Radiation interaction with cells

Question 1

What is caused by ionising radiation hitting a cell

Answer 1

Excitation and ionisation of the cell produced within critical macromolecules (target cells, DNA) Or in the medium where the cellular organelles are suspended like water

Question 2

How are direct effects caused

Answer 2

when ionising radiation (usually high LET) hits the target cell. This may cause temporary or permanent changes to the cell functions.

Question 3

How are indirect effects caused

Answer 3

When the critical site is damaged by ionisation produced somewhere else in the cell like in the water which in turn damages the target.

Question 4

What is radiolysis of water

Answer 4

Radiolysis of water refers to the chemical process in which water molecules are broken down into reactive species (like free radicals) by ionizing radiation. When radiation interacts with water, it can cause the ejection of electrons from water molecules, leading to the formation of hydroxyl radicals (·OH), hydrogen atoms (H·), and other species. This process is significant in radiobiology, as these reactive species can further interact with biological molecules, leading to cellular damage and contributing to the effects of radiation exposure.

Question 5

what happens to radiolysis events if LET is low

Answer 5

there will be spacing between radiolysis events

Question 6

what happens to radiolysis events if LET is High

Answer 6

More likely to cause H202 production and thus damage is more likely

Question 7

How does direct ionisation cause damage

Answer 7

through direct ionisation of the target

Question 8

How does indirect ionisation cause damage

Answer 8

through the production of free radicals from the ionisation of water