Durante, M.

Furusawa, Y.

Hirayama, R.

Scifoni, E.

Tinganelli, W.

GSI Repository

GSI-NIRS International Open Laboratory: filling the gap of oxygen effect measurements*M. Durante1,2,3, W. Tinganelli1,3,4, E. Scifoni1, R. Hirayama,4 and Y. Furusawa3, 41GSI, Darmstadt, Germany; 2TUD, Darmstadt, Germany; 3 IOL, International Open Laboratory; 4NIRS, Chiba, JapanThe  main  goal  of  the  GSI-NIRS  International  Open Laboratory (IOL) Radiation Quality Research Unit is the verification,  with  a  set  of  experimental  OER  (Oxygen Enhancement Ratio) data points of a semi-empirical model developed at GSI that is being used for the implementation of  adaptive  treatment  planning  in  TRiP98  [1,2],  for specifically  targeting  hypoxic  tumors. The  longstanding lack  of  experimental  measurements  exactly  in  those conditions of oxygen concentration (pO2) and linear energy transfer (LET) most relevant for a clinical application of the method,  guided  the  need  of  this  project,  joining the  two most  experienced  groups  worldwide (GSI  and  NIRS)  on hypoxic  irradiation  with  ion  beams.   The  IOL kick-off meeting  was  held  in  Darmstadt  on  05.09.2011.  The last progress  report  meeting  was  held  in  Chiba,  Japan  on 22.01.2013, where actual results were presented and further projects and collaborations between units were discussed.Figure1:   Experimental  setup  for  hypoxic  irradiation  at several tunable oxygen concentrations adopted at NIRS for the present project, with ion beams and X-rays.IOL Status reportExperimental points about the complete anoxic condition (0%)  and  a  partially  hypoxic  (0.5%)  one  have  been measured  at  NIRS  with  CHO  cells  and  a  dedicated experimental  setup  (Figure  1)  to  verify  our  model.  The results (Figure 2) shown a reasonable agreement with the prediction model, especially in the slope region, suggestinga  slight  adjustment  of  the  low  LET  asymptote  for  the specific cell line. The higher OER value found for the very high LET, is due to the large ions fragmentation, since we used the HIMAC-NIRS passive beam experimental room.Figure 2: Model of the dependence of OER from LET for different oxygen partial pressures under implementation in TRiP98  and independent  experiments  performed  at  GSI-IOL/NIRS (points). CollaborationsIn  the  same  time,  our  unit  started  the  planned collaborations with the Particle Therapy Molecular  Target Unit  (Profs.  Nickoloff,  Colorado  State  University  and Jeggo, University of Sussex). Several other projects related to the hypoxic irradiation  with  ion  beams were initiated, namely  related  to  the  Phoenix  rising effect  [3],  and suppression of  the tumor immunogenicity capacity [4]. A link with the Radiation Response Model Unit for alternative OER modeling is also planned.OUTLOOKFurther  OER experiments are planned at 2% and 0.15% oxygen concentrations. Selected other  experiments at LET 75-30  keV/m  at  anoxia  and  0.5% oxygen  will  be  also performed. About the  Phoenix rising effect we planned to verify with a specific experiment the molecular pathway. In February 2013 we will start the immune system-mediated radiation effect experiments. References[1] E. Scifoni et al., Phys. Med . Biol. submitted[2]  E.Scifoni  et al., this report.[3] Q. Huang et al., Nat. Med. 17 (2011): 860-6.[4] S. Formenti and S. Demaria, Lancet Oncol. 10 (2009) 718-726 * Supported by the NIRS IOL grant to GSI.#m.durante@gsi.deHEALTH-44 GSI SCIENTIFIC REPORT 2012468

GSI-NIRS International Open Laboratory: filling the gap of oxygen effect measurements

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GSI-NIRS International Open Laboratory: filling the gap of oxygen effect measurements

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