First Human Cell Experiments With FLASH Carbon Ions
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Published on: October 29, 2011
Mutsumi Tashiro1, Yukari Yoshida2, Takahiro Oike2,3
1Gunma University Heavy Ion Medical Center, Gunma, Japan; tashiro@gunma-u.ac.jp.
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.
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.
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.
Conclusion:
We successfully conducted the first human cell experiments with FLASH carbon ions. No FLASH effect was observed under the conditions examined.
