Siemens Healthineers wins ARPA-H funding for Flash therapy

Siemens Healthineers’ Varian business has received an ARPA-H award of up to $60M over 5 years to advance photon Flash radiotherapy for cancer care.

The U.S. Advanced Research Projects Agency for Health is funding the project to develop photon Flash therapy on traditional linear accelerators. Siemens Healthineers will add $23M as a cost share, bringing the total project commitment to up to $83M, according to the company.

Flash therapy is an experimental radiotherapy approach that delivers radiation at ultra-high dose rates. Siemens Healthineers said photon Flash therapy can deliver treatment more than 100 times faster than current technologies, with the goal of reducing damage to surrounding healthy tissue while maintaining tumor control.

The project focuses on photon beams rather than proton or electron beam systems. That distinction matters because conventional C-arm linear accelerators are widely installed in radiation oncology departments, potentially giving photon Flash therapy a broader route to clinical adoption if the technology proves safe and effective.

ARPA-H’s project page describes radiation therapy as a core cancer treatment that often requires 10 to 30 daily low-dose sessions. The agency said Flash radiotherapy relies on a biomedical phenomenon in which ultra-high dose rates are toxic to tumor cells while sparing healthy tissue.

“This investment from ARPA-H strengthens our efforts to explore the potential of photon flash therapy,” said Arthur Kaindl, head of Varian at Siemens Healthineers.

Varian’s role gives the project a direct link to existing radiation oncology infrastructure. Siemens Healthineers said the work will build on the installed base of C-arm linear accelerators, aiming to speed potential adoption and broaden access if clinical development is successful.

The American Society for Radiation Oncology also welcomed the funding. Sameer R. Keole, MD, chair of ASTRO’s board of directors, said the award marks a milestone for the field and supports research into advanced radiation therapy technologies.

The technology remains investigational. Siemens Healthineers noted that Flash therapy is not yet cleared for routine clinical use, and further development will be needed to evaluate safety, treatment planning, delivery, and clinical outcomes.

If successful, photon Flash therapy could address 2 major pressures in cancer care: reducing normal-tissue toxicity and shortening treatment delivery. The potential operational impact is also significant, since faster delivery could improve patient throughput and reduce treatment burden.

The 5-year ARPA-H project will test whether photon Flash can be developed on a platform that is more accessible than specialized proton or electron systems. That makes the award important not only as a funding announcement, but as a bet on whether Flash radiotherapy can move from experimental promise toward scalable cancer care.