P4 - Treatment using radiation
- Created by: Naomi
- Created on: 21-01-13 21:50
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- Treatment using radiation
- Using radiation
- Radiation emitted from the nucleus of an unstable atom can be alpha, beta or gamma
- Alpha radiation is absorbed by the skin, so is of no use for diagnosis or therapy
- Beta radiation passes through the skin, but not bone. Its medical applications are limited but it is used
- Gamma radiation is very penetrating and is used in medicine. Cobalt-60 is a gamma-emitting radioactive material that is used to treat cancers
- When nuclear radiation passes through a material, it causes ionisation
- Ionising radiation damages living cells, increasing the risk of cancer
- Cancer cells within the body can be destroyed by exposing the affected area to large amounts of radiation
- Radiation emitted from the nucleus of an unstable atom can be alpha, beta or gamma
- Comparing x-rays and gamma rays
- When x-rays pass through the body the tissue absorbs some of the ionising radiation
- The amount absorbed depends on the thickness and the density of the absorbing material
- Gamma rays and x-rays have similar wavelengths but are produced in different ways
- X-rays are made by firing high speed electrons at metal targets
- An x-ray machine allows the rate of production and energy of the x-rays to be controlled
- You can't change the gamma radiation emitted from a particular source
- An x-ray machine allows the rate of production and energy of the x-rays to be controlled
- When the nucleus of an atom of a radioactive substance decays, it emits an alpha or beta particle and loses any surplus energy by emitting gamma rays
- You can't change the gamma radiation emitted from a particular source
- X-rays are made by firing high speed electrons at metal targets
- When x-rays pass through the body the tissue absorbs some of the ionising radiation
- A radioactive tracer is used to investigate inside a patient's body without surgery
- The radioctive tracer is mixed with food or drink or injected into the body
- Its progress through the body is monitored using a detector such as a gamma camera connected to a computer
- Treating cancer
- 3 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 the damage to it
- Each radiation source is rotated around the patient
- The tumour receives a constant dose, but the healthy tissue only receives intermittent doses
- 3 sources of radiation, each providing one third of the required dose, are arranged around the patient with the tumour at the centre
- Using radiation
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