StemRad Files IPO Prospectus Highlighting Lead-Free, Selective Radiation Protection Solutions for Interventional Radiology and Beyond

In today’s world, where electronic and electrical products are increasingly ubiquitous, the health hazards posed by radiation are extensive and difficult to predict. Exposure to high doses of radiation can cause bone marrow damage that may lead to death, while long-term exposure to low doses of radiation may increase the risk of cancer. In daily life, many people place undue faith in various unproven methods claimed to block or reduce radiation. In contrast, within the high-tech sector, a scientifically validated protective measure has long been available: radiation-protective clothing.

Radiation Protective ClothingRadiation protective clothing is a specialized garment designed to minimize the biological effects of radiation by shielding against ionizing rays. Currently, it is widely used in sectors with significant radiation exposure, including healthcare, chemical engineering, national defense, and construction. In clinical practice, interventional physicians are required to wear radiation protective clothing to prevent radiation-induced injuries. In accordance with national regulations, patients must also be provided with radiation protective gear during examinations to shield non-targeted areas, particularly the gonads and thyroid gland.

According to surveys, the research and development of low- to mid-end radiation protective clothing in China is developing steadily, but the development of high-end radiation protective clothing is slow, with 99% of high-end products relying on imports. In addition, 40% of the main raw material lead for radiation protective clothing relies on imports, and since 2020, the lead raw material market has experienced a tight supply situation. Lead-free materials mainly rely on imports and are expensive.

In a field with widespread demand, why have overseas markets managed to secure the high ground? Where exactly do the R&D barriers for high-end radiation protective clothing lie, and how can they be overcome?

Stemrad is a personal protective equipment company founded in 2011, headquartered in Tel Aviv, Israel, with an office in Florida.

Stemrad was founded by Daniel Levitt, a serial entrepreneur with over 23 years of executive experience. He has served as CEO or co-founder of six high-tech and life sciences companies, and as an advisor to 14 companies.

Traditional radiation protective garments suffer from two primary drawbacks: excessive weight and poor mobility. Conventional full-body protective suits available on the market weigh approximately 7.5–10 kg, making it difficult for workers in any profession to perform long-term tasks while wearing such heavy gear. To address these issues, StemRad pioneered a SELECTIVE RADIATION PROTECTION approach.Selective shielding does not require whole-body protection; instead, it protects vulnerable areas such as the abdomen and regions rich in hematopoietic stem cells, leveraging the regenerative capacity of these stem cells to facilitate bodily recovery.The OECD report notes that partial body shielding, which is lightweight and selectively employs substantial shielding materials to protect bone marrow and preserve its hematopoietic function, may prevent the acute health effects of gamma radiation on the human body.

Currently, based on the concept of selective shielding, StemRad has developed three categories of products for different scenarios.

StemRad 360 Gamma is StemRad, Inc.’s inaugural product and its most widely deployed solution. Among comparable radiation protective garments, it offers the greatest assurance of bodily mobility. The StemRad 360 Gamma is currently utilized in military, nuclear reactor industry, emergency response, and civilian sectors.

StemRad 360 Gamma has been validated through multiple experiments involving firefighters and astronauts, confirming that its materials are 100% flame-retardant. Its ergonomic design allows for easy wear over various types of clothing, effectively mitigating radiation threats. In high-radiation environments, gamma rays produced by the decay of Cs-137 pose significant harm to the human body. Testing has demonstrated that the StemRad 360 Gamma can also effectively protect against gamma radiation.

The other two products are StemRad MD, designed for the medical field, and AstroRad, manufactured for deep-space aerospace missions.

For a long time, interventional physicians have been plagued by radiation exposure, leading to conditions such as neck, spinal, hip, and knee joint injuries. Most products on the market are designed based on the concept of full-body shielding. This approach presents a dilemma: opting for full-body protective garments imposes significant weight that restricts mobility during surgery, potentially compromising procedural precision; conversely, choosing standard lead aprons for greater maneuverability exposes physicians to radiation hazards. Traditional radiation protective clothing either offers adequate protection but hinders easy movement, or allows for ease of movement but provides insufficient protection.

To resolve this contradiction, STEMRad MD has made significant efforts. First,Combining ergonomic exoskeleton design, the exoskeleton helps doctors bear the full weight of protective suits while allowing flexion of the hip and knee joints, enabling rapid walking for agile operations.Exoskeleton designs were first applied in the field of rehabilitation medicine, providing effective assistance to patients when worn.

To provide comprehensive protection for physicians, the STEMRad MD is also equipped with a protective face shield that blocks low-angle scattered radiation without obstructing the line of sight or interfering with surgical procedures. Compared to leaded glasses, it shields a larger area, enhancing protection for the face, head, eyes, and brain. The protective face shield is supported by the exoskeleton system, allowing physicians to wear their own prescription glasses simultaneously.

STEMRad MD also adoptsLead-free materialsManufactured using lead-free materials that offer radiation protection equivalent to lead, these products are made from environmentally friendly materials such as rare earth elements. They are softer and more eco-friendly than lead, effectively reducing the weight of protective garments and preventing the release of lead dust due to lead degradation, thereby avoiding respiratory tract contamination.

Generally, radiation protective garments use lead as the raw material. In China, there are detailed regulations specifying the lead equivalence for various parts of these garments, and their service life is stipulated to be 4–5 years. However, 40% of China’s lead raw materials rely on imports. Since 2020, import-related constraints have led to a tight supply situation in the lead raw material market. High material consumption and expensive raw materials have driven up production costs, and these elevated costs have dampened momentum in the domestic radiation protective garment market. Nevertheless, the situation is changing. Statistics show that, driven by the continuous growth in output of the major downstream product—lead-acid batteries—China’s lead production has been steadily increasing in recent years. By 2021, China’s lead concentrate production reached 1.554 million metric tons, representing a year-on-year increase of 16.9% compared with 2020.

If lead-free materials are adopted, the primary challenge is also the scarcity of raw materials. Currently, the lead-free materials used in China mainly rely on imports and are expensive. To address the shortage of raw material production, technical issues must be resolved first. Scientific research and innovation in China are conducting studies on lead-free materials and have already made significant progress. In August 2022, a research team from Sichuan University announced that they had solved two major technical challenges in the research on lead-free piezoelectric materials. It is believed that with technological development and continuous capacity expansion, the two major obstacles—technical barriers and raw material barriers—can be overcome.

According to surveys, China has a total of 8,716 interventional physicians, 3,511 interventional technologists, and 10,895 interventional nurses. Although the number of interventional physicians in China is only one-fifth that of the United States, interventional medicine has effectively become the third major medical discipline, alongside internal medicine and surgery. In the future, with the continuous development of interventional medicine, there will be a growing demand for more specialized interventional physicians. Currently, over 60% of hospitals in China have established interventional departments dedicated to the popularization and application of interventional medicine.

AstroRad is a radiation protection garment specifically designed for astronauts operating beyond low Earth orbit (LEO). It effectively reduces the risk of exposure-induced death (REID) and eliminates the possibility of acute radiation syndrome (ARS) caused by solar particle events (SPEs).

AstroRad was jointly developed by StemRad and Lockheed Martin based on the StemRad 360 Gamma. AstroRad is composed of hydrogen-rich polymers; hydrogen is one of the most abundant elements in the universe, and this polymer facilitates shielding against space radiation while minimizing the generation of secondary radiation. Currently, StemRad is exploring the use of regenerative materials from spacecraft to fabricate protective garment components, thereby reducing the payload mass of spacecraft.

Testing has confirmed that AstroRad complies with the ALARA principle of radiation protection and can continue to be used within spacecraft shelters. Crew members can combine sheltering with AstroRad wearables to minimize radiation risk.

In 2018, NASA and the Israel Space Agency (ISA) signed an agreement at a space symposium held in Colorado Springs to launch StemRad’s AstroRad radiation protection vest on NASA’s Artemis I lunar mission, which was the final uncrewed test flight before NASA resumed human spaceflight missions for the first time since 1972.

Apart from the Apollo lunar missions, human space exploration has been confined to low Earth orbit. This is because Earth’s magnetosphere shields against most radiation hazards, including solar storms and galactic cosmic rays from deeper space. However, during longer-duration, deep-space crewed missions, astronauts become significantly more vulnerable to radiation exposure, which represents one of the most critical challenges for NASA in launching crewed missions to Mars. Consequently, AstroRad has become an integral component of NASA’s space exploration program.

Since 2019, AstroRad has been utilized on the International Space Station for advanced human ergonomics research in microgravity. In September 2022, NASA launched AstroRad to the International Space Station as part of the Artemis mission to conduct the “Matroshka AstroRad Radiation Experiment,” evaluating the efficacy of AstroRad’s radiation protection. The mission, which is expected to include lunar landing and return phases, will last for one and a half months.