Biological effects to ionizing radiation

Question 1

Effects of ionizing radiation on DNA

Answer 1

• Single strand break
• Double strand break

Question 2

Single strand break

Answer 2

A scenario whereby ionizing radiation interacts with a DNA molecule and severs the sugar-phosphate chain at one part.

• injury called point mutation

Question 3

Single strand break effects

Answer 3

gene abnormality

Question 4

Double strand break

Answer 4

A scenario whereby the ionizing radiation severs the sugar phosphate chain at 2 points in the DNA molecule due to excessive exposure.

Question 5

Biological damages caused due to ionizing radiation.

Answer 5

• Stochastic effects
• Non-stochastic effects

Question 6

Stochastic effects

Answer 6

here the likelihood of damage caused is dependent to the amount of radiation exposure received.

Question 7

Non-stochastic effect

Answer 7

a minimum radiation dose is required for the effect to occur.

Question 8

characteristics of non-stochastic effects

Answer 8

• Mechanism is cell killing
• Has a threshold dose
• Deterministic in nature
• Severity increases with dose
• can be avoided
• causes skin burns, cataracts sterility

Question 9

non-stochastic effects can result into

Answer 9

• Erythema
• Cataracts
• Radiation damage to the gut

Question 10

Threshold doses for non-stochastic effects

Answer 10

Cataract of the lens of the eye - 2 – 10Gy
Permanent sterility males - 3.5 – 6Gy
females - 2.5 – 6Gy
Temporary sterility males - 0.15Gy
females - 0.6Gy

Question 11

Characteristics of stochastic effects

Answer 11

• Mechanism is cell modification
• No threshold
• Probabilistic in nature
• Cannot be avoided
• Chromosomal damage