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

Deterministic effects have a threshold dose; below it, no effect is observed, but above it, effect severity increases with dose as more cells are killed.

Question 2

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

Accepted Answer

1 to 2 Gy

Answer

ARS typically begins to manifest clinically after whole-body doses of approximately 1–2 Gy, with the hematopoietic syndrome being the first to appear.

Question 3

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

Accepted Answer

Bone marrow and blood-forming cells

Answer

The hematopoietic syndrome is caused by destruction of bone marrow stem cells, leading to decreased production of red blood cells, white blood cells, and platelets.

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

Bergonié and Tribondeau established that cells are more radiosensitive when they are undifferentiated (immature) and have a high mitotic rate.

Question 5

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

Accepted Answer

G2/M (late gap and mitosis)

Answer

Cells in G2 and M phase are most radiosensitive because DNA repair mechanisms are suppressed during mitosis and damage cannot be repaired before division.

Radiation Health and Safety Test Practice Test

Radiation Health and Safety Test Practice Test

Radiation Health and Safety Test Radiation Biology & Health Effects 2