Determination of water equivalent ratio for some dosimetric materials in proton therapy using MNCPX simulation tool

  • Reza Bagheri
  • Alireza Khorrami MoghaddamEmail author
  • Bakhtiar Azadbakht
  • Mahmoud Reza Akbari
  • Seyed Pezhman Shirmardi


The water equivalent ratio (WER) was calculated for polypropylene (PP), paraffin, polyethylene (PE), polystyrene (PS), polymethyl methacrylate (PMMA), and polycarbonate materials with potential applications in dosimetry and medical physics. This was performed using the Monte Carlo simulation code, MCNPX, at different proton energies. The calculated WER values were compared with National Institute of Standards and Technology (NIST) data, available experimental and analytical results, as well as the FLUKA, SRIM, and SEICS codes. PP and PMMA were associated with the minimum and maximum WER values, respectively. Good agreement was observed between the MCNPX and NIST data. The biggest difference was 0.71% for PS at 150 MeV proton energy. In addition, a relatively large positive correlation between the WER values and the electron density of the dosimetric materials was observed. Finally, it was noted that PE presented the most analogous Depth Dose Characteristics to liquid water.


Water equivalent ratio Proton therapy Dosimetric materials MCNPX code 



The authors thank Dr. M.A. Roshanzamir (Nuclear Science and Technology Research Institute, Iran) for modifying and editing the manuscript.


  1. 1.
    G. Kraft, Tumor therapy with heavy charged particles. Prog. Part. Nucl. Phys. 45, S473–S544 (2000). CrossRefGoogle Scholar
  2. 2.
    W.D. Newhauser, R. Zhang, The physics of proton therapy. Phys. Med. Biol. 60, R155–R209 (2015). CrossRefGoogle Scholar
  3. 3.
    F.M. Khan, J.P. Gibbons, Khan’s the Physics of Radiation Therapy, 5th edn. (Lippincott Williams & Wilkins, Philadelphia, 2014)Google Scholar
  4. 4.
    S. Shirmardi, E. Saniei, M. Erfani et al., Tissue inhomogeneity in proton therapy and investigation of its effects on BRAGG peak by using MCNPX code. Int. J. Radiat. Res. 12, 335–341 (2014)Google Scholar
  5. 5.
    H. Paganetti, Monte Carlo method to study the proton fluence for treatment planning. Med. Phys. 2519, 2370–2375 (1998). CrossRefGoogle Scholar
  6. 6.
    W. Levin, H. Kooy, J. Loeffler et al., Proton beam therapy. Br. J. Cancer 93, 849 (2005). CrossRefGoogle Scholar
  7. 7.
    V.P. Singh, N.M. Badiger, N. Kucuk, Assessment of methods for estimation of effective atomic numbers of common human organ and tissue substitutes: waxes, plastics and polymers. Radioprotection 49, 115–121 (2014). CrossRefGoogle Scholar
  8. 8.
    V.P. Singh, N.M. Badiger, Effective atomic numbers, electron densities, and tissue equivalence of some gases and mixtures for dosimetry of radiation detectors. Nucl. Technol. Radiat. 27, 117–124 (2012). CrossRefGoogle Scholar
  9. 9.
    L. Al-Sulaiti, D. Shipley, R. Thomas et al., Water equivalence of various materials for clinical proton dosimetry by experiment and Monte Carlo simulation. Nucl. Instrum. Methotds Phys. Res. A 619, 344–347 (2010). CrossRefGoogle Scholar
  10. 10.
    U. Schneider, P. Pemler, J. Besserer et al., The water equivalence of solid materials used for dosimetry with small proton beams. Med. Phys. 29, 2946–2951 (2002). CrossRefGoogle Scholar
  11. 11.
    S. Icru, Tissue Substitutes in Radiation Dosimetry and Measurement, Report 44 (International Commission on Radiation Units and Measurements, Bethesda, 1989)Google Scholar
  12. 12.
    S. Icru, Powers and Ranges for Protons and Alpha Particles, Report 49 (International Commission on Radiation Units and Measurements, Bethesda, 1993), p. 23Google Scholar
  13. 13.
    V.P. Singh, M.E. Medhat, Mass attenuation coefficients of composite materials by Geant4, XCOM and experimental data: comparative study. Nucl. Technol. Radiat. 169, 800–807 (2014). CrossRefGoogle Scholar
  14. 14.
    V.P. Singh, S.P. Shirmardi, M.E. Medhat et al., Determination of mass attenuation coefficient for some polymers using Monte Carlo simulation. Vacum 119, 284–288 (2015). CrossRefGoogle Scholar
  15. 15.
    R. Zhang, W.D. Newhauser, Calculation of water equivalent thickness of materials of arbitrary density, elemental composition and thickness in proton beam irradiation. Phys. Med. Biol. 54, 1383–1395 (2009). CrossRefGoogle Scholar
  16. 16.
    W. Newhauser, J. Fontenot, N. Koch et al., Monte Carlo simulations of the dosimetric impact of radiopaque fiducial markers for proton radiotherapy of the prostate. Phys. Med. Biol. 52, 2937–2952 (2007). CrossRefGoogle Scholar
  17. 17.
    R. Zhang, P.J. Taddei, M.M. Fitzek et al., Water equivalent thickness values of materials used in beams of protons, helium, carbon and iron ions. Phys. Med. Biol. 55, 2481–2493 (2010). CrossRefGoogle Scholar
  18. 18.
    J.F. Janni, Proton range-energy tables, 1 keV–10 GeV, energy loss, range, path length, time-of-flight, straggling, multiple scattering, and nuclear interaction probability. Part I. For 63 compounds. At. Data Nucl. Data 27, 147–339 (1982). CrossRefGoogle Scholar
  19. 19.
    M.R. Akbari, H. Yousefnia, E. Mirrezaei, Calculation of water equivalent ratio of several dosimetric materials in proton therapy using FLUKA code and SRIM program. Appl. Radiat. Isot. 90, 89–93 (2014). CrossRefGoogle Scholar
  20. 20.
    P. de Vera, I. Abril, R. Garcia-Molina, Water equivalent properties of materials commonly used in proton dosimetry. Appl. Radiat. Isot. 83, 122–127 (2014). CrossRefGoogle Scholar
  21. 21.
    A. Konefał, P. Szaflik, W. Zipper, Influence of the energy spectrum and spatial spread of proton beams used in eye tumor treatment on the depth-dose characteristics. Nukleonika 55, 313–316 (2010)Google Scholar
  22. 22.
    M.F. Moyers, M. Sardesai, S. Sun et al., Ion stopping powers and CT numbers. Med. Dosim. 35, 179–194 (2010). CrossRefGoogle Scholar
  23. 23.
    D. Pellowitz, MCNPX User’s Manual, version 2.6. 0. Los Alamos Report No LA CP 2:408 (2007)Google Scholar
  24. 24.
    R. Bagheri, A.K. Moghaddam, A. Yousefi, Gamma-ray shielding study of light to heavyweight concretes using MCNP-4C code. Nucl. Sci. Technol. 15, 2–7 (2017). CrossRefGoogle Scholar
  25. 25.
    H. Paganetti, Dose to water versus dose to medium in proton beam therapy. Phys. Med. Biol. 54, 4399–4421 (2009). CrossRefGoogle Scholar
  26. 26.
    S. Icru, Stopping Powers for Electrons and Positrons, Report 37 (International Commission on Radiation Units and Measurements, Bethesda, 1984)Google Scholar
  27. 27.
    S. Rossomme, H. Palmans, D. Shipley et al., Conversion from dose-to-graphite to dose-to-water in an 80 MeV/A carbon ion beam. Phys. Med. Biol. 58, 5363–5380 (2013). CrossRefGoogle Scholar
  28. 28.
    H. Palmans, J.E. Symons, J.M. Denis et al., Fluence correction factors in plastic phantoms for clinical proton beams. Phys. Med. Biol. 47, 3055–3071 (2002). CrossRefGoogle Scholar
  29. 29.
    G.F. Knoll, Radiation Detection and Measurement, 3rd edn. (Wiley, New York, 2000)Google Scholar

Copyright information

© China Science Publishing & Media Ltd. (Science Press), Shanghai Institute of Applied Physics, the Chinese Academy of Sciences, Chinese Nuclear Society and Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Reza Bagheri
    • 1
  • Alireza Khorrami Moghaddam
    • 2
    Email author
  • Bakhtiar Azadbakht
    • 3
  • Mahmoud Reza Akbari
    • 4
  • Seyed Pezhman Shirmardi
    • 1
  1. 1.Radiation Application Research SchoolNuclear Science and Technology Research InstituteTehranIran
  2. 2.Radiology Department, Allied FacultyMazandaran University of Medical Sciences (MazUMS)SariIran
  3. 3.Department of Medical EngineeringBorujerd Branch, Islamic Azad UniversityBorujerdIran
  4. 4.Therapy Level LaboratorySecondary Standard Dosimetry LaboratoryKarajIran

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