Lesson 4: Background radiation/ medicine

Question 1

Give two NATURAL sources of background radiation.

Answer 1

• Rocks
• Cosmic rays from space (very high energy particles that travel in space and crash into Earth’s atmosphere.)

( ) Extra

Question 2

Give two man- made sources of background radiation.

Answer 2

• Fallout of nuclear bombs when testing them (releases radioactive isotopes into environment)
• Nuclear accidents in power stations.

( ) - EXTRA

Question 3

What 2 factors does the level of background radiation and dose depend on?

Answer 3

1.) Location
2.) Occupation

Question 4

What is radiation dose measured in?

Answer 4

• Sieverts (Sv)
• 1000 milisieverts = 1 sievert

Question 5

EXAMPLE FSL…

A patient has an issue with their thyroid. Thyroid absorbs iodine to carry out its function. How would drinking a radioactive isotope of iodine allow the doctor to see whether the thyroid is working effectively?

Answer 5

• Thyroid absorbs radioactive iodine.
• And gamma radiation emitted from the source
• Gamma radiation passes out through body and allows doctor can see how much iodine has been absorbed.

Question 6

What 4 features must the radioactive tracer used in the exploration of internal organs have?

Answer 6

1.) The tracer must emit radiation that can pass out the body and be detected (beta/ gamma)
2.) The tracer musn’t be strongly ionising - minimise damage to tissue.
3.) Tracer musn’t decay into another radioactive isotope (will release different radiation.)
4.) Tracer must have short half- live so it isn’t present in the body for a long time.

Question 7

How is nuclear radiation used to control/ destroy unwanted tissue?

with source outside the body

Answer 7

• Cancers can be destroyed using ionsing radiation.
• This is called radiotherapy.
• Gamma radiation pass into the body and destroy the tumour.

Question 8

What is the issue with using nuclear radiation to control/ destroy unwanted tissue? How can this be solved?

with source oustide the body

Answer 8

• Healthy tissue may also be damaged as radiation passes through the body.
• Solution: Place radiation source inside the body, radiation targetted very precisely to tumour. Less damage to healthy tissue.

Question 9

Give an example of when a radiation source can be placed in the body to treat cancer.

Answer 9

• Radioactive rods inserted to treat prostate cancer.

Question 10

What two things are nuclear radiations used for in medicine?

Answer 10

1.) Exploration of internal organs.
2.) Control/ destruction of unwanted tissue.