Hazards and uses of radioactive emissions and of background radiation Key Terms

medical tracer

A radioactive substance used in medical imaging to track the movement of substances within the body.

half-life

The time required for half of the radioactive nuclei in a sample to decay.

half-life

The time taken for the radioactivity of a specified isotope to fall to half its initial value.

radioactive isotope

An isotope that has an unstable nucleus and emits radiation as it decays.

half-life

The time taken for the activity of a radioactive isotope to decrease to half its initial value.

activity

The rate at which a sample of radioactive material decays, measured in decays per second (Bq).

radioactive isotope

An isotope of an element that is unstable and can emit radiation as it decays.

half-life

The time required for half of the radioactive nuclei in a sample to decay.

isotope choice

The process of selecting a radioactive isotope based on its half-life and the balance between its usefulness and the risk of exposure.

exposure risk

The potential harm or danger associated with exposure to radioactive materials, which must be weighed against their benefits in applications.

radioactive tracer

A substance that emits radiation and is used to track the movement of materials within biological systems.

ionising radiation

Radiation that carries enough energy to liberate electrons from atoms or molecules, thereby ionising them.

gamma emitters

Radioactive isotopes that emit gamma radiation, commonly used in medical imaging due to their high penetration power and low ionising effect.

medical tracers

Substances containing radioactive isotopes used in medical diagnostics to visualize and follow the movement of substances within the body.

medical tracers

Radioactive substances used in medical imaging to follow the movement of substances inside the body.

half-life

The time taken for the radioactivity of a specified isotope to fall to half its original value.

radiotherapy

A medical treatment that uses ionising radiation to destroy cancer cells.

ionising radiation

Radiation that carries enough energy to liberate electrons from atoms or molecules, thereby ionising them.

radiotherapy

A medical treatment that uses ionising radiation to destroy cancer cells while minimizing damage to healthy tissue.

ionising radiation

Radiation that carries enough energy to liberate electrons from atoms or molecules, thereby ionizing them.

alpha radiation

A type of ionising radiation consisting of alpha particles, which are helium nuclei emitted by certain radioactive materials.

smoke alarm

A device that detects smoke as an indicator of fire, often using alpha radiation to ionize air and trigger an alarm when smoke disrupts the ionization.

ionisation smoke alarm

A device that detects smoke by measuring changes in electrical current caused by smoke particles entering the ionisation chamber.

current change

The alteration in the flow of electric charge in a circuit, which can trigger an alarm in smoke detection systems.

gamma radiation

A type of high-energy electromagnetic radiation used in various applications, including medical imaging and sterilisation.

beta radiation

A type of radiation consisting of beta particles, which are high-energy, high-speed electrons or positrons, used in thickness monitoring and other applications.

beta radiation

A type of ionising radiation consisting of high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei.

thickness-control systems

Systems that use radiation to measure and control the thickness of materials during manufacturing processes.

gamma radiation

A type of high-energy electromagnetic radiation used in medical applications, including sterilisation of equipment.

sterilisation

The process of eliminating all forms of bacteria and other microorganisms from a surface or object, often using gamma radiation.