First Human Cell Experiments With FLASH Carbon Ions.

Authors :: Tashiro M
Yoshida Y
Oike T
Nakao M
Yusa K
Hirota Y
Ohno T
Source :: Anticancer research [Anticancer Res] 2022 May; Vol. 42 (5), pp. 2469-2477.
Publication Year :: 2022
Abstract: Background/aim: This study aimed to establish a setup for ultra-high-dose-rate (FLASH) carbon-ion irradiation, and to conduct the first human cell experiments using FLASH carbon ions.<br />Materials and Methods: A system for FLASH carbon-ion irradiation (1-3 Gy at 13 or 50 keV/μm) was developed. The growth and senescence of HFL1 lung fibroblasts were assessed by crystal violet staining assays and senescence-associated β-galactosidase staining, respectively. Survival of HSGc-C5 cancer cells was assessed by clonogenic assays.<br />Results: The dose rates of carbon ions ranged from 96-195 Gy/s, meeting the definition of FLASH. With both 13 and 50 keV/μm beams, no FLASH sparing effect was observed on the growth suppression and senescence of HFL1 cells, nor on the survival of HSGc-C5 cells.<br />Conclusion: We successfully conducted the first human cell experiments with FLASH carbon ions. No FLASH effect was observed under the conditions examined.<br /> (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)