Custom compounder RTP Company, Winona, MN, has announced the availability of specialty thermoplastic compounds capable of absorbing radiation. Called Radiopaque Compounds, they can be formulated to be visible under x-ray imaging or as a shield to protect people from x-ray generating sources.
When used to produce medical devices for insertion into the body for diagnostic or surgical procedures, the additives in Radiopaque Compounds render the devices visible under fluoroscopy or x-ray imaging. The additives, or radiopacifiers, attenuate energy differently than surrounding bodily tissues, providing the contrast in a x-ray image. The type and amounts of radiopaque additives used will affect the image contrast and sharpness.
Because they can resist x-ray penetration, Radiopaque Compounds are also used to produce shielding components to enclose radiation generating sources. Since the impermeability of a shielding material is proportionate to its density, lead has historically been used, but not without health and environmental concerns. In contrast, Radiopaque Compounds possess the desirable attributes of lead without the toxicity and disposal issues. They offer similar radiation-shielding properties, ease of forming, and comparable density.
The Radiopaque Compounds can be formulated using a variety of thermoplastic polymers and additives to customize a product’s specific gravity and physical properties (such as flexural modulus, tensile strength, and impact strength) for specific end-use requirements. The type and amount of additives depends on the base resin and on the wall-thickness, surface smoothness, color and other desired properties of the application. Among the most widely used radiopacifiers are barium sulfate, bismuth, and tungsten. Radiopaque Compounds can be processed using conventional injection molding and extrusion techniques.