Hazardous Effects Of Radiation (AQA GCSE Combined Science: Synergy: Life & Environmental Sciences): Revision Note

Tissue Damage

Hazardous effects of ionising radiation

• The following types of ionising radiation have hazardous effects on human bodily tissues:

  • Ultraviolet (UV) waves

  • X-rays

  • Alpha particles

  • Beta particles

  • Gamma rays

• UV radiation in particular can cause:

  • Skin cancer

  • Sunburn and blistering

  • Damage to eyes (including cataracts)

  • Premature skin ageing

• The hazardous effects depend on:

  1. The type of radiation

  2. The size of the dose

How radiation damages tissue

• Ionising radiation turns atoms into ions and breaks up molecules

• This can cause changes to DNA in cells

• Changes to DNA cause mutation of genes, which may lead to cancer

• High-energy gamma rays can also be used to destroy cancer cells in the treatment of cancer

Cancer

• Cancer is caused by changes in the DNA of cells that lead to uncontrolled growth and division

• Tumours form when cells start growing and dividing in an uncontrolled way

• There are two types of tumour:

  1. Benign tumours

     • These are contained in one area, usually within a membrane

     • They do not invade other parts of the body

  2. Malignant tumours

     • These invade neighbouring tissues and spread to different parts of the body in the blood, where they form secondary tumours

Minimising Risk from Ionising Radiation

• Precautions can be taken to reduce the risk of exposure to ionising radiation:

  • Wear safety glasses and gloves when handling sources

  • Handle sources with tongs — never with bare hands

  • Keep distance from the source; never point it at people

  • Use lead shielding to absorb radiation

  • Keep the source out of its container for the minimum time necessary

  • Radiation workers wear dosimeters to monitor their total exposure