First Korean FLASH Radiation Study Published in International Journal...Dongnam Institute of Radiological & Medical Sciences Draws Attention

Protective Effects on the Immune System Demonstrated in Animal Studies

Potential of Next-Generation Cancer Therapy Technology Highlighted

The research team led by Chief Indu Sol of the Department of Radiation Oncology at Dongnam Institute of Radiological & Medical Sciences (Director: Jung Seung-pil) has published a paper on FLASH radiation preclinical animal studies in the February 2026 issue of the international journal Radiation Research, a leading publication in the field of radiation research. This is the first time that FLASH radiation research conducted directly in Korea has been published in an international journal.

The paper is titled "Effects of Ultra-High Dose-Rate Radiotherapy (FLASH-RT) on the Hematopoietic and Immune Systems: An Animal Study," and analyzes, through animal experiments, the effects of ultra-high dose-rate radiotherapy on the hematopoietic and immune systems.

FLASH radiotherapy is a next-generation radiation therapy technology that delivers an ultra-high dose rate of over 40 Gy per second in less than 0.1 seconds. It is characterized by utilizing a dose rate thousands of times higher than conventional radiotherapy. Since 2014, when a French research team demonstrated the so-called "FLASH effect"—significantly reducing normal tissue damage in animal experiments—global research in this area has accelerated.

This study is particularly meaningful as it has identified the protective effects on the immune system. The research team observed the spleens of experimental animals after administering FLASH radiotherapy and confirmed that the recovery rate from lymphopenia was faster than in the conventional radiotherapy group. This proves at the animal level that the spleen, a key organ responsible for the production and storage of immune cells, is better protected in a FLASH radiation environment.

These results are evaluated as showing the potential to both reduce the immune suppression that occurs during radiation therapy and enhance treatment efficacy. Previous international studies have also reported that FLASH radiotherapy maintains tumor-suppressing effects while reducing normal tissue damage, such as pulmonary fibrosis.

In 2020, Dongnam Institute of Radiological & Medical Sciences established DARF (DIRAMS Accelerator Research Facility), an interdisciplinary research consortium consisting of experts in radiation oncology, radiation physics, and radiation biology, and launched Korea’s first FLASH radiation preclinical animal experiments.

The research team first presented these findings at the 2022 annual meeting of the Radiation Research Society (RRS), then supplemented the data and submitted the paper to the journal in September 2023. After a rigorous review process, the study has now been officially published.

Indu Sol, Head of Strategic Research and Development (first author), commented, "Our finding that FLASH radiotherapy better preserves the immune system demonstrates its potential to address two major challenges in cancer treatment simultaneously. It can reduce side effects while protecting human immunity, thereby improving therapeutic outcomes, and a significant synergy can be expected especially when combined with immune checkpoint inhibitors."

Corresponding author Jeon Wan, Chief of the Department of Radiation Oncology, stated, "This achievement is the result of collaboration among experts in medicine, physics, and biology. We will focus our efforts on expanding preclinical studies to accelerate the clinical application of FLASH radiotherapy."