Innovative application of UHMWPE boron-containing sheet in CT room protective door produced by BEYOND

Innovative application of UHMWPE boron-containing sheet in CT room protective door produced by BEYOND

Material properties and radiation protection mechanism

The ultra-high molecular weight polyethylene (UHMWPE) boron-containing sheet produced by BEYOND is a composite protective material with ultra-high molecular weight polyethylene as the base material and added with boron compounds (such as boron carbide and boric acid). Its molecular weight is as high as 1.5 million or more, forming a dense three-dimensional network structure, giving the material extremely high impact resistance and energy absorption capacity. By adding boron elements (usually 5%-10%), the absorption efficiency of the board to neutron radiation is significantly improved. Boron has a thermal neutron absorption cross-section of up to 3837 barns, which can effectively capture neutrons and convert them into harmless alpha particles; at the same time, the hydrogen element in the polyethylene base material slows down fast neutrons through elastic collisions, forming a "slowing-absorption" dual protection mechanism.

In view of the X-ray-dominated radiation environment in the CT room, BEYOND further optimized the material formula and developed the lead-boron polyethylene composite board. The material adopts a multi-layer structure design: the outer layer is stainless steel or corrosion-resistant coating, the middle layer is UHMWPE-boron composite layer (neutron shielding), and the inner layer is embedded with lead foil (X/γ-ray shielding) to achieve full-spectrum radiation protection. This design reduces the weight of traditional lead doors by 30%, while meeting the leakage radiation limit (≤2.5μSv/h) of the "Medical X-ray Diagnostic Radiation Protection Requirements" (GBZ 130-2020).

Core advantages in CT room protection doors

1. Lightweight and high strength

The density of the boron-containing UHMWPE sheet is only 0.94g/cm³, which is 90% lighter than lead (11.34g/cm³), greatly reducing the weight of the door body. Taking the standard CT room protection door (2.5m×2m) as an example, the traditional lead door weighs 800kg, while the boron-containing polyethylene composite door only needs 200-300kg, reducing the load-bearing pressure of the building structure. At the same time, its tensile strength reaches 40MPa, and its impact strength is 8 times that of carbon steel, and it can withstand more than 100,000 opening and closing impacts.

2. Composite protection and environmental protection

Traditional lead plates have the risk of oxidation pollution, while UHMWPE boron-containing sheet achieve environmental protection upgrades through lead-free design (such as using rare earth gadolinium to replace lead). Experiments show that the 15cm thick modified gadolinium oxide/boron carbide/polyethylene composite plate has a shielding rate of 98% for californium-252 neutron source, and a shielding rate of 72% and 60% for cesium-137 and cobalt-60 gamma rays, respectively, and its comprehensive performance is better than that of traditional lead-boron polyethylene.

3. Corrosion resistance and easy maintenance

The surface smoothness of the sheet is Ra≤0.2μm, it does not absorb pollutants, and can be directly wiped and disinfected with medical alcohol. Its water absorption rate is less than 0.01%, and it still maintains dimensional stability in the high humidity environment of the CT room (relative humidity ≥70%), avoiding the problem of deformation and cracking of traditional wood protective doors.

3. Technological breakthroughs

Intelligent integration: The door body is embedded with pressure sensors and infrared anti-pinch devices. When encountering obstacles, it will automatically rebound within 0.1 seconds, and the safety is improved by 5 times.

Noise reduction design: Through the self-lubricating characteristics of UHMWPE, the friction coefficient of the guide rail is reduced to 0.05, and the noise of opening and closing the door is ≤45dB.

Thermal neutron shielding verification: According to the test of the China Institute of Radiation Protection, the board has an absorption rate of 95% for 0.025eV thermal neutrons and a slowing efficiency of 76% for 5MeV fast neutrons.

4. Industry trends and future prospects

With the mandatory requirements of the "Medical Radiation Protection Standard" (2025 Edition) for "lead-free protection", the market share of boron-containing UHMWPE boards is expected to increase from 35% in 2024 to 65% in 2028. BEYOND is developing the following innovative directions:

1. Nano-modification technology: Through surface modification of nano-gadolinium oxide, the gamma-ray shielding rate of 15cm thick boards is increased to 85%.

2. Intelligent response materials: Develop temperature-sensitive boron-containing polyethylene, which automatically changes color to warn when the radiation exceeds the standard.

3. Modular installation: Launch a standardized plug-in protective plate system, shortening the construction period from 7 days to 48 hours.

BEYOND's UHMWPE boron-containing sheet is reshaping the medical radiation protection industry through the deep integration of material science and engineering design, providing a "Chinese solution" for the safety protection of CT rooms around the world.