Medical equipment and devices that produce x-rays and gamma rays must be shielded to protect operators, clinicians, patients and sensitive electronic components from tube leakage and room scatter. The European Union's Restriction of Hazardous Substances (RoHS) directive calls for the near-elimination of lead in most electrical and electronic equipment. In addition, lead has design drawbacks. Lead-encapsulated glass plates for protection against x-rays must be very thick, limiting usage and design options. Further, lead shielding can have “hot spots” – areas where x-rays can penetrate. Due to increasing regulation of lead for toxicity and environmental risks, manufacturers are seeking new replacement materials.
A new line of thermoplastic materials with high specific gravity (HSG) has been introduced that could replace lead in many healthcare applications that require radiation shielding. GE's LNP(1) Thermocomp (1) HSG radiation shielding, high-density compounds enable x-ray shielding solutions without the use of known toxic substances, while providing greater design freedom and higher-volume manufacturing with lower total part cost through the use of injection molding. The new material introduced by GE will also offer advantages to manufacturers of radiation-shielding products. It will eliminate the health and disposal challenges posed by lead to manufacturers and will enable them design safer solutions, as well as provide the opportunity for design and cost advantages in a wide range of healthcare applications.
GE's LNP Thermocomp x-ray shielding compounds have been shown to shield radiation up to the effectiveness of lead without leakage or hot spots. They are based on tungsten – a non-hazardous HSG material – in nylon 6. LNP Thermocomp HSG x-ray shielding compounds can be made with enhanced stiffness, strength and impact resistance for demanding injection-molding applications.
With LNP Thermocomp HSG compound, GE Healthcare gained many advantages over lead beyond compliance with environmental regulations. The transition from machined and stamped lead to injection-molded engineering resins may help enable tighter tolerance specifications and greater part consistency, enhancing the performance and safety of the x-ray equipment. Avoiding secondary operations required with lead, plus combining multiple components in one part, reduced total manufacturing time, system cost, and complexity. Part-to-part consistency made possible by injection molding facilitates uniform shielding, and gives designers precise control over the amount of radiation filtered through their devices. This environmentally responsible compound also reduces overall system.
New grades of the Thermocomp HSG material that match the specific gravity of lead, including a flexible version for specialized applications and an elastomeric grade with high elongation that will deliver exceptional design flexibility, are being developed by the company. This composite offers the potential to replace other shielding materials for similar cost and performance advantages. Applications include: x-ray shielding devices and containers, housings, x-ray tubing components, dental x-ray equipment, and nuclear medicine containers.
Future applications for LNP Thermocomp HSG x-ray shielding compounds could benefit from the capabilities of GE's Global Application Technology (GApT) centers, such as user-centric design elements, injection molding application-specific testing, and teardown analysis, which is used to disassemble existing units made of traditional materials such as metals (e.g., lead) and identify part consolidation opportunities attainable with thermoplastic injection-molded parts.