Lightweight polymer protects X-ray workers from chronic pain and lead toxicity

A light, flexible polymer material developed at the University of Waterloo could replace the lead in heavy X-ray aprons, providing the same protection from harmful radiation while reducing their weight by almost 90 per cent.

For patients who only get X-rays once in a while, heavy lead aprons might be okay, but technicians who wear them every day often develop back and neck pain. Some of them have to retire early as a result."

Dr. Tizazu Mekonnen,  Professor, Chemical Engineering, University of Waterloo

Most aprons used for long periods of time also shed lead dust that can be inhaled or ingested by workers. Lead affects many areas of the body, including the cardiovascular and neurological systems and no amount of exposure is considered safe by the World Health Organization.

"Our research shows that radiation shielding does not have to rely on toxic, heavy materials such as lead," Mekonnen said. "By engineering the size, shape, arrangement and distribution of nanoparticles within flexible polymers, we can achieve excellent X-ray protection while dramatically reducing weight. This opens the door to safer, more comfortable shielding materials for health-care workers and others who are routinely exposed to radiation."

Researchers experimented with several alternatives to lead – including bismuth, gadolinium, barium and other heavy metals - before focusing on tungsten, which is well-suited to blocking X-rays because of its high density at the atomic level.

After first processing tungsten into tiny nanoparticles, they mixed them into a soft, silicone-based plastic to form nanocomposite sheets.

To prevent the nanoparticles from making the new material too stiff, they arranged them in layers called gradients. They also determined rod-shaped nanoparticles work best to block X-rays, a necessary tool in medicine, industrial inspection, security screening and military applications.

Tests and modelling with the flexible, lightweight polymer material for X-ray aprons were conducted at Grand River Hospital in Kitchener with Dr. Ernest Osei. 

PhD student Aklilu G. Messele, who co-authored a paper on the research, is now exploring its use for other types of radiation, including gamma ray emissions in the nuclear energy sector and to block electromagnetic waves from devices such as cellphones and Wi-Fi.

"We carry cellphones every day," said Mekonnen, a Canada Research Chair in Sustainable Multiphase Polymers. "The impact on our bodies is unknown. What if we can design a cover that protects from the radiation emitted by our phones?"