Radiation Biology & Health Effects Flashcards
7 cards from real Radiation Health and Safety Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Radiation Biology & Health Effects flashcards as text
Deterministic (tissue) radiation effects are characterized by which dose-response relationship?
Answer: A threshold below which effects do not occur, and severity increases above that threshold
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.
Acute radiation syndrome (ARS) occurs after whole-body exposure generally above which dose range?
Answer: 1 to 2 Gy
ARS typically begins to manifest clinically after whole-body doses of approximately 1–2 Gy, with the hematopoietic syndrome being the first to appear.
The hematopoietic syndrome of ARS primarily results from damage to which organ system?
Answer: Bone marrow and blood-forming cells
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.
According to the Law of Bergonié and Tribondeau, cells are most sensitive to radiation when they are:
Answer: Undifferentiated and rapidly dividing
Bergonié and Tribondeau established that cells are more radiosensitive when they are undifferentiated (immature) and have a high mitotic rate.
Which phase of the cell cycle is generally considered the most radiosensitive?
Answer: G2/M (late gap and mitosis)
Cells in G2 and M phase are most radiosensitive because DNA repair mechanisms are suppressed during mitosis and damage cannot be repaired before division.
The relative biological effectiveness (RBE) compares the biological damage of a test radiation to that of:
Answer: 250 kVp X-rays as the reference radiation
RBE is defined as the ratio of the dose of 250 kVp X-rays to the dose of the test radiation needed to produce the same biological effect.
Radiation-induced cataracts are classified as which type of radiation effect?
Answer: Deterministic with a threshold dose
Cataracts are a deterministic (tissue reaction) effect with a threshold; the current ICRP threshold estimate is approximately 0.5 Gy for protracted exposure.