Radiobiological Characterization of Two Therapeutic Proton Beams With Different Initial Energy Spectra Used at the Institut Curie Proton Therapy Center in Orsay
- Institut Curie, Centre de Protontherapie d'Orsay, Centre Universitaire, Orsay (France)
- Institut Curie, Centre Universitaire, Orsay (France)
Purpose: Treatment planning in proton therapy uses a generic value for the relative biological efficiency (RBE) of 1.1 throughout the spread-out Bragg peak (SOBP) generated. In this article, we report on the variation of the RBE with depth in the SOBP of the 76- and 201-MeV proton beams used for treatment at the Institut Curie Proton Therapy Center in Orsay. Methods and Materials: The RBE (relative to {sup 137}Cs {gamma}-rays) of the two modulated proton beams at three positions in the SOBP was determined in two human tumor cells using as endpoints clonogenic cell survival and the incidence of DNA double-strand breaks (DSBs) as measured by pulse-field gel electrophoresis without and with enzymatic treatment to reveal clustered lesions. Results: The RBE for induced cell killing by the 76-MeV beam increased with depth in the SOBP. However for the 201-MeV protons, it was close to that for {sup 137}Cs {gamma}-rays and did not vary significantly. The incidence of DSBs and clustered lesions was higher for protons than for {sup 137}Cs {gamma}-rays, but did not depend on the proton energy or the position in the SOBP. Conclusions: Until now, little attention has been paid to the variation of RBE with depth in the SOBP as a function of the nominal energy of the primary proton beam and the molecular nature of the DNA damage. The RBE increase in the 76-MeV SOBP implies that the tumor tissues at the distal end receives a higher biologically equivalent dose than at the proximal end, despite a homogeneous physical dose. This is not the case for the 201-MeV energy beam. The precise determination of the effects of incident beam energy, modulation, and depth in tissues on the linear energy transfer-RBE relationship is essential for treatment planning.
- OSTI ID:
- 22054450
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 81, Issue 4; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
Similar Records
TU-EF-304-10: Efficient Multiscale Simulation of the Proton Relative Biological Effectiveness (RBE) for DNA Double Strand Break (DSB) Induction and Bio-Effective Dose in the FLUKA Monte Carlo Radiation Transport Code
SU-F-T-682: In-Vivo Simulation of the Relative Biological Effectiveness in Proton Therapy Using a Monte Carlo Method