gms | German Medical Science

48th Meeting of the Particle Therapy Co-Operative Group

Particle Therapy Co-Operative Group (PTCOG)

28.09. - 03.10.2009, Heidelberg

On the long way to laser particle therapy: Results of radiobiological experiments with laser accelerated electronsand future experiments with laser accelerated protons

Meeting Abstract

  • Chr. Richter - TU Dresden, Medical Faculty C.G. Carus, OncoRay – Radiation Research in Oncology, Dresden
  • E. Beyreuther - Forschungszentrum Dresden-Rossendorf, Dresden
  • W. Enghardt - TU Dresden, Medical Faculty C.G. Carus, OncoRay – Radiation Research in Oncology, Dresden
  • M. Kaluza - Friedrich-Schiller-Universität Jena, Jena
  • L. Karsch - TU Dresden, Medical Faculty C.G. Carus, OncoRay – Radiation Research in Oncology, Dresden
  • L. Laschinksy - TU Dresden, Medical Faculty C.G. Carus, OncoRay – Radiation Research in Oncology, Dresden
  • E. Lessmann - Forschungszentrum Dresden-Rossendorf, Dresden
  • D. Naumburger - TU Dresden, Medical Faculty C.G. Carus, OncoRay – Radiation Research in Oncology, Dresden
  • M. Nicolai - Friedrich-Schiller-Universität Jena, Jena
  • J. Pawelke - TU Dresden, Medical Faculty C.G. Carus, OncoRay – Radiation Research in Oncology, Dresden
  • M. Sobiella - Forschungszentrum Dresden-Rossendorf, Dresden
  • R. Sauerbrey - Forschungszentrum Dresden-Rossendorf, Dresden
  • H.-P. Schlenvoigt - Friedrich-Schiller-Universität Jena, Jena
  • M. Schürer - TU Dresden, Medical Faculty C.G. Carus, OncoRay – Radiation Research in Oncology, Dresden
  • M. Baumann - TU Dresden, Medical Faculty C.G. Carus, OncoRay – Radiation Research in Oncology, Dresden

PTCOG 48. Meeting of the Particle Therapy Co-Operative Group. Heidelberg, 28.09.-03.10.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09ptcog162

DOI: 10.3205/09ptcog162, URN: urn:nbn:de:0183-09ptcog1629

Veröffentlicht: 24. September 2009

© 2009 Richter et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Background: The novel technology of particle acceleration based on high intensity laser systems promises proton therapy accelerators of compact size and reasonable costs. Laser acceleration results in ultra-short pulsed (~100 fs) particle beams with very high pulse dose-rate (in the order of 1012 Gy/min). These beams have to be characterized with regard to their radiobiological and dosimetric properties and must allow a stable and reliable dose delivery before a conceivable clinical application is possible. The results of the worldwide first systematic in vitro cell irradiation experiments with laser accelerated electrons will be presented. Moreover, the developed dosimetric requirements for cell irradiation experiments with laser accelerated protons of low energy will be presented.

Material and methods: The experiments with laser accelerated electrons have been performed at the Jena Titanium:Sapphire (JeTi) 10 TW laser system. Laser pulses were focused into a helium gas jet, accelerating electrons to energies of up to 20 MeV. Cell irradiations were realized for two squamous cell carcinoma and two normal tissue cell lines in a dose range from 0.3 Gy to 10 Gy. For irradiation control an ionization chamber and a Faraday Cup provided online dose information. Additional Gafchromic EBT radiochromic films were used for retrospective exact dose determination at the cell site. Referring to irradiation the survival fraction was determined and furthermore DNA double strand breaks 24 h after irradiation were analyzed.

Moreover, an integrated dosimetry and cell irradiation device (IDCID) has been designed and optimized for laser accelerated proton beams of low energy. It integrates an online- and absolute dosimeter system in combination with an in vitro cell irradiation device. Furthermore, the different detectors and dosimeters of the IDCID have been tested and cross calibrated at the tandem accelerator of the Forschungszentrum Dresden-Rossendorf. For the application of radiochromic films within the IDCID, EBT films have been calibrated for different proton spectra at the eye irradiation facility of the Helmholtz Zentrum Berlin.

Results: The determined dose-effect-curves for laser accelerated electrons show in general a reduced biological effectiveness in comparison with continuous 200kVp X-rays. The effect of the high pulse dose-rate among the possible reasons will be discussed. Furthermore, calibration curves for EBT films have been determined for 6 proton energies between 5 and 62 MeV. For energies between 10 and 62 MeV no significant energy dependence was found. Moreover, results of the optimization and cross calibration of the detectors included in the IDCID will be shown.

Conclusion: A laser electron accelerator was successfully used to perform long-time systematic in vitro cell irradiations. Further cell irradiation experiments with laser accelerated protons from a 150 TW laser system are prepared.

This work was supported by the BMBF, grant no. 03ZIK445