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Nuclear Medicine > Radiation Safety > Flashcards

Radiation Safety Flashcards

1
Q

According to the NRCP 160, what are the approximate annual doses to the U.S. population from natural background and man-made sources of ionizing radiation?

A

310 mrem - Natural Background
300 mrem - Man-made Sources

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2
Q

A 100 mCi point source of I-131 is located 5.0 cm from you. What is the exposure rate at your location?

(UGamma (I-131) = 0.22 R-m^2 / Ci-h)

A

8.8 R/h

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3
Q

According to the NRC, the annual radiation exposure to members of the general public must be limited to no more than:

A

100 mrem

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4
Q

Optimum beta particle shielding consists of:

A

Low atomic number material followed by high atomic number material

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5
Q

If the distance between a radiation point source and a survey meter is doubled, the measured exposure rate is reduced to:

A

1/4 of the original exposure rate

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6
Q

If the half-value layer (HVL) for I-131 in lead is 0.3 cm, what is the minimum thickness of lead that is required to reduce the exposure rate of a I-131 source from 12 mR/hr to less than 2 mR/hr?

A

> 0.9 cm

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7
Q

A Becquerel is equivalent to:

A

1 Disintegration per second

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8
Q

The dose rate during preparation of a radiopharmaceutical is 1.66 mrem/hr. With this rate reduced by 2 HVLs, how many hours would it take a worker to accumulate 10 mrem?

A

24 h

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9
Q

Which quantity indicates the amount of radioactive substance present in a sample or source?

A

Activity

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10
Q

If the radiation intensity of a point source at 0.5 m measures 35 mR/h, at what distance will the intensity be halved?

A

0.7 m

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11
Q

The average energy required to create an ion pair in air is:

A

34 eV

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12
Q

The gray (Gy) is a unit representing which dosimetric quantity?

A

Absorbed Dose

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13
Q

The variable indicating the type of radiation used in the calculation of the equivalent dose is called the:

A

Radiation Weighting Factor

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14
Q

Which of the dosimetric quantity accounts for partial body exposure (ie., it accounts for total dose from individual organs/tissues)?

A

Effective Dose

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15
Q

Which of the following quantities is define as the energy absorbed per unit mass?

A

Absorbed Dose

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16
Q

A Sievert is defined to be:

A

1 J/kg

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17
Q

The rad is defined as the deposition of: (___ erg/g ____)

A

100 erg/g in any material

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18
Q

The dose rate outside a shield wall is found to be 0,5 mrad/h from Ra-223 (an alpha emitter). What is the equivalent dose rate of the radiation field?

A

10 mrem/h

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19
Q

A NMT measures a Tc-99m Mag-3 Dose prior to injecting a patient. The standard dose for an adult renogram procedure is 5.0 mCi. What is the highest amount of activity that can be injected, per NRC regulation?

A

6.0 mCi (NRC is +/- 20% Dose)

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20
Q

The critical organ is defined as:

A

The organ that is most radiosensitive.

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21
Q

Provide the Annual Occupational radiation Dose Limits in rem for the following:
a) Whole-Body
b) Lens of the Eye
c) Any Organ/Tissue
d) Extremity or Skin

A

a) 5 rem
b) 15 rem
c) 50 rem
d) 50 rem

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22
Q

What are the three basic principles of radiation protection?

A

Time, Distance, and Shielding.

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23
Q

Define the units:

Activity

A

Curie (Ci) / Becquerel (Bq)

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24
Q

Define the units:

Exposure

A

Roentgen (R) / Coulombs per Kilogram (C/kg)

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25
Q

Define the units:

Absorbed Dose

A

Radiation Absorbed Dose (rad) / Gray (Gy)

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26
Q

Define the units:

Equivalent Dose

A

Radiation Equivalent Man (rem) / Sievert (Sv)

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27
Q

Define the units:

Effective Dose

A

Radiation Equivalent Man (rem) / Sievert (Sv)

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28
Q

What Electron Volt energy level is considered “Non-Ionizing”

A

< 13.6 eV

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29
Q

What Electron Volt energy level is considered “Ionizing”

A

> 13.6 eV

30
Q

Annual dose for occupational workers:

A

5,000 mrem/y

31
Q

Annual dose for members of the public:

A

100 mrem/y

32
Q

What is the NRC?

A

Nuclear Regulatory Commission

33
Q

What is the DoT?

A

Department of Transportation

34
Q

What is the FDA?

A

Food & Drug Administration

35
Q

What is the EPA?

A

Environmental Protection Agency

36
Q

What is the RSC?

A

Radiation Safety Committee

37
Q

What is required in order for a facility to produce or use radionuclides, radiopharmaceuticals, or radiation equipment?

A

A license from the NRC

38
Q

Human tissue consists of which two cells types?

A

Germ cells: Responsible for reproduction.
Somatic cells: responsible for maintenance of functions in the body.

39
Q

Minimum energy required to produce an Ion pair

A

34 eV

40
Q

LET = ?

(Formula)

A

SI (Specific Interaction) * 34 eV

41
Q

Activity/Dose Rate Formula

A

A1 / X1 = A2 / X2

42
Q

Point Source Dose Rate Formula

A

(Point Source) = ((Gamma Constant) * A) / d^2

43
Q

ALARA = ?

A

As Low As Reasonably Achievable

44
Q

Inverse Square Law Formula

A

I1 * d1^2 = I2 * d2^2

45
Q

3 Principles of Radiation Safety

A

Time, Distance, Shielding

46
Q

Intensity Formula

A

I = I1 * e^(-u * x)

I = Final Intensity
I1 = Initial Intensity
u = Linear Attenuation
x = Thickness

47
Q

What does a cell consist of?

A

A nucleus surrounded by cytoplasm.

48
Q

Half Value Layer Formula

A

I = I1 * e^(-(ln2/HVL) * x)

I = Final Intensity
I1 = Initial Intensity
u = (ln2/HVL)
x = Thickness

49
Q

Tenth Value Layer Formula

A

I = I1 * e^(-(ln10/TVL) * x)

I = Final Intensity
I1 = Initial Intensity
u = (ln10/TVL)
x = Thickness

50
Q

The denser the material is for radiation protection:

A

The less material that is required.

51
Q

The nucleus consists of?

A

DNA & metabolic activities carried out by nucleus.

52
Q

The primary mechanism of cellular damage is the breakdown of the strands of DNA known as a:

A

Mutation

53
Q

The number of mutations increases with ?

A

increasing radiation exposure

54
Q

Low exposure = ?

A
  • Single strand breaks
  • DNA repairs over time
55
Q

High exposure = ?

A
  • Double strand breaks
  • Decreased chance for DNA repair
56
Q

Direct

A
  • Ionizing particle directly interacts w/ an atom
  • Damages DNA directly
57
Q

Indirect

A
  • Radiation interacts w/ water near the DNA
  • Subsequent attack on the DNA molecules.
58
Q

Free Radicals

A
  • Highly reactive compounds
  • containing an unpaired electron
  • chemically toxic to molecules
59
Q

What is the Law of Bergonie & Tribondeau ?

A

biological damage resulting from radiation exposure, radiosensitivity greater in cells with:

  1. relatively undifferentiated ( primitive ).
  2. rapidly dividing at the tome of irradiation.
  3. dividing for extended periods of time.
60
Q

Which factors affect the radiosensitivity of cells?

A
  1. Dose & Dose Rate
  2. Linear Energy Transfer
  3. Radiosensitizeer & Radioprotector
  4. Cell Cycle
61
Q

Dose Rate = ?

A

Dose / time

62
Q

Low dose & dose rate = ?

A

Single strand breaks, likely to be 100% repaired

63
Q

High dose & dose rate =?

A

Double strand breaks, not likely to be repaired

64
Q

LET ( linear energy transfer )

A

Energy given up by radiation when it interacts w/ matter

65
Q

High LET = ?

A

Radiation gives up its energy over a short distance. (Alpha particles)

66
Q

Low LET =?

A

Radiation that gives up its energy over long distances. (Beta particles & Gamma)

67
Q

Radiosensitizers = ?

A

increased damage to DNA. (ex. Oxygen)

68
Q

Radioprotectors = ?

A

protects the cell from damage. (ex. Cysteine, cysteamine)

69
Q

What is the Hormesis theory?

A
  • low doses of ionizing radiation
  • mechanism that protects against diseases not active in the absence of ionizing radiation.
70
Q

What is the Linear No Threshold (LNT) theory?

A
  • an increased risk for developing cancer at lowest radiation exposures, (straight line graph)
71
Q

What is the Threshold Response theory?

A
  • a threshold below which there is no increased risk for developing cancer.

Nuclear Medicine (6 decks)

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