Crister Ceberg
Professor
The FLASH effect depends on oxygen concentration
Författare
Summary, in English
OBJECTIVE: Recent in vivo results have shown prominent tissue sparing effect of radiotherapy with ultra-high dose rates (FLASH) compared to conventional dose rates (CONV). Oxygen depletion has been proposed as the underlying mechanism, but in vitro data to support this have been lacking. The aim of the current study was to compare FLASH to CONV irradiation under different oxygen concentrations in vitro. METHODS: Prostate cancer cells were irradiated at different oxygen concentrations (relative partial pressure ranging between 1.6 and 20%) with a 10 MeV electron beam at a dose rate of either 600 Gy/s (FLASH) or 14 Gy/min (CONV), using a modified clinical linear accelerator. We evaluated the surviving fraction of cells using clonogenic assays after irradiation with doses ranging from 0 to 25 Gy. RESULTS: Under normoxic conditions, no differences between FLASH and CONV irradiation were found. For hypoxic cells (1.6%), the radiation response was similar up to a dose of about 5-10 Gy, above which increased survival was shown for FLASH compared to CONV irradiation. The increased survival was shown to be significant at 18 Gy, and the effect was shown to depend on oxygen concentration. CONCLUSION: The in vitro FLASH effect depends on oxygen concentration. Further studies to characterize and optimize the use of FLASH in order to widen the therapeutic window are indicated. ADVANCES IN KNOWLEDGE: This paper shows in vitro evidence for the role of oxygen concentration underlying the difference between FLASH and CONV irradiation.
Avdelning/ar
- Tumörmikromiljö
- Radiotherapy Physics
- BioCARE: Biomarkers in Cancer Medicine improving Health Care, Education and Innovation
Publiceringsår
2019-12-20
Språk
Engelska
Publikation/Tidskrift/Serie
British Journal of Radiology
Volym
93
Issue
1106
Dokumenttyp
Artikel i tidskrift
Förlag
British Institute of Radiology
Ämne
- Biomedical Laboratory Science/Technology
- Other Physics Topics
Status
Published
Forskningsgrupp
- Radiotherapy Physics
ISBN/ISSN/Övrigt
- ISSN: 1748-880X