Uses of Radiation

Medical Uses of Radiation

Radiation has many important applications in medicine, especially in diagnosis and treatment.

Radiotherapy for Cancer Treatment

Radiotherapy uses high doses of ionising radiation, such as gamma rays, to kill cancer cells or stop them dividing. The radiation is carefully targeted to minimise damage to surrounding healthy tissue. Gamma rays are used because they can penetrate deep into the body and effectively damage cancer cells.

Medical Imaging

X-rays are a form of ionising radiation used to create images of bones and internal organs. They pass through soft tissues but are absorbed by denser materials like bones, producing a contrast image on photographic film or digital detectors.

Radioactive tracers are substances containing radioactive isotopes, such as technetium-99m, that emit gamma rays. They can be injected or swallowed and tracked inside the body using special cameras. This helps doctors observe organ function and detect abnormalities.

Sterilisation of Medical Equipment

Gamma radiation is used to sterilise surgical instruments and other medical equipment. It kills bacteria and other pathogens without the need for heat or chemicals, ensuring equipment is safe for use. Gamma rays are ideal because of their strong penetration and ability to kill microorganisms effectively.

For instance, cobalt-60 emits gamma rays used in radiotherapy to target tumours deep inside the body without surgery.

Industrial Uses of Radiation

Radiation is widely used in industry to improve quality control, detect faults, and measure materials.

Thickness Gauging

Beta radiation is used to measure the thickness of materials like paper, plastic, or metal sheets during manufacturing. A beta source emits radiation through the material to a detector. The amount of radiation detected decreases as thickness increases, allowing precise control.

Radiotracers to Detect Leaks

Radioactive isotopes can be added to fluids in pipelines or tanks. Detectors placed outside the system can then locate leaks by detecting escaping radiation, helping prevent environmental damage and costly repairs.

Material Testing (Radiography)

Gamma rays or X-rays are used to inspect the internal structure of metal parts and welds without damaging them. This process, called radiography, reveals cracks or faults that could cause failure in critical components like bridges or aircraft.

Example: In a factory, a beta source emits radiation through a moving plastic film. The detector measures radiation intensity to ensure the film thickness stays constant, preventing waste or product defects.

Agricultural Uses of Radiation

Radiation helps improve food safety and crop production in agriculture.

Food Irradiation to Kill Bacteria

Gamma rays are used to kill bacteria and other microorganisms in food, extending shelf life and reducing the risk of food poisoning. This process does not make the food radioactive.

Mutation Breeding to Improve Crops

Exposure of seeds to radiation can cause mutations, some of which may produce plants with desirable traits such as higher yield or disease resistance. These mutated plants are then selectively bred to develop improved crop varieties. However, many mutations are harmful or neutral, so careful selection is necessary.

Scientific and Other Uses

Radiation has several important uses in science and everyday devices.

Carbon Dating for Age Determination

Carbon-14, a radioactive isotope, is used to estimate the age of once-living materials like fossils or archaeological samples. The amount of carbon-14 remaining compared to the original amount indicates how long ago the organism died.

Example: If a sample has half the carbon-14 it originally had, its age is approximately one half-life of carbon-14 (about 5730 years).

Smoke Detectors Using Alpha Radiation

Many smoke detectors contain a small amount of americium-241, which emits alpha particles. These particles ionise air inside the detector, allowing a small current to flow. Smoke particles disrupt this current, triggering the alarm.

Safety and Hazards

When using radiation, safety precautions are essential to protect people from harmful effects. This includes shielding with lead or concrete, limiting exposure time, and maintaining distance from sources. Proper training and monitoring help reduce risks associated with ionising radiation.