Radiation Safety

Question 1

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?

Answer 1

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

Question 2

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)

Answer 2

8.8 R/h

Question 3

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

Answer 3

100 mrem

Question 4

Optimum beta particle shielding consists of:

Answer 4

Low atomic number material followed by high atomic number material

Question 5

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

Answer 5

1/4 of the original exposure rate

Question 6

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?

Answer 6

> 0.9 cm

Question 7

A Becquerel is equivalent to:

Answer 7

1 Disintegration per second

Question 8

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?

Answer 8

24 h

Question 9

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

Answer 9

Activity

Question 10

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

Answer 10

0.7 m

Question 11

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

Answer 11

34 eV

Question 12

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

Answer 12

Absorbed Dose

Question 13

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

Answer 13

Radiation Weighting Factor

Question 14

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

Answer 14

Effective Dose

Question 15

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

Answer 15

Absorbed Dose

Question 16

A Sievert is defined to be:

Answer 16

1 J/kg

Question 17

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

Answer 17

100 erg/g in any material

Question 18

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?

Answer 18

10 mrem/h

Question 19

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?

Answer 19

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

Question 20

The critical organ is defined as:

Answer 20

The organ that is most radiosensitive.

Question 21

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

Answer 21

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

Question 22

What are the three basic principles of radiation protection?

Answer 22

Time, Distance, and Shielding.

Question 23

Define the units:

Activity

Answer 23

Curie (Ci) / Becquerel (Bq)

Question 24

Define the units:

Exposure

Answer 24

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

Question 25

Define the units: Absorbed Dose

Answer 25

Radiation Absorbed Dose (rad) / Gray (Gy)

Question 26

Define the units: Equivalent Dose

Answer 26

Radiation Equivalent Man (rem) / Sievert (Sv)

Question 27

Define the units: Effective Dose

Answer 27

Radiation Equivalent Man (rem) / Sievert (Sv)

Question 28

What Electron Volt energy level is considered "Non-Ionizing"

Answer 28

< 13.6 eV

Question 29

What Electron Volt energy level is considered "Ionizing"

Answer 29

> 13.6 eV

Question 30

Annual dose for occupational workers:

Answer 30

5,000 mrem/y

Question 31

Annual dose for members of the public:

Answer 31

100 mrem/y

Question 32

What is the NRC?

Answer 32

Nuclear Regulatory Commission

Question 33

What is the DoT?

Answer 33

Department of Transportation

Question 34

What is the FDA?

Answer 34

Food & Drug Administration

Question 35

What is the EPA?

Answer 35

Environmental Protection Agency

Question 36

What is the RSC?

Answer 36

Radiation Safety Committee

Question 37

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

Answer 37

A license from the NRC

Question 38

Human tissue consists of which two cells types?

Answer 38

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

Question 39

Minimum energy required to produce an Ion pair

Answer 39

34 eV

Question 40

LET = ? (Formula)

Answer 40

SI (Specific Interaction) * 34 eV

Question 41

Activity/Dose Rate Formula

Answer 41

A1 / X1 = A2 / X2

Question 42

Point Source Dose Rate Formula

Answer 42

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

Question 43

ALARA = ?

Answer 43

As Low As Reasonably Achievable

Question 44

Inverse Square Law Formula

Answer 44

I1 * d1^2 = I2 * d2^2

Question 45

3 Principles of Radiation Safety

Answer 45

Time, Distance, Shielding

Question 46

Intensity Formula

Answer 46

I = I1 * e^(-u * x) I = Final Intensity I1 = Initial Intensity u = Linear Attenuation x = Thickness

Question 47

What does a cell consist of?

Answer 47

A nucleus surrounded by cytoplasm.

Question 48

Half Value Layer Formula

Answer 48

I = I1 * e^(-(ln2/HVL) * x) I = Final Intensity I1 = Initial Intensity u = (ln2/HVL) x = Thickness

Question 49

Tenth Value Layer Formula

Answer 49

I = I1 * e^(-(ln10/TVL) * x) I = Final Intensity I1 = Initial Intensity u = (ln10/TVL) x = Thickness

Question 50

The denser the material is for radiation protection:

Answer 50

The less material that is required.

Question 51

The nucleus consists of?

Answer 51

DNA & metabolic activities carried out by nucleus.

Question 52

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

Answer 52

Mutation

Question 53

The number of mutations increases with ?

Answer 53

increasing radiation exposure

Question 54

Low exposure = ?

Answer 54

- Single strand breaks - DNA repairs over time

Question 55

High exposure = ?

Answer 55

- Double strand breaks - Decreased chance for DNA repair

Question 56

Direct

Answer 56

- Ionizing particle directly interacts w/ an atom - Damages DNA directly

Question 57

Indirect

Answer 57

- Radiation interacts w/ water near the DNA - Subsequent attack on the DNA molecules.

Question 58

Free Radicals

Answer 58

- Highly reactive compounds - containing an unpaired electron - chemically toxic to molecules

Question 59

What is the Law of Bergonie & Tribondeau ?

Answer 59

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.

Question 60

Which factors affect the radiosensitivity of cells?

Answer 60

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

Question 61

Dose Rate = ?

Answer 61

Dose / time

Question 62

Low dose & dose rate = ?

Answer 62

Single strand breaks, likely to be 100% repaired

Question 63

High dose & dose rate =?

Answer 63

Double strand breaks, not likely to be repaired

Question 64

LET ( linear energy transfer )

Answer 64

Energy given up by radiation when it interacts w/ matter

Question 65

High LET = ?

Answer 65

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

Question 66

Low LET =?

Answer 66

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

Question 67

Radiosensitizers = ?

Answer 67

increased damage to DNA. (ex. Oxygen)

Question 68

Radioprotectors = ?

Answer 68

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

Question 69

What is the Hormesis theory?

Answer 69

- low doses of ionizing radiation - mechanism that protects against diseases not active in the absence of ionizing radiation.

Question 70

What is the Linear No Threshold (LNT) theory?

Answer 70

- an increased risk for developing cancer at lowest radiation exposures, (straight line graph)

Question 71

What is the Threshold Response theory?

Answer 71

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