Baumstark-Khan, C.

Berger, T.

Bilski, P.

Burmeister, S.

Chishti, A. A.

Hager, L.

Hajek, M.

Hellweg, C. E.

Koch, K.

La Tessa, C.

Palfalvi, J. K.

Reitz, G.

Sihver, L.

GSI Repository

GSITemplate2007 AO-10-IBER-16 – Ground based radiation field simulation of the MATROSHKA experiment: Physical and Biological Experiments for Radiation Risk Assessment - PART II  T. Berger1, G. Reitz1, C. Baumstark-Khan1, C.E. Hellweg1, K. Koch1, A. A. Chishti1, M. Hajek2, P. Bilski3, J. K. Pálfalvi 4, L. Hager5, S. Burmeister6, L. Sihver7, C. La Tessa8 1DLR, Germany; 2TU Vienna, ATI, Austria; 3IFJ, Poland; 4AERI, Hungary; 5HPA, UK; 6CAU, Germany; 7CTH, Swe-den; 8GSI, Germany One goal of the AO-10-IBER-16 is the irradiation of the ground based model (phantom head) of the MA-TROSHKA phantom equipped with passive (Thermolu-minescence (TLDs) detectors. At the same time the bio-logical part of the experiment includes the survival re-flected by radiation-dependent reduction of growth of stably and constitutively tdTomato expressing human embryonic kidney cells exposed outside and inside the phantom head. Fig. 1. shows the dose distribution inside the phantom head after irradiation with 2Gy 1GeV/n Ti ions as a base-line for intercomparison with cell survival inside the phantom head. Figure 1: Dose distribution inside the phantom head measured with thermoluminescence detectors (2 Gy 1MeV/n Ti ions) Stress-induced gene expression mediated by Nuclear Fac-tor κB (NF-κB) was monitored by means of stably trans-fected HEK-pNF-κB-d2EGFP/Neo L2 cells. In these cells, d2EGFP expression is operated by four NF-κB binding sites (Hellweg et al., J. Biomol. Screen. 8, 511-521, 2003; Hellweg et al., Annals of the New York Acad-emy of Sciences 1091, 191–204,  2006; Hellweg et al., Advances in Space Research 44, 907–916, 2009). NF-κB-dependent gene expression was monitored by flow cytometric detection of d2EGFP, a destabilized form of Enhanced Green Fluorescent Protein (EGFP). Using these cell lines, it was recently shown that NF-κB activation depends on LET and reaches a maximum in the range of 80-300 keV/µm (Hellweg et al., International Journal of Radiation Biology, 87(9), 954–963, 2011; Hellweg et al. Radiation Research 175, 424-431, 2011). The highest biological effectiveness (RBE) in NF-κB activation was observed with argon ions (LET 172 keV/µm) with an RBE of ~9. The experiments at GSI with Ti ions (1GeV/n, LET 108 keV/µm) and Ni ions  (1GeV/n, LET 175 keV/µm) complemented these results and give further inside into the dose-effect relationship and the kinetics of NF-κB dependent gene expression (Fig. 2 A and B). The RBE for NF-κB activation was 4.8 after Ti ions exposure, compared to 200 kV X-rays as reference radiation. Dose / Gy0 2 4 6 8 10 12 14 16%EGFP(+) cells / %        051015202530HEK-pNF-κB-d2EGFP/Neo L2Ti-48 Ions, 1 GeV/n, LET 107 keV/µm A Time (h)0 12 24 36 48% EGFP(+) cells        0510152025302 Gy0 Gy HEK-pNF-κB-d2EGFP Neo L2Ti-48 Ions, 1 GeV/n, LET 107 keV/µm B Figure 2: Induction of NF-κB dependent gene ex-pression in HEK-pNF-κB-d2EGFP/Neo L2 cells after exposure to Ti ions. The expression of the reporter EGFP increases dose-dependently 18 h after expo-sure (A). The NF-κB activation continuously increas-es over two days after exposure to 2 Gy Ti ions (B). Outlook The data acquired during the beam times at GSI in 2011-2012 are being currently further evaluated. These investi-gations include also simulations of the physics experi-ment with GEANT4 Monte Carlo code. Publications on NF-κB dependent gene expression are currently under preparation.  GSI SCIENTIFIC REPORT 2012 HEALTH-65489

AO-10-IBER-16 - Ground based radiation field simulation of the MATROSHKA experiment: Physical and Biological Experiments for Radiation Risk Assessment - PART II

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AO-10-IBER-16 - Ground based radiation field simulation of the MATROSHKA experiment: Physical and Biological Experiments for Radiation Risk Assessment - PART II

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