Treatment

Question 1

Radiation emitted from the nucleus of an unstable atom can be alpha, beta, or gamma.

Answer 1

• Alpha radiation is absorbed by the skin so is of no use for diagnosis or therapy.
• Beta radiation passes through the skin, but no bone. Its medical applications are limited but it is used, for example, to treat the eyes.
• Gamma radiation is very penetrating and is used in medicine. Cobalt-60 is a gamma-emitting radioactive material that is widely used to treat cancers.

Question 2

What causes ionisation?

Answer 2

When nuclear radiation passes through a material it causes ionisation. Ionising radiation damages living cells, increasing the risk of cancer

Question 3

Radiotherapy

Answer 3

Cancer cells within the body can be destroyed by exposing the affected area to large amounts of radiation. This is called radiotherapy.

Question 4

Making materials radioactive

Answer 4

Materials can be made radioactive when their nuclei absorb extra neutrons in a nuclear reactor.

Answer 5

When x-ray pass through the body the tissues absorb some of this ionising radiation. The amount absorbed depends on the thickness and the density of the absorbing material

Question 6

Gamma rays and X-rays

Answer 6

Gamma rays and x-rays have similar wavelengths but are produced in different waves.

Question 7

How are x-rays made?

Answer 7

X-rays are made by firing high speed electrons at metal targets.

Question 8

X-ray machines and Gamma Rays

Answer 8

• An x-ray machine allows the rate of production and the energy of the x-rays to be controlled, but you can’t change gamma radiation emitted from of a particular radioactive source.
• When the nucleus of an atom of radioactive substance decays, it emits an alpha or a beta particle and losers any surplus energy by emitting gamma rays.

Question 9

A radioactive tracer is used to investigate inside a patient’s body without surgery.

Answer 9

• Technetium 99m-is a commonly used tracer. it emits only gamma radiation.
• Iodine-123 emits gamma radiation. It is used as a tracers to investigate the Thyroid gland.
• The radioactive tracer of being used as mixed with food or drink injected into the body.
• Its progress through the body is monitored using a detector such as a gamma camera connected to a computer.

Question 10

Treating cancer

Answer 10

• A radioisotope is used to destroy a tumour in the body.
• Three sources of radiation, each providing one-third of the required dose, are arranged around the patient with the tumour at the centre.
  
  • The healthy tissue only receives one-third of the dose, which limits damage to it.
• Or each radiation source is slowly rotated around the patient. The tumour receives constant radiation but healthy tissues recieves only intermittent doses.