Abstract
Purpose
This study aims to demonstrate, for the first time, the possibility of irradiating biological cells with Gy-scale doses delivered over single bursts of picosecond-scale electron beams, resulting in unprecedented dose rates of 1010 - 1011 Gy/s.
Methods and Materials
Cancer stem cells and human skin fibroblasts were irradiated with MeV-scale electron beams from a laser-driven source. Doses up to 3 Gy per pulse with a high spatial uniformity (coefficient of variance 3-6%) and in a timescale in the range of 10 - 20 ps were delivered. The dose was characterised during irradiation and found in agreement with Monte Carlo simulations Cell survival and DNA double strand break repair dynamics were studied for both cell lines using clonogenic assay and 53BP1 foci formation and results were compared with reference x-rays at a dose rate of 0.49 Gy/min.
Results
Results from clonogenic assays of both cell lines up to 3 Gy are well fitted by a linear quadratic model with α = (0.68±0.08) Gy−1 and β = (0.01±0.01) Gy−2 for human skin fibroblasts and α = (0.51 ± 0.14) Gy−1 and β = (0.01 ± 0.01) Gy−2 for cancer stem cells. Compared to irradiation at 0.49 Gy/min, our experimental results indicate no statistically significant difference in cell survival rate for doses up to 3 Gy, even though a significant increase in the α parameter is observed, possibly hinting at more complex damages. Foci measurements show no significant difference between irradiations at 1011 Gy/s and 0.49 Gy/min.
Conclusions
This study demonstrates the possibility of performing radiobiological studies with picosecond-scale laser-generated electron beams and ultra-high dose rates of 1010−1011 Gy/s. Preliminary results indicate, within statistical uncertainties, a significant increase of the α parameter, possible indication of the occurrence of more complex damage induced
This study aims to demonstrate, for the first time, the possibility of irradiating biological cells with Gy-scale doses delivered over single bursts of picosecond-scale electron beams, resulting in unprecedented dose rates of 1010 - 1011 Gy/s.
Methods and Materials
Cancer stem cells and human skin fibroblasts were irradiated with MeV-scale electron beams from a laser-driven source. Doses up to 3 Gy per pulse with a high spatial uniformity (coefficient of variance 3-6%) and in a timescale in the range of 10 - 20 ps were delivered. The dose was characterised during irradiation and found in agreement with Monte Carlo simulations Cell survival and DNA double strand break repair dynamics were studied for both cell lines using clonogenic assay and 53BP1 foci formation and results were compared with reference x-rays at a dose rate of 0.49 Gy/min.
Results
Results from clonogenic assays of both cell lines up to 3 Gy are well fitted by a linear quadratic model with α = (0.68±0.08) Gy−1 and β = (0.01±0.01) Gy−2 for human skin fibroblasts and α = (0.51 ± 0.14) Gy−1 and β = (0.01 ± 0.01) Gy−2 for cancer stem cells. Compared to irradiation at 0.49 Gy/min, our experimental results indicate no statistically significant difference in cell survival rate for doses up to 3 Gy, even though a significant increase in the α parameter is observed, possibly hinting at more complex damages. Foci measurements show no significant difference between irradiations at 1011 Gy/s and 0.49 Gy/min.
Conclusions
This study demonstrates the possibility of performing radiobiological studies with picosecond-scale laser-generated electron beams and ultra-high dose rates of 1010−1011 Gy/s. Preliminary results indicate, within statistical uncertainties, a significant increase of the α parameter, possible indication of the occurrence of more complex damage induced
| Original language | English |
|---|---|
| Pages (from-to) | 1105-1109 |
| Journal | International Journal of Radiation Oncology Biology Physics |
| Volume | 118 |
| Issue number | 4 |
| Early online date | 22 Feb 2024 |
| DOIs | |
| Publication status | Published - 15 Mar 2024 |
