Radiation Health and Safety Test Radiation Biology & Health Effects 2

Question 1

Deterministic (tissue) radiation effects are characterized by which dose-response relationship?

Accepted Answer

A threshold below which effects do not occur, and severity increases above that threshold

Answer

Linear no-threshold (LNT) with no minimum dose

Answer

A hormetic response where low doses are beneficial

Answer

A random probability of occurrence at any dose level

Question 2

Acute radiation syndrome (ARS) occurs after whole-body exposure generally above which dose range?

Accepted Answer

1 to 2 Gy

Answer

0.1 to 0.5 Gy

Answer

5 to 10 Gy

Answer

Greater than 20 Gy

Question 3

The hematopoietic syndrome of ARS primarily results from damage to which organ system?

Accepted Answer

Bone marrow and blood-forming cells

Answer

Gastrointestinal tract lining

Answer

Central nervous system

Answer

Skin and mucous membranes

Question 4

According to the Law of Bergonié and Tribondeau, cells are most sensitive to radiation when they are:

Accepted Answer

Undifferentiated and rapidly dividing

Answer

Highly differentiated and non-dividing

Answer

Large and metabolically inactive

Answer

In the G1 phase only

Question 5

Which phase of the cell cycle is generally considered the most radiosensitive?

Accepted Answer

G2/M (late gap and mitosis)

Answer

G1 (post-mitotic gap)

Answer

S phase (DNA synthesis)

Answer

G0 (resting phase)

Question 6

The relative biological effectiveness (RBE) compares the biological damage of a test radiation to that of:

Accepted Answer

250 kVp X-rays as the reference radiation

Answer

Alpha particles at 5 MeV

Answer

Thermal neutrons at 0.025 eV

Answer

Co-60 gamma rays at 1.25 MeV

Question 7

Radiation-induced cataracts are classified as which type of radiation effect?

Accepted Answer

Deterministic with a threshold dose

Answer

Stochastic with no threshold

Answer

Hereditary genetic effect

Answer

Teratogenic effect only in utero