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

Tissue equivalence of some phantom materials for proton beams

Meeting Abstract

  • V. Vasiliev - Institute for Nuclear Research, Russian Academy of Sciences, Moscow, Russian Federation
  • V. Kostyuchenko - Institute for Theoretical and Experimental Physics, Moscow, Russian Federation
  • O. Riazantsev - Institute for Theoretical and Experimental Physics, Moscow, Russian Federation
  • V. Khaibullin - Institute for Theoretical and Experimental Physics, Moscow, Russian Federation
  • S. Samarin - Russian Federal Nuclear Center – Zababakhin Institute of Applied Physics, Snezhinsk, Russian Federation
  • A. Uglov - Russian Federal Nuclear Center – Zababakhin Institute of Applied Physics, Snezhinsk, Russian Federation

PTCOG 48. Meeting of the Particle Therapy Co-Operative Group. Heidelberg, 28.09.-03.10.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09ptcog215

DOI: 10.3205/09ptcog215, URN: urn:nbn:de:0183-09ptcog2152

Veröffentlicht: 24. September 2009

© 2009 Vasiliev 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

Tissue and water equivalence of some phantom materials originally developed for conventional radiation therapy was investigated on the ITEP medical proton beam. The Bragg curve was measured for three variants of Plastic Water, Lung, Adipose, Muscle and Compact bone substitute materials (CIRS Inc., USA) and liquid water by a semiconductor diode and a plane-parallel ionization chamber PPC05 (Scanditronix-Wellhöfer). The detector was inserted in an adapter plate and aligned with the beam axis, sample plates from 1 to 20 mm of thickness were added in front of the detector. Measurements in liquid water were performed with a PMMA water tank with a thin side window and 3D detector positioner with remote control. A Rogovsky coil was used to measure initial proton current in each pulse.

CSDA proton ranges were derived from measured Bragg peaks and used to estimate linear stopping power ratios for protons of therapy energies (up to 160 MeV). Spatial resolution at the Bragg peak was 1 mm according to the minimal thickness of the plates. Plastic to water range ratios were compared with respective theoretical data obtained from the PSTAR database (NIST, USA).

These experiments were simulated with the Monte Carlo method.

Range ratios for the water equivalent substitutes were close to respective values for liquid water; the difference was from –1.2 to +0.2%. The best agreement was demonstrated by the Plastic Water DT sample. Data for bone, adipose and muscle substitutes agree within 1.0, 3.9 and 1.7% with respective reference values. Thus, at least water and bone substitutes simulate the stopping power of original materials with sufficient accuracy and can be used for dosimetry and QA tasks on medical proton beams. Further investigation on the contributions of scattering power and inelastic nuclear reactions is planned.

The work was in part supported by the ISTC, Grant #3563.