Simulation of the BNCT of Brain Tumors Using MCNP Code: Beam Designing and Dose Evaluation

Document Type : Original Paper

Authors

1 Physics Department, K.N. Toosi University of Technology, Tehran, Iran.

2 Physics Department, K.N. Toosi University of Technology, Tehran, Iran

Abstract

Introduction
BNCT is an effective method to destroy brain tumoral cells while sparing the healthy tissues. The recommended flux for epithermal neutrons is 109 n/cm2s, which has the most effectiveness on deep-seated tumors. In this paper, it is indicated that using D-T neutron source and optimizing of Beam Shaping Assembly (BSA) leads to treating brain tumors in a reasonable time where all IAEA recommended criteria are met.
Materials and Methods
The proposed BSA based on a D-T neutron generator consists of a neutron multiplier system, moderators, reflector, and collimator. The simulated Snyder head phantom is used to evaluate dose profiles in tissues due to the irradiation of designed beam. Monte Carlo Code, MCNP-4C, was used in order to perform these calculations.  
Results
The neutron beam associated with the designed and optimized BSA has an adequate epithermal flux at the beam port and neutron and gamma contaminations are removed as much as possible. Moreover, it was showed that increasing J/Φ, as a measure of beam directionality, leads to improvement of beam performance and survival of healthy tissues surrounding the tumor.
Conclusion
According to the simulation results, the proposed system based on D-T neutron source, which is suitable for in-hospital installations, satisfies all in-air parameters. Moreover, depth-dose curves investigate proper performance of designed beam in tissues. The results are comparable with the performances of other facilities.

Keywords

Main Subjects


  1. Yamamoto T, Nakai K, Matsumura A. Boron neutron capture therapy for glioblastoma. Cancer letters. 2008;262(2):143-52.
  2. Ghassoun J, Chkillou B, Jehouani A. Spatial and spectral characteristics of a compact system neutron beam designed for BNCT facility. Appl Radiat Isot. 2009 Apr;67(4):560-4.
  3. Zamenhof RG, Murray BW, Brownell GL, Wellum GR, Tolpin EI. Boron neutron capture therapy for the treatment of cerebral gliomas. I. Theoretical evaluation of the efficacy of various neutron beams.Med Phys. 1975 Mar-Apr;2(2):47-60.
  4. Moss R, Stecher-Rasmussen F, Rassow J, Morrissey J, Voorbraak W, Verbakel W, et al. Procedural and practical applications of radiation measurements for BNCT at the HFR Petten. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 2004;213:633-6.
  5. Cerullo N, Esposito J, Leung KN, Custodero S. An irradiation facility for Boron Neutron Capture Therapy application based on a radio frequency driven D–T neutron source and a new beam shaping assembly. Review of scientific instruments. 2002;73(10):3614-8.
  6. IAEA-TECDOC-1223. 2001, Current status of neutron capture therapy. International Atomic Energy Agency.
  7. Auterinen I, Serén T, Anttila K, Kosunen A, Savolainen S. Measurement of free beam neutron spectra at eight BNCT facilities worldwide. Appl Radiat Isot. 2004 Nov;61(5):1021-6.
  8. Verbeke JM, Vujic JL, Leung KN. Neutron beam optimization for boron neutron capture therapy using the DD and DT high-energy neutron sources. Nuclear technology. 2000;129(2):257-78.
  9. Briesmeister JF. MCNP–A General Monte Carlo N-Particle Transport Code.Version 4C, LA-13709-M, Los Alamos National Laboratory. 2000.
  10. Martín G, Abrahantes A. A conceptual design of a beam-shaping assembly for boron neutron capture therapy based on deuterium-tritium neutron generators. Med Phys. 2004 May;31(5):1116-22.
  11. Rasouli FS, Masoudi SF, Kasesaz Y. Design of a model for BSA to meet free beam parameters for BNCT based on multiplier system for D-T neutron source.Ann Nucl Energy 2012;39:18-25.
  12. Sakamoto S, Kiger III WS, Harling OK. Sensitivity studies of beam directionality, beam size, and neutron spectrum for a fission converter-based epithermal neutron beam for boron neutron capture therapy. Med Phys. 1999 Sep;26(9):1979-88.
  13. Snyder WS, Ford MR, Warner GG, Fischer HL. Estimates of absorbed fractions for monoenergetic photon sources uniformly distributed in various organs of heterogeneous phantom, MIRD. J. Nucl. Med. Suppl.1969 Aug:suppl 3:7-52.
  14. Palmer MR, Goorley JT, Kiger WS, Busse PM, Riley KJ, Harling OK, et al. Treatment planning and dosimetry for the Harvard-MIT Phase I clinical trial of cranial neutron capture therapy. Int J Radiat Oncol Biol Phys. 2002 Aug 1;53(5):1361-79.
  15. Liu HB, Greenberg DD, Capala J, Wheeler FJ. An improved neutron collimatorfor brain tumor irradiations in clinical boron neutron capture therapy. Med Phys. 1996 Dec;23(12):2051-60.
  16. Kiger III WS, Sakamoto S, Harling O. Neutronic design of a fission converter-based epithermal neutron beam for neutron capture therapy. Nuclear science and engineering. 1999;131(1):1–22.
  17. Barth RF, Coderre JA, Vicente MG, Blue TE. Boron neutron capture therapy of cancer: current status and future prospects. Clin Cancer Res. 2005 Jun 1;11(11):3987-4002.
  18. Rahmani F, Shahriari M. Beam shaping assembly optimization of Linac based BNCT and in-phantom depth dose distribution analysis of brain tumors for verification of a beam model. Annals of Nuclear Energy. 2011;38(2):404-9.
  19. ICRU Report 46, 1992.Photon, Electron, Proton, and Neutron Interaction Data for Body Tissues. International Committee on Radiation Units and Measurements, Bethesda, MD.
  20. ICRU Report 63, 2000.Nuclear Data for Neutron and Proton Radiotherapy and for Radiation Protection. International Committee on Radiation Units and Measurements, Bethesda, MD.