P4 Irradiation and Contamination (page 199)

Question 1

Ionising radiation can enter what cells?

Answer 1

living cells and ionise atoms within them.

Question 2

If ionising radiation can enter living cells, what can happen?

Answer 2

this can damage the cells (which can cause things like cancer) or kill them off completely.

(that is why it;s important that you know the precautions to take when working with any sources of radiation.

Question 3

Exposure to Radiation is called?

Answer 3

Irradiation

So objects near a radioactive source are irradiated by it. This simply means they’re exposed to it.

Question 4

Do irradiating somthing make it radioactive?

Answer 4

no. (and it won’t turn you into a superhero)!

Question 5

What are the common ways of reducing the effects of irradiation?

Answer 5

Keeping sources in lead-lined boxes and standing behind barriers.

(in some industries, the source may be in a different room and remote-controlled arms are used to handle it).

Question 6

What is contamination?

Answer 6

contamination is radioactive particles getting onto objects.

If unwanted radioactive atoms get onto or into an object, the object is said to be contaminated.

E.g. if you touch a radioactive source without wearing gloves, your hands would be contaminated.

Question 7

What happens with contaminating atoms?

Answer 7

they might decay, releasing radiation which could cause you harm.

Question 8

Why is contamination dangerous?

Answer 8

because radioacive particles could get inside your body.

Question 9

How can you protect yourself when handling contaminated sources?

Answer 9

Gloves and tongs should be used when handling sources to avoid particles getting stuck to your skin or under your nails.

(some industrial workers wear protective suits to stop them breathing in particles).

Question 10

Contamination or irradiation can cause different amounts of harm, based on what?

Answer 10

the radiation type.

Question 11

Outside the body, what sources of radiation are the most dangerous? and why?

Answer 11

Beta and Gamma sources, this is because Beta and Gamma can penetrate the body and get to the delicate organs.

Question 12

Why Alpha radiation less dangerous than Beta and Gamma radiation?

Answer 12

Alpha is less dangerous because it can’t penetrate the skin and is easily blocked by a small air gap (see page 196)

Question 13

High levels of irradiation from all sources are dangerous, but they are especially dangerous from ones that emit what?

Answer 13

Beta and Gamma.

Question 14

When working with Alpha sources, why is this the most dangerous inside the body?

Answer 14

Inside the body, alpha sources are the most dangerous, because they do all their damage in a very localised area. So contamination, rather than irradiation, is the major concern when working with alpha sources.

Question 15

Beta sources are less damaging inside the body, why?

Answer 15

because the radiation is absorbed over a wider area, and some passes out of the body altogether.

Question 16

Gamma sources are the least dangerous inside the body why?

Answer 16

as they mostly pass straight out - they have the lowest ionising power (see page 196).

Question 17

Finish the sentence…

The move we understand how different types of radiation affect our bodies……

Answer 17

the better we can protect ourselves when using them.

(this is why it’s so important that research about this is published. The data is peer-reviewed (see page 1) and can quickly become accepted, leading to many improvements in our use of radioactive sources.

Question 18

State one way of preventing irradiation (1 mark)

Answer 18

E.g. Keeping sources in lead-lined boxes/standing behind shielding (1 mark)

Question 19

For a gamma source, is contamination or irradiation a larger concern? (1 mark)

Answer 19

Irradiation (1 mark)

(make sure you can describe how to prevent irradiation and contamination, and why it’s so important that you do).