Lesson 9 + 10 - Uses of Radioactivity

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What is radiotherapy?

radiotherapy is a treatment where radiation is used to kill cancer cells

What are two examples of radiotherapy?

gamma knife, brachytherapy beta implant

What is the aim of gamma knife?

to kill cancerous cells or remove unwanted tissue from the body

How does gamma knife work?

gamma rays are aimed at the tumor from different directions, the patient is held in place so they can’t move and the tumor cells reciece a high dose of radiation

Whats does gamma knife use?

the sources emits gamma rays, because they rays need to be able to penetrate into the body

Does the gamma knife have a long or short half life?

the source has a long half life so the machine can work for many years

What are the risks of gamma knife?

ionising radiation damages healthy cells in the patient

How do they reduce the risks of gamma knife?

• gamma rays are sent from different directions so the healthy cells recieve a lower raduatir dise but tumors recieve a higher radiation dose

• the doctor will also be shielded for the duration of the treatment

What is the aim of gamma knife?

to kill tumor/cancer

How does a beta implant work?

a radioactive source is implanted in the tumour, which usually emits beta and kills the cancer cells by damaging their DNA

What rays do they use for gamma knives?

beta because it needs to have a medium ionising power and not be too penetrating so the radiation is absorbed locally by the tumor

Does the beta implant have a long or short half life?

short, just for the duration of the treatment

What are the risks of beta implants?

damaging healthy tissues

How are risks minimised in a beta implant?

• having a shot half life, so the source is radioactive for not too long

• using a small amount of the source

What does a radioactive tracer do?

for diagnoses of cancer, which helps find out where the tumor or the other proble is, it is medical imaging

How do radioactive tracers work?

inject the patient with a radioactive tracer (a chemical used by a body with a radioisotope) and use a gamma camra to detect where the radiation comes from

What rays do they use for radioactive tracers?

gamma, so the radiaton can penetrate through the body (high penetration power)

Does a radioactive tracer have a long or short half life?

short half life, so the radioactive source is only in the body for a short time

Wat are the risks of radioactive tracers?

ionising radiation damages healthy cells and cause cancer

How are the risks of radioactive tracers minimised?

• don’t use this if pregnant

• use a hsort half life so the radioactive source is only inside the body for a short time

What does the aim of a smoke alarm?

it helps to alert people to potential fires or smoke by making a loud sound

How does a smoke alarm work?

smoke alarms use alpha particles from an alpha source, the alpha particles ionise air to create electron, the electron carry a current between two electrically chared plate

What rays do they use for smoke alarms?

alpha as it is the most ionising but the least penetrating 

Do smoke alarms have a long or short half life?

long so the smoke alarm doesn’t have to be replaced everyday

What are the risks of a smoke alarm?

a damaged smoke alarm can leak alpha particles

How are risks in a smoke alarm minimised?

keeping a smoke alarm unbroken