Radiation or ultraviolet light sterilization: this method is expensive. But nowadays it is used for the sterilization of plastic items such as disposable saline set, catheter, Ryle’s tubes, etc

Gas sterilization: ethylene oxide gas is employed as a sterilizing agent in especially designed chambers in which temperature and humidity can be controlled and from which air can be evacuated

After exposure period of 3 to 6 hours is needed. Other gases employed for sterilization are formaldehyde and betapropiolatone

Articles Sterilized

  • Surgical instruments with optical lenses
  • Tubing and plastic parts of heart lung machines
  • Ventilator tubes
  • Disposable syringe
  • Pillows and mattresses


  • Exposure to formaldehyde gas under conditions of controlled humidity, temperature, and the time exposure will destroy all vegetative forms of bacteria, viruses, and most of the spores
  • The best results can be obtained with high concentration of gas humidity above 60% and temperature of not less than 180 degree celcius


  • Ethylene oxide has a pungent smell
  • It is an irritant to eye, mucous membrane and skin

Radiation Method

There are two type of radiation are non-ionizing radiation and ionizing radiation

Non-ionizing radiation methods are infra-red and ultra-violet radiation

Ionizing radiation methods include X-rays, gamma rays; and cosmic rays are highly lethal to DNA and other vital cell constituents


  • Instruments like disposable syringe catheters hypo-dermic needles and sharp instruments that cannot withstand heat, can be sterilized by this method
  • Instruments which are covered in plastic packs or aluminum foils can be sterilized by this method


  • Since radiation in a straight line and do not penetrate only the surface of an object in straight line is irradiated
  • The bacteria in shadows are unaffected, so all the surfaces should be exposed to the radiation
RADIATION METHOD OF STERILIZATION - Gas & Radiation sterilization, advantages , disadvantages
RADIATION METHOD OF STERILIZATION – Gas & Radiation sterilization, advantages , disadvantages

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