SHEDDING LIGHT ON X-RAY RADIATION
Naturally-occurring and man-made radiation are constant, invisible parts of our daily lives. We cannot see, feel or experience radiation with our senses, but we are aware of its significant benefits and potential risks. Those risks are often the focus of our attention, since extremely high doses of certain radiation can lead to cancer or even death.
At Astrophysics we work with x-rays every day. We build security scanners that use x-ray energy sources to see through objects and find hidden threats like weapons, explosives and other contraband. We are experts on global radiation exposure regulations and practice proper radiation safety at all of our facilities. In this article we share our x-ray safety knowledge to help you better understand the benefits and risks of this powerful tool.
What are x-rays?
X-rays are a type of electromagnetic radiation that transmits as waves. Traditional x-ray machines rely on the transmission of these waves to see through particular objects. Alternatively, there is another type of x-ray imaging known as backscatter, which reflects from the object and forms an image. X-rays are invisible and odorless. Unlike other electromagnetic radiation, like visible light, we cannot detect x-rays with our senses. We cannot see or smell x-rays, but they are all around us. We are exposed to this and other forms of natural radiation every single day, including certain foods (e.g. bananas), minerals buried in the earth (e.g. uranium), the Sun, and high-energy radiation from outside our solar system. All this daily background radiation is so miniscule that our bodies can easily absorb it.
After the discovery of x-rays by German scientist Wilhelm Roentgen in 1895, scientists quickly developed ways to use this new technology. Physicists like Marie Curie made discoveries that added to our understanding of radiation, noting how harmful unprotected exposure can be on our bodies. She also developed one of the earliest portable x-ray scanners, used to diagnose battlefield injuries during World War I. Today, sophisticated imaging software, like that used in Astrophysics x-ray scanners, translates x-ray absorption data into the images we use in medical and security screening. Each new x-ray development also brought new techniques for limiting our radiation exposure, ensuring we used these tools safely and effectively.
How do we use x-rays?
Today, x-rays are used in a variety of industries such as medicine, astronomy, security and defense. Doctors and dentists use x-rays to examine areas inside our bodies. Besides checking broken bones and reviewing dental records, x-rays can help identify illnesses (pneumonia from a chest x-ray) and cancers (breast cancer from a mammogram). At low doses, radiation is used in x-rays to see inside your body. At high doses, x-ray radiation therapy kills cancer cells and slows their growth by damaging their DNA.
In the security industry, we use x-rays to see through objects and detect hidden threats including weapons, explosives, and other contraband. The items we see through can be smaller than a sewing needle and as large as a truck. Our Astrophysics x-ray security scanners see through objects while emitting very little radiation to operators and nearby persons.
Security companies also use other forms of ionizing radiation, such as backscatter and millimeter wave, to do full body inspections. Typically employed in airport body scanners, these systems generate images of an individual’s entire body to screen for threats. Using this technology has led to concerns around protecting people’s privacy and their health, with many airports allowing passengers to opt out of backscatter screenings.
X-rays also help us explore the farthest reaches of our galaxy. Known as x-ray astronomy, this branch of science observes and detects astronomical objects via x-ray radiation, allowing astronomers to see further into space than they can using standard light-absorption telescopes.
How do we measure x-ray exposure?
Customers often ask: What is the likelihood of ever being exposed to dangerous levels of radiation? The short answer: Extremely unlikely. When you compare radiation exposures across different activities, it is easy to understand why.
The universal unit for an absorbed dose of radiation is a Sievert (Sv). One (1) Sv is considered dangerous; two (2) Sv is considered deadly and can result in severe radiation poisoning. Our bodies absorb small amounts of radiation on a daily basis. The amounts are so small, in fact, that they are usually measured in very tiny units: millisieverts (mSv) and micro-Sieverts (µSv):
1 Sievert = 1,000 millisieverts (mSv) = 1,000,000 microsieverts (µSv)
The chart below shows average exposure levels for various activities, including x-ray scans. The top of the chart shows how much radiation our bodies absorb when going through airport backscatter systems. Astrophysics’ largest vehicle scanners emit as much radiation as eating a banana. This means an individual would need to drive through our HXC-LaneScanTM portal more than 800 million times to reach dangerous exposure levels.