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Types of X-Ray Sponges Explained

Written by Ryan Pryor on August 23, 2021
Category: X-Ray Positioning Sponges


Here's a quick explanation of the different types of x-ray positioning sponges. 

Coated Sponges VS Non-Coated Sponges 


A non-coated sponge is simply a bare piece of sponge cut into a particular shape. You could compare it to a standard kitchen sponge in that there is no coating, porous (absorbs liquid), and not very durable. These types of sponges exist because some applications and some facilities require nothing more than a basic piece of sponge. 


Most doctors' offices will rarely ever have a need for a positioning sponge. Since it is not a high commodity, they order basic (non-coated) sponges to keep costs as low as possible. Some facilities and usage require protecting the sponge from the absorption of liquids and bodily fluids. In the rare time that a doctor in a small practice uses a sponge and the patient bleeds on it, that sponge needs to be disposed of and they would have to order a new one. 


Any time you apply a coating to a sponge (a coated sponge) it will show up under x-ray. The chemical coating reacts with the imaging to show under x-ray. The higher the kilvoltage (Kv) applied to an image, the more you will see. A true technologist will know this and understand the proper levels of Kv to apply to an image. They are taught these concepts in school. 


Hospitals (and some other facilities) absolutely require all positioning aid products meet sanitary guidelines. In order to meet this standard, there are typically three types of positioning sponges that a hospital (or any place determined by regulations) can order: 

Three Types of Positioning Sponges 


The first type of x-ray positioning sponges are coated sponges. These are standard sponges coated with a protective chemical surface. The chemical surface preserves the pliability (flexibility) of the sponge but creates a non-porous surface. These can be wiped clean and are sanitary to use repeatedly. However, the outer coating is simply a chemical film. Under enough pressure or certain types of impact, the coating can rip and tear. 


The second x-ray sponge is vinyl covered sponges. These are firm foam shapes covered with a heavy-duty, vinyl material. These positioners are extremely durable with a cleanable, non-porous surface (think like a boat seat). Some manufacturers use "hook & loop" connections to close the vinyl over the foam. Though this will seal over the foam, it is not 100% sanitary like some bolsters are. 


The hook & loop does not have a sealed edge and liquid can absorb into the foam. The vinyl will also show seams under imaging, it all depends on the type of imaging as to the need for this type of product. Techno-Aide currently offers completely sealed seams on our bolsters.


Finally, closed cell sponges are relatively newer on the market than open cell sponges. However, they are currently the top-recommended type of imaging sponge. These positioners are made from a low density, non-porous, highly durable foam like a high-quality pool noodle that doesn't absorb any water. The density of the closed cell sponge materials are so high that no coating on the closed cell foam is required to be non-porous and durable. 


These types of positioning sponges are 100% radiolucent and will not show up under x-ray. These radiolucent sponges come in a charcoal grey color and will stay artifact-free even with normal wear and tear. Field of view is not a concern due to the properties of the radiolucent xray positioning sponge. 

Stealth Sponges VS Non-Stealth Sponges

The terms "Stealth-Core" or "Stealth-Coat" are trademarks of Techno-Aide for a specific style of sponge design. Techno-Aide developed and patented a way to make nearly any sponge design artifact-free by applying proprietary angles to the design of the sponge. We take a design like a square and "flare" the sides to a patented angle to greatly reduce artifacts. (For more on artifacts, refer to this Guide to X-Ray Positioning Sponges and Aids.)


It is important to note, proper application of any sponge will determine the chance for artifacts. Sponges are typically designed for specific procedures and failure to adhere to these purposes will typically result in artifacts and unacceptable images. 

Stealth Core VS Stealth Coat 

Stealth-Core - A typical sponge is considered "core foam" (where the "core" in Stealth-Core comes from). A Stealth-Core sponge is a non-coated piece of sponge that we have applied patented angles to the design to eliminate artifacts. 


Stealth-Coat - We take a coated sponge design and apply our patented angles to it. This ensures that the sponge is artifact-free. As mentioned before, if coating is applied to a sponge it will show under imaging. However, a sponge can show and not be considered an artifact, as I described before. Our design ensures the sponge does not show artifacts. 


Traditional sponges are not our Stealth cut sponges. These sponges have the same medical-grade coating applied as our Stealth Cote Coated sponges, but do not have angles applied to them, leaving a smaller footprint. Because the angles are not applied, we cannot document that they are artifact-free. Our Stealth line of sponges has a unique angle applied to the sponge edges so that when coated with our proprietary mixed medical grade coating, the chance of artifacts is greatly reduced.

Frequently Asked Questions About X-Ray Positioning Sponges 

What is a closed cell sponge?

Closed cell sponges are made of a particular type of foam where the cell is completely enclosed by its walls and does not connect with others. Closed Cell Sponges are made from a lightweight, radiolucent, non-porous foam that is often made by subjecting a closed cell sponge rubber compound to a gas, such as nitrogen, under high pressure. These radiolucent sponges are made of materials that have fluid and oil resistance, are easy to clean and are extremely durable.

What is a non-coated sponge?

Non-Coated Sponges are a basic (core), open-cell piece of foam. These sponges do not feature a cleanable surface and are not resistant to fluid absorption. This type of positioning sponge can be stealth or non-stealth. 

What is a coated sponge? 

Coated Sponges are fluid-resistant, and have a cleanable coating covering the foam interior. This type of positioning sponge can also be stealth or non-stealth. 

What is a non-stealth sponge?

Non-Stealth Sponges are formed with traditional angles and do not feature proprietary "flared" angles to offer significantly reduced artifacts during viewing. Non-stealth (or non-flared) sides may show artifacts when imaging, specifically when a coating is applied

What is a stealth sponge?

Stealth Sponges are designed with proprietary "flared" angles to offer significantly reduced artifacts during viewing. Flared sides will increase the overall size.


If you want to know more about x-ray positioning sponges, take a look at this Guide to X-Ray Positioning Sponges and Aids. For any questions about any of Techno-Aide sponge products or positioning aids, contact us today.