Why Does Lead Block Radiation?

If you’ve had an x-ray before, then you probably wondered why the technologist had you wear a heavy lead covering. Whether it was a dental radiation protection apron during a dental x-ray or a thyroid guard during another procedure, these protective garments were meant to protect you from the harmful effects of radiation. 

Why Does Lead Stop Radiation? 

Our engineers at Barrier Technologies develop and manufacture industry-leading radiation protective garments like lead aprons and thyroid shield covers. And while most of our blog readers are already well-versed in the ins and outs of how lead stops radiation, we do occasionally get readers who are still figuring out how radiation works. 

If you are new to the exciting world of x-ray protection and you’ve come here wondering, “How does lead block radiation?” then this is the crash course you’ve been looking for. 

Continue reading to learn exactly how lead protects you from x-rays.

How Does X-Ray Radiation Work? 

Before diving into how lead blocks radiation, it would be helpful for you to understand how x-ray radiation works. 

X-rays are a kind of electromagnetic wave — a spectrum of energy waves that includes visible light, microwaves, and even radio waves. X-rays are created when a negatively charged electrode is heated, releasing electrons. These electrons, in turn, release energy, which is emitted in the form of x-rays. 

How X-Rays Penetrate Matter

X-rays are powerful enough to penetrate many kinds of matter, including the human body. And just like how light from the sun can pass through certain materials (like paper) and not others (like solid walls), x-rays also have an easier time passing through some materials over others. 

What determines whether or not an x-ray can easily pass through an object is the atomic density of its elements. Bones are full of calcium, a dense element with a high atomic number, while flesh, muscle, and organs are composed of lighter elements like carbon, oxygen, and hydrogen. 

The ability of an element to block radiation is called “attenuation.” So to put the above paragraph another way — bones have a higher attenuation than muscle and organs. 

So as a beam of x-rays pass through an object, it creates a silhouette on the other side — a kind of inverted shadow, where the light parts of the x-ray reveal where radiation waves were blocked and the darker parts of the image show where x-rays had no trouble passing through the object. 

Why X-Ray Radiation is Harmful

As x-ray radiation passes through a body, the radiation waves collide with atoms, knocking electrons out of orbit. This can turn the atom into an ion or an electrically charged atom, 

Atoms that are damaged by radiation become disruptive, moving haphazardly inside cells. This can cause damage to molecules and damage to the DNA inside cell nuclei. 

While the average patient has nothing to fear from the occasional x-ray (the damage done to cells is too small to create any real impact), people who are repeatedly exposed to high radiation levels or who are continually bombarded with x-rays and scatter radiation can be harmed. 

This is because radiation has a cumulative effect on the body. Unlike other injuries that heal over time, radiation damage is permanent. So with each new exposure, the number of damaged atoms increases until there is finally enough disruption to create an actual condition (cataracts, radiation burns, and cancer). 

To help protect the body from excess radiation exposure, healthcare professionals and patients wear xray lead aprons. And this brings us back to the question we’re here to answer: why does lead block radiation? 

How Does Lead Block Radiation?

Similar to how bones block more x-rays than organs due to the heavyweight of calcium, lead is excellent at attenuating radiation waves thanks to its immense atomic mass. 

Compared to calcium’s atomic mass of 40, lead has a density of 207. 

But how does this help lead aprons to stop radiation? 

The higher the atomic number of an element, the tighter its atoms are packed together. So while x-rays can fly through carbon, which has an atomic mass of 12 (and thus, lots of empty space), x-rays have a much harder time penetrating lead’s mass of 207. 

To help you picture how this works, here’s a quick analogy.

Imagine you have to kick a ball across an empty field. This would be pretty easy, as nothing is blocking the ball from reaching the other side. 

But now imagine that I cover the field in hundreds of traffic cones. The ball will probably get blocked by a cone and won’t make it to the other side as its energy will be transferred to the cone — stopping the ball. 

To summarize, why does lead block radiation? In simple terms: the tightly packed atoms in lead block the x-rays from reaching the other side. 

Alternatives to Lead Radiation Protection

While lead is extremely effective at blocking radiation, it’s a difficult material to work with, as lead garments (e.g., aprons and collars) are heavy, cumbersome, and difficult to clean. Even worse, lead is a toxic substance that isn’t environmentally friendly and requires specialized disposal. 

For decades, the healthcare industry has been forced to endure these downsides as lead was the only material able to effectively attenuate radiation — that is, until quite recently. 

In the 1990s, medical manufacturing companies, like Barrier Technologies, began to experiment with alternative attenuation techniques, creating specialized metal material with the same level of attenuation as lead while also being much lighter. 

Our lead-free attenuation material is an amalgamation of metal alloys, including bismuth and titanium. And because these metals have a smaller atomic weight than lead, our aprons and thyroid guards are between 30-40% lighter than their lead counterparts (while still being equally effective at stopping radiation). 

Where to Find Advanced Radiation Protection Products 

So, why does lead block radiation? Lead blocks radiation due to the density of its atoms and high attenuation. But while lead is an excellent material for radiation protection garments, it isn’t the only solution available. 

If you are looking for lightweight x-ray aprons or thyroid shields, then take advantage of Barrier Technologies’ innovative Pb-free attenuation material. 

Contact us today to learn more about our wide range of protective garments, shields, and drapes.