Unit 1.3

Question 1

Define Exposure; what units do we use for exposure?

Answer 1

Receipt of ionizing radiation by proximity to external radiation or by intake of material. We use Roentgen.

Question 2

Define Absorbed Dose; what units do we use for Absorbed dose?

Answer 2

The energy imparted by ionizing radiation per unit mass of irradiated material. Units are Rad (or Gray).

Question 3

What is the Linear Energy Transfer?

Answer 3

Rate of energy absorbed by a medium along the track of an ionizing particle; aka the amount of energy given off by a particle as it travels.

Question 4

What is a Quality Factor?

Answer 4

It is the factor that is multiplied by the absorbed dose to obtain a dose equivalent for any type of radiation. Said differently, it is the correction factor for the differing “power” of each type of radiation.

Question 5

What is the quality factor for a photon?

Answer 5

1

Question 6

What is the quality factor for a alpha particle?

Answer 6

20

Question 7

What is the quality factor for a neutron of unknown energy?

Answer 7

10

Question 8

What is the quality factor for a proton?

Answer 8

10

Question 9

What is the quality factor for multiple charged particles or fission fragments?

Answer 9

20

Question 10

What is the quality factor for electrons?

Answer 10

1

Question 11

What is the quality factor for a beta particle (positive or negative)?

Answer 11

1

Question 12

What is the quality factor for a thermal neutron?

Answer 12

2

Question 13

What is a dose equivalent, and what is its unit?

Answer 13

The equivalent amount of radiation, regardless of type of radiation, used to help describe the effect on man. It is measured in Rem or Sievert.

Question 14

Explain what is an Effective Dose Equivalent [H(e)]?

Answer 14

The sum of the doses to each individual body part/tissue that are irradiated after correction for tissue weighting factor.

Question 15

Explain what is a Tissue Weighting Factor?

Answer 15

The proportion of the risk of stochastic effects resulting from irradiation of that organ or tissue to the total risk of the effects when the whole body is irradiated uniformly.

Question 16

Identify the organs with the highest tissue weighting factors.

Answer 16

Gonads (25%)
Breast (15%)
Red Bone Marrow (12%)
Lung (12%)

Question 17

Define Deep Dose Equivalent [H(d)]

Answer 17

External exposure to the whole body at a depth of 1cm (not including extremities).

Question 18

Define Shallow Dose Equivalent [H(s)]s.

Answer 18

Esternal exposure to the skin or extremity at a depth of 0.007cm.

Question 19

Define Eye Dose Equivalent

Answer 19

External exposure to the lens of the eye at a depth of 0.3cm

Question 20

Define Committed Dose Equivalent [H(t,50)]

Answer 20

The dose equivalent to an organ or tissue that will be received from the intake of a radioactive material by an individual during the 50-year period following intake.

Question 21

Define Committed Effective Dose Equivalent [H(e,50) or CEDE].

Answer 21

The sum of the committed dose equivalent of all of the tissues in the body after correction for each tissue’s weighting factor.

Question 22

Define Total Effective Dose Equivalent (TEDE)

Answer 22

The sum of the deep dose equivalent and the committed effective dose equivalent. AKA all of the radiation given to a person.

Question 23

What is the annual limit on Intake for TEDE?

Answer 23

Federally it is 5 Rem/yr or 3 Rem/qtr. Also set to be 50 rem to one individual organ or tissue.

Question 24

What is the derived Air concentration (DAC)?

Answer 24

The concentration of a given radionuclide in air which, if breathed for a year under conditions of light work results in one ALI.
One work year = 40 hrs per week x 50 weeks (2000 hrs).

Question 25

Describe the ALARA principle.

Answer 25

As Low as Reasonably achievable; using economic and social factors to minimize ionizing radiation as far below dose limits as is practical.

Question 26

Define Rem; note that there are two definitions.

Answer 26

Rem P 5055: Dose Equivalent unit equal to dose absorbed in rad multiplied by quality factor.
Rem NNPP: Amount of radiation that will do equivalent damage as 1 Rad of gamma radiation.