The Belt That Protects Against Gamma Radiation

Years of science fiction, from The Andromeda Strain to Annihilation, have trained us to accept what seems obvious: When there's a science-based catastrophe, only a full-body hazmat suit will protect you. That's why it might be surprising, almost straight-up suspicious, that life-saving protection from a nuclear disaster could be so minimalist as a band around your waist.

Oren Milstein, co-founder of StemRad, knows just how unintuitive his company's solution looks. "How could it be that a belt going around the pelvis of the user is supposed to protect the whole body? It’s protecting only eleven percent of the body’s surface area!"

The answer, at its core, is not a new one. He learned of it years ago under the tutelage of Yair Reisner, an Israeli scientist who was one of four Western experts the Soviet Union called in to treat the victims of radiation poisoning in the wake of the Chernobyl disaster. Reisner's last ditch treatment—a series of 19 bone marrow transplants—informs the principle of the StemRad waistband that would make such operations unnecessary.

Bone marrow, a semi-solid tissue found within in bones of mammals and birds, is where new blood cells are made. Like the heart or lungs, bone marrow is constantly working, producing some 500 billion blood cells a day in the average human. The permanent disruption of this vital function is what makes radiation poisoning so fatal, but preventing it is simper than it may seem. 

StemRad's 'vests,' which come in professional and civilian flavors, only cover about 11 percent of your body's surface around the pelvic region, but it's a very particular and crucial subsection. "You have fifty percent of your body’s bone marrow there," Milstein explained toPopular Mechanics on the phone. "Even if you lose some of that bone marrow due to radiation, you’re left with a critical volume of bone marrow that’s viable post exposure. The minimal amount is just 2.5 percent.”

That number was verified by Dr. Nelson Chao, a cancer and radiation expert at Duke University not affiliated with StemRad who told Popular Mechanics that StemRad’s 2.5 percent number is “probably correct to save the bone marrow and allow for reconstitution.” That is, with only 2.5 percent of bone marrow protected, the human body can start regenerating the stuff on its own and the stem cells keep coming. Those regrown stem cells eventually enter the body’s bloodstream and the body keeps living.

“Working with the lab in animal models of radiation injury,” he says of his time at Weizman, "I could actually see that it was enough to protect just a very small, minute fraction of the bone marrow a mouse to prevent acute radiation syndrome.” Milstein’s lab experimented with two groups of mice, one with minimal bone marrow shielding in the form of lead placed around bone marrow-heavy parts of the body, and one with not.

The mice exposed to radiation without bone shielding, predictably, died within weeks. But the mice with minimal lead shielding survived for as long as years after exposure. Further research showed that what applied to mice would also apply to humans. Then, in 2011, Fukushima happened and Milstein was convinced to abandon academia and pursue what has become StemRad.

Like Chernobyl, Fukushima earned an IAEA ranking of 7, the highest level of nuclear incident possible. But where Chernobyl was a disaster years in the making, caused by poor design and worse safety standards, Fukushima’s meltdown was due to a tsunami’s unexpected strength.

While there were no direct deaths due to the Fukushima Daiichi’s meltdown, but that’s not where nuclear disasters end. Japanese firefighters, for instance, made the courageous decision to fight fires at the radioactive plant for 13 and a half hours straight, with 30-minute rotations. For safety, they donned thin, full-body radiation suits under their heavy gear to reduce the deadly risk of a potential tear. While they had radioactive protection, Milstein says argues that StemRad vests would have been safer and allowed them to enter the plant more confident in their ultimate survival.

Milstein hopes that StemRad's technology won't just serve to protect first responders here on Earth, but could also help astronauts headed into deep space survive the dangerous radiation outside of the warm embrace of the Earth’s magnetic field. An alternate version of StemRad's belt—a larger vest-shaped, custom-fit model called the AstroRad—will go up on an upcoming Orion spacecraft launch for testing in partnership with the German Aerospace Center.

But in space or on Earth, a StemRad vest cannot guarantee protect from every negative affect from radiation, specifically cancer developing in the long term. Radiation exposure increases cancer chances down the road, at least five years after exposure. “While StemRad focuses on preventing acute death,” Milstein says, describing the type of sickness that can kill people in 4-6 days, “it’s also diminishing the likelihood of the cancer due to protection of the bone marrow and other vital organs in the lower abdominal area.

“At the same time,” Milstein cautions, “any exposure to radiation is harmful.” It’s that caution that leads to some skepticism. Dr. Chao, for example, declined to endorse StemRad’s claim on its website that if first responders to Chernobyl had been wearing StemRad shields “it is very likely that almost all of them would still be with us today."

“Marrow is only one component that needs to recover,” Dr. Chao says. “That is to say in the setting of higher total body irradiation, there are other organs involved such as the gut and the lungs which would not be saved by bone marrrow alone.” StemRad’s board includes Robert Gale, an expert on bone marrow transplatation who traveled to the Soviet Union to work with victims of Chernobyl.

It’s not a magic bullet. But it could make the jobs of first responders a lot less dangerous.