Uses and hazards of radiation for OCR A-level Physics
This page covers the following topics:
1. Uses of radiation
2. Radiation hazards to humans
Different types of radiation have different uses. Alpha radiation is used in smoke detectors by ionising the air inside it. In the case of a fire, the smoke will disrupt the ionisation and turn the alarm on. Beta radiation is used in medical imaging. Radiation will gather around damaged organs and detectors will be able to detect the radiation being emitted, and thus an internal image is constructed. This is also achieved through the use of gamma radiation. The isotope injected into the body will emit gamma rays outside it and a detector will be able to follow its path to be able to identify any soft tissue or blockages inside the body. Such radioactive sources used in medical imaging are called tracers. Gamma radiation is also used for cancer treatment by killing cancer cells, and the sterilisation of medical equipment by killing bacteria.
Both ionising and non-ionising radiation can be hazardous. Ionising radiation can penetrate the body and has enough energy to impact cells. This radiation can damage their genetic material. If this is not repaired correctly, the affected cells could die or become cancerous. Non-ionising radiation may cause damage to any exposed body parts by heating them, and thus possibly causing burns. Exposure to low levels of radiation are small, but may contribute to one's overall risk to cancer, unlike exposure to high levels, which could cause immediate and strong effects.
How can beta radiation be used in medical imaging?
A radioactive source will be injected into the body. Radiation will gather around damaged organs and detectors will be able to detect the beta radiation being emitted out of the body, and thus an internal image is constructed.
Describe how ionising radiation may cause cancer.
Ionising radiation has enough energy to damage the genetic material of a cell. If the cell is not repaired correctly, it may become cancerous.
Define what is meant by a tracer.
Tracers are radioactive sources injected into the body for medical imaging and tracing purposes.
Describe the process by which medical equipment is sterilised.
Gamma radiation is used to sterilise equipment through irradiation, since it will kill the bacteria on them.
What characteristic of alpha radiation allows it to be used in smoke detectors?
The ionising property of alpha radiation is what allows it to be used in smoke detectors.
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