Author Of 1 Presentation
BIOLOGICAL EFFECT OF MURINE VENTRAL SKIN IRRADIATION WITH PULSED FLASH RADIOTHERAPY USING A CLINICAL LINAC
Abstract
Background and Aims
To investigate the biological effect of murine ventral skin irradiation with FLASH radiotherapy compared with conventional irradiation.
Methods
Female FvB mice were randomly assigned to three groups: control, conventional (CONV) and FLASH groups. Mice were irradiated at 9 to 19 Gy of CONV (0.1 Gy/s) or FLASH (38.5-600 Gy/s) irradiation using traditional and modified Elekta Synergy linac (6 MeV), respectively. Doses were verified by Gafchromic films positioned under the body. Body weights were recorded every week 1 to 6 weeks after irradiation. Enzyme linked immunosorbent assay (ELISA) were performed in skin tissue lysis and serum samples of the mice for four inflammatory cytokines: tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-6 (IL-6) and IL-10. Flow cytometry using antibodies for CD3, CD8, CD4 and CD45 in blood were performed pre- and 1-week post irradiation.
Results
A significant increase in weight percentages relative to pre-irradiation were observed in the FLASH group, and the alteration of serum and skin tissue levels of TNF-α, IFN-γ, IL-6 and IL-10 induced by FLASH was mild compared with that of CONV. The CD8+/CD45+ ratio in the blood were higher in the CONV than in FLASH and pre-irradiated ratio. These data indicate that lower inflammatory cytokine levels of serum and skin tissue in FLASH could be the result of minor immune overactivation.
Conclusions
Ultra-high dose rate electron FLASH caused less body weight loss, minor inflammatory cytokine levels of serum and skin tissue, as well as less CD8+/CD45+ ratio in the blood. Thus, electron FLASH irradiation represents a new approach of radiotherapy.