Radioactivity‎ > ‎

Usage of radioactive isotopes

Medical and  industrial use of radioactive isotopes

2- Smoke detector:

Type of radiation

  The isotope that is used
The properties that make it suitable for the application

 1- alpha is the most ionizing radiation

2- Alpha radiation is very easily stopped so no alpha radiation 

passes out of the smoke detector casing.

YouTube Video


The alpha particles pass between the two charged metal plates, causing air particles to ionize (split into positive and negative ions). The ions are attracted to the oppositely charged metal plates causing a current to flow.


When smoke enters between the plates, some of the alpha particles are absorbed causing less ionization to take place. This means a smaller than normal current flows so the alarm sounds.

3- Sterilizing equipment

Surgical instruments are sterilized using high doses of gamma radiation from radioactive cobalt.

Type of radiation
  The isotope that is used
 The properties that make it suitable for the application
Gamma rays

penetrating and ionizing power of gamma radiation

Gamma rays are high energy electromagnetic waves which are only stopped by thick lead. This means they can 

easily pass through medical equipment, such as syringes. As gamma rays pass through the packaging they will kill 

living tissue such as viruses and bacteria. As long as the equipment remains in a sealed plastic pack it will remain 

free of viruses and bacteria.

YouTube Video

4- Radiotherapy:

 is therapy using ionizing radiation, generally as part of cancer treatment to control or cancer cells. Radiation therapy may be curative in a number of types of cancer if they are localized to one area of the body

  Type of radiation
  The isotope that is used
The properties that make it suitable for the application

Iodine 131

 ionizing but with low penetration, so it can be focused on cancerous cells

YouTube Video

 For other  uses watch this video  

YouTube Video

YouTube Video

Radiation safety

yellow circle with 3 black pie shaped segments inside

Radiation warning symbol

You cannot do much to reduce your exposure to natural background radiation, but great care is 

needed when handling radioactive materials. Precautions include:

1- wearing protective clothing (gloves) made of lead 

2- handling radioactive materials by using tongs

3- keeping your exposure time as short as possible

4-  keeping radioactive materials in lead-lined containers.

5-  label radioactive materials with the appropriate hazard symbol.

6- Having short exposure time.

7- keeping a safe distance.