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

Clinical calculations of physical and biological effective dose distributions in proton and carbon ion therapy using the FLUKA Monte Carlo code

Meeting Abstract

  • A. Mairani - Heidelberg Ion Beam Therapy Center, Heidelberg
  • S. Brons - Heidelberg Ion Beam Therapy Center, Heidelberg
  • F. Cerutti - CERN, Geneva, Switzerland
  • A. Ferrari - CERN, Geneva, Switzerland
  • K. Parodi - Heidelberg Ion Beam Therapy Center, Heidelberg
  • M. Scholz - GSI, Darmstadt
  • F. Sommerer - Heidelberg Ion Beam Therapy Center, Heidelberg

PTCOG 48. Meeting of the Particle Therapy Co-Operative Group. Heidelberg, 28.09.-03.10.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09ptcog129

DOI: 10.3205/09ptcog129, URN: urn:nbn:de:0183-09ptcog1295

Published: September 24, 2009

© 2009 Mairani et al.
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Outline

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Purpose: To implement a Monte Carlo (MC) framework for physical and biological effective dose calculations in ion beam therapy to validate and support analytical treatment planning engines.

Material and Methods: Currently, dedicated or commercial treatment planning systems (TPSs) for ion therapy are essentially analytical codes based on fast performing pencil-beam algorithms. However, MC statistical methods are increasingly considered powerful tools for accurate calculations of dose deposition, since they are assumed to provide a more realistic representation of the physical interactions of the primary beam and the resulting secondary particles. They allow dose evaluation taking into account the realistic patient stoichiometry and anatomy instead of the water-equivalent approach typically exploited by the analytical treatment planning algorithms. This can be particularly advantageous in situations sensitive to lateral scattering (especially for protons), nuclear fragmentation (especially for heavier ions), and in the presence of large density gradients, e.g., due to metallic implants. Finally, MC simulations can provide accurate physical databases to be input into TPSs.

In this work we present our customisation of the FLUKA MC code for CT-based calculations of dose delivery for passively and actively shaped treatment fields in proton and carbon ion therapy. The MC simulations are compared with the results of the analytical treatment planning codes Focus/XiO (Computerised Medical Systems Inc.) and TRiP (TReatment Planning for Particle), which are used in clinical routine for proton and carbon ion therapy at MGH Boston and GSI, respectively.

Results: In general, MC clinical dose distributions are found in good agreement with the analytical calculations, except few cases e.g. in the presence of metallic implants and air/tissue interfaces, and for carbon ions also in the fragmentation tails due to the different treatment of nuclear reactions.

Conclusions: Thanks to the recent efforts made by the FLUKA Collaboration in order to produce reliable nucleus-nucleus event generators in the energy range of therapeutic relevance, the FLUKA Monte Carlo code now represents a valuable choice for accurate CT-based calculations of physical dose deposition not only in proton therapy but also for the entire spectrum of heavier ions of therapeutic relevance.

In addition, thanks to a novel interface with the LEM (Local Effect Model), we are able to perform biological effective dose calculations in ion therapy with FLUKA.