The University of Navarra has developed a new personalized method to accurately quantify the radiation dose received by the blood during cancer radiotherapy treatments. It claims that this represents a step forward toward "more personalized, preventative, and safer" oncology medicine.
The research was led by Marina García-Cardosa, a researcher in the Medical Physics and Biophysics (PhysMed) group at the Faculty of Sciences and recognized by international institutions. The study was conducted in collaboration with physicians and researchers from the University of Navarra Cancer Center.
Historically, radiotherapy has focused its efforts on avoiding damage to fixed organs near the tumor, but blood—a mobile and vital tissue that runs throughout the body—has been left out of routine dosimetry calculations. The doctoral thesis defended by Dr. García-Cardosa proposes reversing this omission with an innovative approach: treating blood as an "organ at risk" and adapting treatment to protect it when clinically feasible.
"Each blood cell that passes through a radiation field receives a small amount of energy. Although this dose may seem low, its effect can accumulate over the course of treatment and affect the immune system or cause hematological toxicity," the researcher explains.
A TOOL WITH CLINICAL POTENTIAL
The method, called FLIP-HEDOS, integrates patient-specific anatomical information, real-life blood circulation patterns, and radiation treatment plan data to accurately simulate how and how much blood is irradiated. Thanks to its multidisciplinary approach—combining medical physics, biophysics, oncology, and engineering—this technology enables personalized scenario calculations and assessment of cumulative exposure over long-term treatments.
The results reveal that factors such as the proximity of the tumor to large blood vessels, the type of radiotherapy applied, and the variability of each patient's cardiac output (the amount of blood the heart pumps per minute) directly influence blood irradiation and, consequently, their immune response.
"The immune system is especially sensitive to radiation. Essential cells such as lymphocytes—responsible for coordinating the body's defenses—can be affected even by very low doses. If a significant number of these cells are damaged, the body's ability to respond to infections, inflammation, or even the tumor itself may be compromised. This aspect becomes even more important in treatments that combine radiotherapy with immunotherapy," explains García-Cardosa.
According to the University of Navarra, the participation of the University of Navarra Cancer Center has been essential for integrating clinical experience into advanced cancer treatments. Furthermore, the research has benefited from the guidance of Professor Harald Paganetti, an international expert in medical physics from Massachusetts General Hospital and Harvard Medical School.
INTERNATIONAL RECOGNITION AND FUTURE APPLICATIONS
This work has been recognized as one of the best oral presentations by the European Society for Radiotherapy and Oncology (ESTRO) in Austria (May 2025) and at specialized conferences such as the Radiation Research Society Conference in the United States (September 2024) and by the Spanish Society of Medical Physics at the national level (May 2025). Furthermore, some of its results have been published in the scientific journals 'Radiation Physics and Chemistry', 'Physics in Medicine & Biology', and 'Clinical Cancer Research'.
Regarding its potential for oncological treatments, the authors indicate that the FLIP-HEDOS framework could be useful for simulating drug or radiopharmaceutical distribution, as well as for evaluating new radioprotection and hematological toxicity strategies. "Considering blood as a dynamic organ to be protected represents a paradigm shift in modern radiotherapy. This research not only responds to a scientific need but also to a clinical imperative: to offer safer treatments without compromising oncological efficacy," highlights Professor Javier Burguete, Professor of Medical Physics and Biophysics at the University of Navarra and the thesis supervisor.
CONTRIBUTION TO THE GLOBAL DEBATE ON PERSONALIZED MEDICINE
For the University of Navarra, in an international context where precision medicine and immune system protection occupy a central place on the scientific agenda, this research proposes a technological innovation applied to health with a real impact on patients' quality of life.
Furthermore, he believes this breakthrough raises new questions about how to optimize radiation therapy and its effect on the immune system, adjust session duration, or redesign the direction of radiation beams to minimize blood exposure.
The research has been supported by the Spanish Research Agency—part of the Ministry of Science and Innovation—the Government of Navarra, the la Caixa Foundation, and the Association of Friends of the University of Navarra, among other institutions.
Their results, Burguete points out, "demonstrate that protecting the blood can be important and influence how a patient fares after tumor treatment." As these findings are incorporated into clinical practice, they could mark a turning point in therapeutic planning and the management of side effects in radiation oncology.
