Radiation in medicine/ background radiation

• What factors influence the danger of radiation exposure?

  The half life, the type of radiation, and its toxicity
• What is the definition of contamination?


  Contamination is the unwanted presence of materials containing radioactive isotopes on other materials.
• What is the definition of irradiation?


  Irradiation is the process of exposing an object to nuclear radiation.
• How is radiation used in medicine?


  Radiation can be used in medicine for both diagnosis and treatment.
• What is radiotherapy?


  Radiotherapy is the use of irradiation to kill cancer cells in the body.
• Why is Technetium-99 preferred for radioactive tracers?


  Because it has a short half-life and emits gamma radiation, which is the least ionising.
• How does a gamma knife work?


  Gamma rays are shot at the patient and intersect where the cancerous cells are, concentrating the radiation in one area.
• What is the average yearly dose of background radiation received by a person in the UK?

  The average person in the UK receives a yearly dose of 2.1 mSv.
• What are cosmic rays and where do they come from?

  Cosmic rays bombard the Earth from the sun and other sources in the universe.
• What are some sources of background radiation?

  Background radiation can come from radon gas, buildings, food and drink, cosmic rays, and nuclear power and testing
• Why do some people receive a higher dose of background radiation?

  Some people receive a higher dose due to living in areas with higher radon gas emitting rocks or frequent flying.
• What units are used to measure radiation exposure?

  Sierverts (Sv) are used to measure radiation exposure, while becquerels (Bq) measure general radioactivity.
• How can background radiation be accounted for in a room?

  By placing a Geiger-Muller tube in a room for periods of time, taking readings, and finding an average.
• What happens during nuclear accidents and weapons testing in relation to background radiation?

  Radioactivity is released during nuclear accidents and weapons testing, contributing to background radiation.
• How does radioactive tracer work?

  The patient swallows a tracer containing a radioactive isotope, and once it's inside the body it emits gamma radiation, which can be easily detected outside the body with a gamma camera. Changes in the amount of gamma emitted from different parts of the body would show how well the isotopes are flowing, or if there is a blockage. They have half lifes of a few hours and are not poisonous.
• Is a gamma knife contamination or irradiation?

  Irradiation
• Is a radioactive tracer a form of contamination or irradiation?


  Contamination
• Why don't the gamma rays used in a gamma knife harm the healthy cells?

  Because they come from lots of different directions so the tumour will receive a high dose of radiation whereas the healthy cells only receive a small dose.
• What can irradiation be used for?

  Sterilisation, radio therapy and food preservation using gamma rays.
• Irradiation can damage and mutate living cells but do not cause the irradiated object to become radioactive
• How is contamination used to check for leaks?

  Water supplies are contaminated with a gamma-emitting radioactive isotope to find leaks in pipes . Where there is a leak, contaminated water seeps into the ground, causing a build-up of gamma emissions in that area. The build-up of gamma emissions can be found using a Geiger-Muller tube. This makes it easier to decide where to dig to find the leak.
• What is the criteria for a isotope used to check for leaks in pipes?

  It must have a half life of a couple of days, emit gamma radiation, and not be poisonous.