Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Purpose: Before laser particle accelerators can be used for radiation therapy, the supply of stable, reliable and reproducible beams with sufficient particle intensity and useable energy spectra is required. Moreover, consequences on dosimetry as well as on radiobiological effectiveness have to be investigated for laser-accelerated and therefore ultra-shortly pulsed particle beams with very high pulse dose rate.
Method and Materials: In vitro cell irradiations have been established and performed within the German multi-institutional research project onCOOPtics for both laser-accelerated electron and proton beams.
The experimental setups at two lasers, the 10 TW JETI laser for electron and the 150 TW DRACO laser for proton beams, includes a dedicated system for routine cell sample irradiation and precise determination of applied dose. After extensive tuning and optimization of the laser systems and particle beams as well as test and calibration of all dosimetric components, systematic radiobiological experiments with several tumor and normal tissue cell lines have been performed over the last three years measuring dose-effect-curves for cell survival and DNA double strand break induction.
Results: No significant differences in biological effectiveness between laser-accelerated and conventional electron beams were found, apart from one cell line at one end point. The evaluation of the recently finished proton irradiation campaign is in progress.
Conclusion: Laser accelerators can be used for radiobiological experiments, meeting all necessary requirements like homogeneity, stability and precise dose delivery. Nevertheless, before fulfilling the much higher requirements for clinical application, several improvements concerning i.e. proton energy, spectral shaping and patient safety are necessary.