This lesson will talk about ionizing and non-ionizing radiation, what they’re used for and what the different types are. For example, we’ll touch base on gamma irradiation, electron irradiation, x-ray irradiation and U.V.
Radiation is a scary word. We’ve all seen the movies that show how radiation creates three-eyed fish, or how it causes tumors to grow on the side of someone’s head. And, while the dangers of radiation are very real, radiation can actually be used to our benefit. That’s because it’s not just the fish and people that may suffer from the damaging effects of radiation – it’s the things we can’t see, such as harmful bacteria and viruses, that may suffer as well.
Sterilization Using Ionizing Radiation
One way in which sterilization by way of irradiation may occur is when ionizing radiation is used.
In the context of sterilization, ionizing radiation is a type of short wavelength, high intensity radiation that is used to destroy all microorganisms during sterilization. The forms of ionizing radiation used for sterilization are known as gamma irradiation, electron irradiation and x-ray irradiation.The precise, physics-based details of each type of radiation are best left for a physics lesson. What you should know is that this ionizing radiation produces disruptions in subatomic particles involved in the formation of the microorganism. In normal person speak, this means that the ionizing radiation directly or indirectly causes damage to the genetic material – DNA or RNA – inside of the microorganisms. If the DNA or RNA is damaged, the cell will die.
Even more simply, this radiation damages the hard drive of a bacterial computer, causing it to shut down for good.Using irradiation to sterilize something is great if the object you’re trying to sterilize is sensitive to the extreme heat created by something like an autoclave. However, using ionizing radiation for sterilization isn’t always practical in real life, and the FDA has not cleared any ionizing radiation sterilization techniques for healthcare facilities.
There are numerous reasons for this and for why many facilities wouldn’t want to use this method of sterilization in the first place. First of all, it’s expensive. Secondly, it may actually damage some of the material it’s trying to sterilize. And, third of all, it’s dangerous. If it can kill bacteria, you better believe it can kill you as well if it’s used improperly.
Disinfection Using Non-Ionizing Radiation
The alternative to ionizing radiation has a kind of anti-climactic name. It’s called non-ionizing radiation. This is a long wavelength, low energy, low penetration radiation used for disinfection or superficial sterilization. One type of non-ionizing radiation is called U.V. radiation.
Non-ionizing radiation in the form of U.V. radiation isn’t considered to be a good sterilant, meaning it can’t kill every living organism it targets because it is a relatively weak form of irradiation that cannot always get every type of organism. Therefore, it’s more of a disinfectant, or something used to kill most, but not all, living organisms on an inanimate object, or it is at the very best a superficial sterilant. That’s because near U.V.
radiation cannot penetrate below the surface of anything. It’s only good for disinfection or sterilization of things like the surfaces of tables or any relatively dust-free air in a room.For example, imagine you were a bacterium crawling along the surface of a table.
If you knew that someone was going to use a U.V. lamp to try and kill you, then you would jump into a microscopic crack on the surface of the table in order to protect yourself.
That crack will serve as a sort of cave where no light can penetrate into it. If no U.V.
light reaches you in that crack, you’ll be completely safe from the destructive effects of non-ionizing U.V. radiation.Keeping that in mind, I’m sure you’ve seen toothbrushes being sold with U.V. sanitizers as part of the deal. Well, if the manufacturer is using safe levels of U.
V. radiation to sanitize the toothbrush, the radiation will only get the microorganisms at the very surface of the toothbrush. Deeper down, where the organisms are shielded by the bristles, they remain unharmed.You shouldn’t be surprised then, that one study showed that using hydrogen peroxide for reducing the number of bacteria located on a toothbrush was actually more effective than a toothbrush with a U.V. sanitizer.
In any case, U.V. radiation works by causing a similar end result as ionizing radiation; namely, the destruction of nucleic acids of microbial cells, resulting in their death.
So, let’s review the methods of radioactive destruction we can use on disease-causing microorganisms, or any microbes for that matter. One way in which sterilization by way of irradiation may occur is when ionizing radiation is used. In the context of sterilization, ionizing radiation is a type of short wavelength, high intensity, low temperature radiation that is used to destroy all microorganisms during sterilization.The forms of ionizing radiation used for sterilization are known as gamma irradiation, electron irradiation and x-ray irradiation.
The alternative to ionizing radiation has a kind of anti-climactic name. It’s called non-ionizing radiation. This is a long wavelength, low energy, low penetration radiation used for disinfection or superficial sterilization. One type of non-ionizing radiation is called near U.
V. radiation and it’s useful for the disinfection or sterilization of things like air or table surfaces.
When you have completed this lesson, you should be able to:
- Differentiate between ionizing and non-ionizing radiation
- Recognize the three types of ionizing radiation
- Explain how ionizing radiation kills microorganisms
- List some of the dangers of ionizing radiation
- Describe some of the drawbacks of using non-ionizing radiation, such as U.V. radiation, as a sterilant