RAD 205 Ch. 8 Review

Early tissue reactions are also known as:

• Stochastic effects

• Deterministic effects

• Somatic effects

• Genetic effects

Answer explanation

Early tissue reactions are known as deterministic effects because they have a threshold dose and severity increases with dose. In contrast, stochastic effects occur randomly and do not have a threshold.

Deterministic effects typically occur when:

• Any dose is received

• Low doses accumulate

• A threshold dose is exceeded

• Indirect DNA damage occurs

Answer explanation

Deterministic effects occur when a threshold dose is exceeded, meaning that only after a certain level of exposure do these effects manifest. This distinguishes them from stochastic effects, which can occur at any dose.

Which characteristic defines a deterministic effect?

• Random occurrence

• Severity increases with dose

• No threshold exists

• Long latent period

Answer explanation

A deterministic effect is characterized by the severity of the effect increasing with the dose received. Unlike stochastic effects, which occur randomly, deterministic effects have a clear dose-response relationship.

What is a common example of a deterministic effect?

• Cancer

• Genetic mutation

• Skin erythema

• Leukemia

Answer explanation

Skin erythema is a common deterministic effect of radiation exposure, characterized by skin reddening. Unlike cancer or genetic mutations, which are stochastic effects, deterministic effects have a clear threshold and severity increases with dose.

Which of the following is an early tissue reaction?

• Cataracts

• Cancer

• Epilation

• Genetic damage

Answer explanation

Epilation is an early tissue reaction to radiation exposure, characterized by hair loss. In contrast, cataracts, cancer, and genetic damage are considered late effects, occurring after a longer latency period.

The severity of early tissue reactions:

• Is independent of dose

• Decreases with increased dose

• Increases as dose increases

• Is random

Answer explanation

The severity of early tissue reactions increases as the dose increases. Higher doses lead to more significant biological effects, making this the correct choice.

What term describes hair loss due to radiation exposure?

• Necrosis

• Epilation

Answer explanation

The term 'epilation' specifically refers to hair loss, which can occur due to various factors, including radiation exposure. 'Necrosis' refers to tissue death, not hair loss.

What radiation exposure can result in early tissue reactions?

• Low-dose dental x-rays

• Repeated small exposures

• High-dose, whole-body exposure

• Background radiation

Answer explanation

High-dose, whole-body exposure can lead to early tissue reactions due to the significant amount of radiation absorbed, which can cause immediate biological effects. Other options involve lower doses that typically do not result in such reactions.

Which organ system is most sensitive to radiation?

• Skeletal

• Nervous

• Hematopoietic

• Muscular

Answer explanation

The hematopoietic system, responsible for blood cell production, is highly sensitive to radiation due to its rapid cell turnover. Radiation can severely impact bone marrow, leading to significant health issues.

Skin erythema usually appears at what radiation dose?

• 0.1 Gy

• 0.5 Gy

• 2.0 Gy

• 10 Gy

Answer explanation

Skin erythema typically appears at a radiation dose of 2.0 Gy. This dose is significant enough to cause visible skin reactions, while lower doses like 0.1 Gy and 0.5 Gy usually do not result in erythema.