New Plastic Can Lower X-Ray Radiation Doses

Toray Industries Inc. has developed a radiolucent carbon fiber-reinforced plastic (CFRP) component that can reduce X-ray radiation doses by 8% while keeping image quality equal to or better than that of conventional counterparts. The company plans to explore practical applications for the component in X-ray examination equipment, including breast supports of mammography and cassettes.

In X-ray examinations, X-rays are transmitted through the human body to generate images of internal structures, helping physicians detect diseases at an early stage. However, as these examinations also pose risks of medical exposure, technologies for clear, low-noise diagnostic images without increasing radiation doses are required. In Japan, the Japan Network for Research and Information on Medical Exposure¹ serves as a hub, collecting data on radiation doses and risk assessments in radiology and publishing diagnostic reference levels² to optimize patient radiation doses.

Detectors in X-ray examination equipment use protective CFRP components because they are lightweight and highly radiolucent. But further improvement in radiolucency is essential to obtain diagnostic images without increasing radiation doses. One effective approach is a low-density sandwich structure comprising CFRP skins and a porous core. However, sandwich structures may cause uneven transmitted X-ray intensity due to density variations in the porous core and component geometry, which could generate noise in diagnostic images. Therefore, achieving both reduction in radiation doses and enhancement in diagnostic precision has been a key challenge.

Toray established an optimized composite design for a sandwich structure incorporating its proprietary carbon fiber-reinforced foam.³ This technology satisfies both low density and high rigidity while suppressing density variations regardless of component geometry. Associate Professor Toru Negishi⁴ of the Department of Radiological Sciences in the Faculty of Health Sciences at Tokyo Metropolitan University evaluated protective components incorporating this sandwich structure under clinical conditions. He confirmed that detective quantum efficiency⁵ was about 6% higher than conventional CFRP. This makes it possible to obtain diagnostic images of equal or greater clarity even with an 8% reduction in X-ray dose. Applied in examination equipment such as breast supports of mammography and cassettes, the component could help improve diagnostic precision while reducing risks of medical exposure.

Under TORAY VISION 2050, the company has committed through its business activities to help build “a world where everyone lives in health and comfort,” and will continue to innovate technologies, guided by its corporate philosophy of “contributing to society through the creation of new value with innovative ideas, technologies and products.”

Toray Industries Inc. considers itself a global leader in advanced materials innovation. It is comprised of more than 300 affiliated companies and approximately 46,000 employees worldwide. Since 1926, Toray has continuously expanded its business portfolio—from Fibers & Textiles, to Resins & Chemicals, Films, Electronics & Information Materials, Carbon Fiber Composite Materials, Pharmaceuticals & Medical Products, as well as Water Treatment & Environment. In April, the company marked the 100th anniversary of its founding.

References
¹ The Japan Network for Research and Information on Medical Exposure was set up in March 2010 to collect and share research information related to medical exposure. It gathers data on facilities, equipment, frequency, radiation doses, and risk assessments in radiology to assess medical exposure levels in Japan. It aims to establish a medical exposure management system in Japan that is on par with those in other developed countries. Website: https://j-rime.qst.go.jp/index.html (Japanese only)
² Diagnostic reference levels are indicators for optimizing patient radiation doses in medical imaging. Website: https://j-rime.qst.go.jp/report/JapanDRLs2025_ja.pdf (Japanese only)
³ Carbon fiber-reinforced foam is Toray’s proprietary porous material whose short carbon fibers form a three-dimensional network bonded by a binder resin. Its structure contains internal voids, making it light but highly rigid.
⁴ Associate Professor Toru Negishi was formerly a director of the Japan Central Organization on Quality Assurance of Breast Cancer Screening (Apr. 2018 – Apr. 2026), as well as a vice-president of the Japanese Society of Radiological Technology (Apr. 2023 – Apr. 2025).
⁵ Detective quantum efficiency shows how efficiently X-rays are used to form images. Thus, the higher radiolucency of protective components, the higher DQE.