Mechanistic Understanding of FLASH Radiotherapy:
Bridging Radiation Physics, Radiation Chemistry and Radiobiology

Position

Employer: THERYQ (ALCEN Group)

Permanent contract (CDI)

Location: Inserm U1355 Molecular Radiotherapy and Therapeutic Innovations, Gustave Roussy, Villejuif, France

Scientific Background

FLASH radiotherapy has emerged as one of the most promising innovations in radiation oncology. While its ability to reduce normal tissue toxicity has been demonstrated in numerous preclinical studies and is now entering clinical evaluation, the physicochemical and biological mechanisms underlying the FLASH effect remain largely unresolved.

Building upon ongoing work on water radiolysis and reactive oxygen species production under ultra-high dose-rate irradiation, this project aims to establish a multidisciplinary research programme combining radiation physics, radiation chemistry, computational modelling and radiobiology to investigate the mechanisms of FLASH radiotherapy. Particular emphasis will be placed on extending current models beyond aqueous systems towards biologically relevant media and cellular environments.

Scientific Environment

The successful candidate will join Inserm U1355 at Gustave Roussy, a multidisciplinary unit bringing together approximately 50 researchers, clinicians and engineers with expertise in:

• Radiation oncology
• Medical physics
• Accelerator physics
• Radiobiology
• Pharmacy
• Data science
• Translational research

Scientific supervision: Charlotte Robert, Eric Deutsch and Gérard Baldacchino.

Collaborations include Gustave Roussy (U1355, radiotherapy departement), THERYQ and CEA-IRAMIS/LIDYL (Dr Gérard Baldacchino).

Research Objectives

• Develop an integrated mechanistic framework linking energy deposition, radiation chemistry, reactive species production, biologically relevant media and cellular response.
• Combine computational modelling with experimental validation across multiple spatial and temporal scales.
• Improve the mechanistic understanding of the FLASH effect.

Main Responsibilities

• Establish Geant4-DNA capabilities within the laboratory.
• Develop mechanistic models of FLASH irradiation.
• Investigate radiation chemistry in aqueous and biologically relevant media.
• Participate in FLASHKNiFE irradiation campaigns.
• Perform irradiations of chemical solutions and cell culture media.
• Compare simulations with physicochemical and radiobiological measurements.
• Contribute to advanced FLASH dosimetry.
• Develop AI-assisted literature mining workflows with ASNR.
• Maintain scientific watch and disseminate results through publications and conferences.

Experimental Resources

• FLASHKNiFE irradiation platform
• Detectors (FLASHDiamond, Radiochromic films, Fricke chemical dosimetry, Alanine dosimetry (CEA-LNHB))
• Irradiation facilities for chemical solutions and cell culture media
• Radiobiology platforms at Gustave Roussy

Candidate Profile

Applicants should hold a PhD in Physics, Medical Physics, Physical Chemistry, Radiation Chemistry or a related discipline.

• Experience in radiation chemistry, Monte Carlo simulations, Geant4/Geant4-DNA, dosimetry, computational modelling and/or Python programming is desirable.
• Scientific curiosity, autonomy and strong interest in interdisciplinary research.

Scientific Opportunities

• Contribute to a multidisciplinary FLASH research programme.
• Participate in advanced FLASH irradiation campaigns.
• Collaborate with Université Paris-Saclay (iNanoTheRad), CEA-IRAMIS/LIDYL, CEA-LNHB and ASNR.
• Publish in leading journals and present at ESTRO, FRPT and other international conferences.
• Contribute to the ESTRO FLASH Focus Group.