Unit 1.5

Question 1

State the 4 basic methods of controlling internal radiation exposure.

Answer 1

Avoiding Inhalation
Avoiding Ingestion
Avoiding Absorption
Wound Decontamination

Question 2

State the 3 basic methods of controlling external radiation exposure.

Answer 2

Time, Distance, Shielding.
Remember that the dose received is inversely proportional to the square of the distance from a point source. Shielding can be installed or temporary.

Question 3

Read through examples of medical, nuclear, and radiographic applications of Time, Distance, Shielding applications.

Answer 3

practice, use tongs, use shielding.

Question 4

Define Half Value Layer

Answer 4

The thickness of a material required to block half of the intensity of a beam of gamma radiation.

Question 5

Define tenth-value layer.

Answer 5

The thickness of material required to reduce the intensity of a beam of gamma radiation to one tenth of its original value.

Question 6

What are the TVLs for Co-60 for steel, lead, and water/Oil?

Answer 6

Lead = 2”
Steel = 4”
H20, polyethylene, Oil = 24” (2 ft)

Question 7

What is the TVL for fast neutrons in Water, Polyethylene, or oil?

Answer 7

10”

Question 8

What is exposure?

Answer 8

It is the product of Intensity and Time, measured in Roentgen.