and 3 only

(D) 1, 2 and 3

59) If the exposure rate to a body standing 5 feet from a radiation source is 12 mR/ min, what will be the dose to that body at a distance of 12 feet from the source?

(A) 2 mR/min

(B) 5 mR/min

(D) 69 mR/min

60) Which of the following personal monitoring devices used in diagnostic radiography is considered to be the MOST sensitive and accurate?

(A) TLD

(B) film badge

(D) pocket dosimeter

61) Which of the following define the gonadal dose that, if received by every member of the population, would be expected to produce the same total genetic effect on that population as the actual doses received by each of the individuals?

(A) genetically significant dose

(B) somatically significant dose

(D) lethal dose

62) Cancer and genetic defects are examples of ______effects.

(A) stochastic

(B) Nonstochastic

(D) deterministic

63) Which of the following personal radiation monitors will provide an immediate reading?

(A) TLD

(B) film badge

(D) pocket dosimeter

64) Irradiation of water molecules within the body, and their resulting breakdown, is termed:

(A) epilation

(B) radiolysis

(D) re-population

65) Radiation that passes through the tube housing in directions other than that of the useful beam is termed:

(A) scattered radiation

(B) secondary radiation

(D) remnant radiation

66) Which of the following are considered especially radiosensitive tissues?

1. blood-forming organs

2. reproductive organs

3. lymphosis

(A) 1 only

(B) 1 and 2 only

(D) 1, 2 and 3

67) If the exposure rate at 2 feet from the fluoroscopic table is 200 mR/hr, what will be the exposure rate in 20 minutes at a distance of 5 feet from the table?

(A) 41 mR

(B) 32 mR

(D) 10 mR

68) What is the single MOST important scattering object in both radiography and fluoroscopy?

(A) x-ray table

(B) x-ray tube

(D) film

69) Lethal dose of ionizing radiation for humans is usually given as:

(A) LD 50/30

(B) LD 50/60

(D) LD 50/120

70) Which of the following are classified as HIGH-LET radiations?

1. alpha particles

2. gamma rays

3. X-rays

(A) 1 only

(B) 2 only

(D) 1, 2 and 3

71) At a 90-degree angle to the primary x-ray beam , at a distance of 1m (3.3 feet), the scattered radiation is what faction of the intensity of the primary beam?

(A) 1/10

(B) 1/100

(D) 1/10000

72) Acute radiation syndrome presents in four major stages. In what order do these stages occur?

(A) latent period, prodromal, manifest illness, recovery or death

(B) manifest illness, prodromal, latent period, recovery or death

(D) manifest illness, latent period, prodromal, recovery or death

Use the list that follows to answer questions 73-86. Items may be used more than once. Choose the one best answer for each question.

A. Photoelectric interaction

B. Compton’s scatter

C. Coherent scatter

D. Pair production

E. Primary radiation ; exit radiation

73) Occurs above 1.02 million electron volts

74) Also called incoherent scattering

75) Radiation coming from the anode; radiation exiting the patient

76) Photon-tissue interaction that never occurs in diagnostic radiography

77) Responsible for producing contrast on a radiograph

78) Produces scatter radiation that exits the patient and may fog the radiograph

79) Produces scatter energy as a result of vibration of orbital electrons

80) Radiation striking the patient ; image-forming radiation

81)Results in total absorption of incident photons

82) Only photon-tissue interaction that does not result in ionization

83) Only photon-tissue interaction that involves an incident photon and atomic nucleus

84) Photon-tissue interaction that primarily involves K-shell electrons

85) Photon- tissue interaction that primarily involves loosely bound outer-shell electrons

86) Results in the production of a photoelectron that is ejected from the atom

87) The annual dose limit to medical imaging personnel includes radiation from

1. medical x-rays

2. occupational exposure

3. background radiation

(A) 1 only

(B) 2 only

(D) 1, 2 and 3

88) In which type of monitoring device do photons release electrons by their interaction with air?

(A) film badge

(B) thermoluminescent dosimeter (TLD)

(C ) ion chamber

(D) scintillation detector

89) Which of the following is (ARE) possible long term somatic effects of radiation exposure?

1. nausea and vomiting

2. carcinogenesis

3. leukemia

(A) 1 only

(B) 1 and 2 only

(D) 1, 2 and 3

90) The skin response to radiation exposure which appears as reddening of the irradiated skin area, is known as

(A) dry desquamation

(B) moist desquamation

(D) epilation

91) Immature cells are referred to as:

1.undifferentiated

2. stem

3. genetic

(A) 1 only

(B) 1 and 2 only

(D) 1, 2 and 3

92) Radiographers use monitoring devices to record their monthly exposure to radiation. The type (s) of device (s) used would MOST likely be which of the following?

1. film badge

2. TLD

3. cutie pie

(A) 1 only

(B) 1 and 2 only

(D) 1, 2 and 3

93) Early symptoms of acute radiation syndrome include:

1. leukemia

2. nausea and vomiting

3. cataracts

(A) 1 and 2 only

(B) 2 only

(D) 2 and 3 only

94) If a radiographer stands 6m away from an x-ray tube and receives an exposure rate of 4 mR per hour, what will the exposure rate be if the same radiographer moves to stand at a position located 12 m from the x-ray tube?

(A) 1 mR per hour

(B) 2 mR per hour

(D) 4 mR per hour

95) The unit of dose equivalency is the rem ; it is calculated using the following equation: rads x quality factor ; the SI unit of absorbed dose equivalent is the sievert

(A) This statement is correct, complete, and accurate as written; no choices below correct or complete it

(B) The unit of dose equivalency is the rem; it is calculated using the following equations: rads x quality factor : the SI unit of absorbed dose equivalent is the sievert; the rem takes into account different biologic effects caused by various sources of radiation; the rem is the unit reported on film badge reports

(C) The unit of dose equivalency is the rem; it is calculated using the following equation: rads x quality factor ; the SI unit of absorbed dose equivalent is the sievert; the rem takes into account different biologic effects caused by various sources of radiation

(D) The unit of dose equivalency is the rem; it is calculated using the following equation: rads x quality factor; the SI unit of absorbed dose equivalent is the sievert; the rem is the unit reported on film badge reports

For each of the following questions, choose the single best answer

96) The amount of energy deposited by radiation per unit length of tissue being traversed is:

(A) LET, which determines the use of a QF when calculating the absorbed dose equivalent

(B) linear energy transfer

(D) LET, which is expressed as QF when calculating absorbed dose

97) The agency that publishes radiation protection standards based on scientific research:

(A) Nuclear Regulatory Commission (NRC)

(B) International Commission on Radiation Protection (ICRP)

(D) bureau of Radiological Health (BRH)

98) The agency that enforces radiation protection standards at the federal level is the:

(A) Nuclear Regulatory Commission (NRC)

(B) International Commission on Radiation Protection (ICRP)

(D) bureau of Radiological Health (BRH)

99) Effective absorbed dose equivalent limit is defined as the upper boundary dose that:

(A) Can be absorded annually with a negligible risk of somatic or genetic damage to the individual

(B) Can be absorded, either in a single exposure or annually, with no risk of damage to the individual

(C) Can be absorded, either in a single exposure or annually, with no risk of somatic or genetic damage to the individual

(D) Can be absorded, either in a single exposure or annually, with a negligible risk of somatic or genetic damage to the individual