Radiological Units, Quantities, and Terminology

Question 1

Exposure

Answer 1

Energy deposited by ionizing radiation

Question 2

Roentgen

Answer 2

Amount of X-ray or gamma radiation less than or equal to 3 MeV that will produce in air 2.58 c 10^-4 coulombs of charge per Kilo of air.

Question 3

Absorbed Dose (D)

Answer 3

Energy imparted by ionizing radiation per unit mass of irradiated material.
1. Unit of absorbed dose is the Gray(Gy) or rad
2. rad- equal to the absorption of 100 ergs per gram
3. Ergs- amount of energy required to lift a mass of 1/980
4. Gray = 1J/kg = 100 rad

Question 4

Quality Factor (Q)

Answer 4

Factor which is multiplied by absorbed dose to obtain a quantity which equates to a common scale of any ionizing radiation that an individual is exposed.

Question 5

Quality Factor (Q) types

Answer 5

Photons:1
Beta + beta - : 1
Thermal Neutrons: 2
Fast Neutron : 10
Protons: 10
Alpha Particle: 20

Question 6

Dose Equivalent (Ht)

Answer 6

Product of absorbed dose and quality factor. Purpose to have a single unit regardless of type radiation

Question 7

Rem

Answer 7

Unit of dose equivalent

Question 8

Rem ( Naval Nuclear Propulsion Program)

Answer 8

The amount of any type of radiation that will cause biological damage equivalent to 1 rad of gamma radiation

Question 9

Sievert (Sv)

Answer 9

One Sv = 100 rem

Question 10

Man-rem (person rem)

Answer 10

Total radiation dose received by all of the individuals in a specific group over a specified period of time or during a specific work event

Question 11

Effective Dose equivalent (He)

Answer 11

Sum of the products of the weighting factors applicable to each of the body organs or tissues that are irradiated and the dose equivalent to these organs or tissues

Question 12

Organ/ Tissue weighting Factor

Answer 12

Gonads 0.25
Breast 0.15
RB marrow 0.12
Lung. 0.12
Thyroid. 0.03
Bone Surface. 0.03
Remainder. 0.30
Whole Body. 1.00

Remainder is GI system

Question 13

Deep Dose Equivalent

Answer 13

External Exposure to the whole body at a tissue depth of 1cm

Question 14

Shallow Dose Equivalent

Answer 14

External exposure to the skin or extremity at a tissue depth 0.007 cm

Question 15

Eye dose equivalent

Answer 15

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

Question 16

Committed Dose Equivalent

Answer 16

Dose Equivalent to an organ or tissue that will be received from an intake of radioactive material by an individual during a 50 year period following intake

Question 17

Committed effective dose equivalent

Answer 17

Sum of products of the weighting factors applicable to each of the body organs or tissues that are irradiated and the committed dose equivalent to these organs or tissues

Question 18

Total Effective dose equivalent (TEDE)

Answer 18

Sum of deep dose equivalent and the committed effective dose equivalent

TEDE= DDE + CEDE

Question 19

Annual limit on intake (ALI)

Answer 19

Smaller amount of radioactive material taken into the body by an adult worker by inhalation or ingestion in a year that would result in a committed effective dose equivalent of 5 rem committed or committed dose equivalent of 50 rem

Question 20

Derived Air Concentration (DAC)

Answer 20

Concentration of a given radionuclide in air which, if breathed for a working year under conditions of light work results in an intake of Annual limit on intake (ALI)

Question 21

ALARA

Answer 21

As low as reasonably Achievable
radiological protection philosophy making every reasonable effort to maintain exposure to ionizing radiation below dose limits.