Author: Christoph Bert, Leon Brückner, Luitpold Distel, Julian Freier, Peter Hommelhoff, Bastian Löhrl 👨🔬
Affiliation: Department of Radiation Oncology, Uniklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Department Physik, Friedrich-Alexander Universität Erlangen-Nürnberg 🌍
Purpose: Low energy electron (LEE) bunches in the kilo electronvolt (keV) range are thought to have a high relative biological effectiveness (RBE). To investigate this, it is necessary to establish reliable dosimetry. The aim for future applications is to emit LEE from a nanophotonic electron accelerator, i.e. a laser accelerator on a chip, installed in an endoscopic system. This, combined with the high RBE and low penetration depth of LEE, could enable very localised cancer treatment.
Methods: A methodology was developed for the dosimetric calibration of unlaminated EBT3 GafChromic films for LEE radiation, using measurements with high energy radiation and simulation data. This facilitates the investigation of their effects on cells and comparison with other radiation damage. An ultrafast pulsed electron source, utilizing photoemission from an array of gold needle tips, was employed for the irradiation of cells with electron energies up to 50 keV. Human primary fibroblasts were exposed to .
Results: The calibration of the EBT3 GafChromic films enabled the assessment of the impact of LEE radiation on various cell types. Irradiation-induced DNA double-strand breaks were detected and visualized using γH2AX detection. By this the biological damage, in this context the density of double-strand breaks and survivability, can be quantitatively compared to X-ray radiation, shedding light on the potential advantages of LEE electron beams.
Conclusion: We present a methodology for calibrating unlaminated EBT3 Gafchromic films for low-energy radiation. Using this, the impact of LEE radiation on cells can be compared with high energy radiation. This research establishes the foundation for exploring future novel therapeutic approaches that utilize future laser accelerator on a chip technology.