Document Type : Original Research

Authors

PhD, Department of Physics, Faculty of Sciences, University of Birjand, Birjand, Iran

Abstract

Background: The amount of average dose enhancement in tumor loaded with 10B may vary due to various factors in boron neutron capture therapy.
Objective: This study aims to evaluate dose enhancement in tumor loaded with 10B under influence of various factors and investigate the dependence of this dose enhancement on neutron spectra changes.
Material and Methods: In this simulation study, using 252Cf as a neutron source, the average in-tumor dose enhancement factor (DEF) and neutron energy spectra were calculated for various 10B concentrations, phantom with different sizes and for different tumor locations, through MCNPX code.
Results: Obtained results showed that the values of average DEF rise with increasing 10B concentration, phantom diameter (˂ 30 cm) and tumor distance from the source, but this increment is not linear.
Conclusion: It was concluded that inequality in average dose enhancement rates, in tumor loaded with 10B under influence of various factors in boron neutron capture therapy, is due to non-identical changes of both the thermal neutron flux with increasing same number of 10B atoms and same thickness of scattering material, and the thermal to fast neutron flux ratio with increasing equal distances of tumor from the source.

Keywords

  1. Enger SA, Rezaei A, Munck af Rosenschold P, Lundqvist H. Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy. Med Phys. 2006;33:46-51. doi: 10.1118/1.2146050. PubMed PMID: 16485408.
  2. Barth RF, Coderre JA, Vicente MG, Blue TE. Boron neutron capture therapy of cancer: current status and future prospects. Clin Cancer Res. 2005;11:3987-4002. doi: 10.1158/1078-0432.CCR-05-0035. PubMed PMID: 15930333.
  3. Miyatake S, Kawabata S, Hiramatsu R, Kuroiwa T, Suzuki M, Kondo N, et al. Boron Neutron Capture Therapy for Malignant Brain Tumors. Neurol Med Chir (Tokyo). 2016;56:361-71. doi: 10.2176/nmc.ra.2015-0297. PubMed PMID: 27250576; PubMed Central PMCID: PMCPMC4945594.
  4. Amin Shokr A. Current Status of Neutron Capture Therapy. IAEA-TECDOC-1223. Vienna: International Atomic Energy Agency, 2001.
  5. Wierzbicki JG, Maruyama Y, Porter AT. Measurement of augmentation of 252Cf implant by 10B and 157Gd neutron capture. Med Phys. 1994;21:787-90. doi: 10.1118/1.597324. PubMed PMID: 7935215.
  6. Beach JL, Schroy CB, Ashtari M, Harris MR, Maruyama Y. Boron neutron capture enhancement of 252Cf brachytherapy. Int J Radiat Oncol Biol Phys. 1990;18:1421-7. doi: 10.1016/0360-3016(90)90317-d. PubMed PMID: 2370192.
  7. Carlsson J, Hartman T, Grusell E. Dose enhancement in fast neutron tumour therapy due to neutron captures in 10B. Acta Oncol. 1994;33:315-22. doi: 10.3109/02841869409098423. PubMed PMID: 8018361.
  8. Krstic D, Jovanovic Z, Markovic V, Nikezic D, Urosevic V. MCNP simulation of the dose distribution in liver cancer treatment for BNC therapy. Open Physics. 2014;12:714-8. doi: 10.2478/s11534-014-0507-2.
  9. Rivard MJ, Wierzbicki JG, Van Den Heuvel F, Martin RC, McMahon RR. Clinical brachytherapy with neutron emitting 252Cf sources and adherence to AAPM TG-43 dosimetry protocol. Med Phys. 1999;26:87-96. doi: 10.1118/1.598472. PubMed PMID: 9949403.
  10. Pelowitz DB. MCNPX user’s manual, version 2.6. 0, LA-CP-07-1473. Los Alamos National Laboratory, Los Alamos (NM). 2008.
  11. Chadwick MB, Barschall HH, Caswell RS, DeLuca PM, Hale GM, Jones DT, et al. A consistent set of neutron kerma coefficients from thermal to 150 MeV for biologically important materials. Med Phys. 1999;26:974-91. doi: 10.1118/1.598601. PubMed PMID: 10436900.
  12. Goorley JT, Kiger Iii WS, Zamenhof RG. Reference dosimetry calculations for neutron capture therapy with comparison of analytical and voxel models. Med Phys. 2002;29:145-56. doi: 10.1118/1.1428758. PubMed PMID: 11865986.
  13. Stoddard D, Hootman H. Cf-252 Shielding Guide. Report DP-1246. 1971. 81p.
  14. Colvett RD, Rossi HH, Krishnaswamy V. Dose distributions around a californium-252 needle. Phys Med Biol. 1972;17:356-64. doi: 10.1088/0031-9155/17/3/302. PubMed PMID: 5070446.
  15. Krishnaswamy V. Calculated depth dose tablets for californium-252 sources in tissue. Phys Med Biol. 1972;17:56-63. doi: 10.1088/0031-9155/17/1/006. PubMed PMID: 5071502.