Radiation shielding – What Makes for an Effective CBRN Radiation Shield?
10.31.18 | Wednesday | Nofit Amir
Professionals who deal with the aftermath of a nuclear or radiological event need personal protection. Any CBRN radiation protection solution can – or should be able to – shield workers from the devastating effects of gamma radiation. But like with so many other things, how you approach protection is key. Many of the solutions touted for protection are inefficient, heavy – and ineffective in blocking radiation associated with nuclear or radiation incidents, as they do not provide adequate protection to the most vulnerable parts of the body. With our solution – the 360 Gamma radiation shield – personnel are equipped with smart shielding that provides focused protection from gamma radiation for the most sensitive parts of the body.
The problem with CBRN radiation shielding solutions
There are numerous approaches to gamma radiation protection, most of them based on spreading as thick a layer as possible of materials like composite metals, lead, or specialty fabrics over the body. To reduce typical gamma rays by a factor of a billion, according to the American Nuclear Society, thicknesses of shield need to be about 13.8 feet of water, about 6.6 feet of concrete, or about 1.3 feet of lead. Thick, dense shielding is necessary to protect against gamma rays.
To protect the body against gamma rays, many of the CBRN radiation shield solutions on the market pack on the protection – to the extent that even moving in the outfits is difficult, if not impossible. At Chernobyl, for example, some of the responders tried to protect their entire bodies with thin sheets of lead similar to what is worn in hospitals to protect against low-energy x-rays (and insufficient for high-energy gamma rays). But even with 26 kilos of this material on their bodies – heavily encumbering them – their most sensitive and vulnerable body parts remained inadequately protected, and many of them died from the hematopoietic sub-syndrome of acute radiation syndrome which arises from the destruction of the bone marrow tissue.
Advanced materials for CBRN radiation shielding, not a solution either
Even when materials that are touted as being more effective than lead are used, lugging around heavy whole-body protective suits considerably slow down the wearer and creates unnecessary heat-stress. The average male human body has a surface area of 19000 cm2 and the torso is approximately 36% of that surface area, which means a vest made out of material that has a density of 3.14 g/cm3 with an attenuation factor of 2 would weigh 58 kg. This is an unrealistic weight for someone to carry – and as the products on the market that use these materials are considerably lighter (that is among their selling points), they provide much less protection than would be required.
Even if you were to provide someone with a 58 kg vest providing 2 fold protection and they were able to wear it, the dose received is proportional to the time of exposure and by virtue of carrying an additional 58 kg one would be slowed considerably, thereby negating the benefits of their shielding or even being counter-productive and worsening their absorbed dose.
Why StemRad’s CBRN radiation shielding solution is better
If heavy protective outfits cannot provide adequate protection while allowing freedom of movement for those wearing them, StemRad solves the problem with its innovative approach. StemRad’s 360 Gamma provides significant shielding arranged in the most efficient configuration to provide focused protection to the most sensitive area in the body- the pelvis, where we have 50% of the body’s bone marrow and other sensitive organs. This offers efficient protection against high energy gamma radiation which military and civilian first responders would encounter during a nuclear or radiological event.
The need for robust protection for bone marrow tissue is simply understood just by looking at the numbers; Nuclear first responders are not working with x-ray machines which emit radiation at low energies (about 10 times lower), but with high energy gamma emitters like Cs-137 (662 keV). As the energy of radiation increases, so does its ability to penetrate through shielding – thus the need for thicker shielding at critical areas.
But as we have seen, thick shielding throughout is impractical – and often ineffective. The StemRad approach of selectively shielding critical bone marrow tissue with robust shielding is the best way to protect humans from gamma radiation. When detection systems indicate they are required, the best approach is a CBRN gamma radiation shield which can be a modular add-on to standard thin HAZMAT suits, preventing internal contamination of radioactive or other materials. This efficient approach allows first responders to operate efficiently without undue weight burden with solution that is fully compatible with their existing PPE. The StemRad 360 Gamma offers the greatest biological protection without compromising mobility by providing significant focused, selective, shielding where it matters most.