An international journal published by K. N. Toosi University of Technology

Document Type : Research Article


Department of Physics, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran, Iran


‎Due to the selectively treating tumors and largely sparing normal neighboring cells‎, ‎Boron Neutron Capture Therapy (BNCT) continues to be of special significance and interest for wide groups of researchers‎. One of the most important challenges in this context is to design an optimized beam based on an appropriate neutron source‎. ‎The‎ ‎recent studies‎, ‎focused on investigating neutron sources as alternatives‎ ‎for nuclear reactors‎, ‎revealed the high potential of electron linac-based photoneutron sources to improve the efficiency of this‎ treatment method‎. ‎Inquiring about the efficiency of a layered model of beam shaping assembly (BSA) for photoneutron sources to be used in BNCT of deep tumors is the main subject of this simulation study‎. This model‎, ‎unlike the traditional BSA in which the reflector surrounds the whole moderator‎, includes many concentric cylinders of reflectors and moderators‎. ‎The MCNPX simulations for various primary energies show that the layered model results in more appropriate beam characteristics compared with that of the common geometry‎. ‎Moreover‎, ‎the parameters governing the beam properties such as the thickness of the layers‎, ‎moderator/reflector and collimator lengths‎, ‎and the thickness of the surrounding reflector have been investigated‎. ‎The results are encouraging and‎ ‎offer new ways to accomplish more researches in‎ ‎studies on the BNCT technique‎.


• Photoneutron sources of 25 MeV and 30 MeV have been considered for BNCT of deep tumors.
• A layered reflector/moderator BSA model has been designed to be used for electron linac photoneutron sources.
• The IAEA criteria have been considered to optimize the BSA cells.
• The results show considerable effect of the layered model on improving the in-air parameters for photoneutron sources.


Capoulat, M., Minsky, D., and Kreiner, A. (2011). Applicability of the 9Be(d, n)10B reaction to AB-BNCT skin and deep tumor treatment. Applied Radiation and Isotopes, 69(12):1684–1687.
Cerullo, N., Esposito, J., and Leung, K. (2002). Irradiation facility for boron neutron capture therapy application based on a RF-driven D–T neutron source and a new beam shaping assembly. Review of scientific instruments, 73(2):938–938.
Durisi, E., Zanini, A., Manfredotti, C., et al. (2007). Design of an epithermal column for BNCT based on D–D fusion neutron facility. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 574(2):363–369.
Eshwarappa, K., Siddappa, K., Kashyap, Y., et al. (2005). Estimation of photoneutron yield from beryllium target irradiated by variable energy microtron-based bremsstrahlung radiation. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 540(2-3):412–418.
Ganjeh, Z. A. and Masoudi, S. F. (2014). Neutron beam optimization based on a 7Li(p, n)7Be reaction for treatment of deep-seated brain tumors by BNCT. Chinese Physics C, 38(10):108203.
IAEA (2001). Current status of neutron capture therapy. IAEA-TECDOC-1223.
Jallu, F., Lyoussi, A., Payan, E., et al. (1999). Photoneutron production in tungsten, praseodymium, copper and beryllium by using high energy electron linear accelerator. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 155(4):373–381.
Kasesaz, Y., Khalafi, H., and Rahmani, F. (2014). Design of an epithermal neutron beam for BNCT in thermal column of Tehran research reactor. Annals of Nuclear Energy, 68:234–238.
Kasesaz, Y., Rahmani, F., and Khalafi, H. (2015). Investigation on the reflector/moderator geometry and its effect on the neutron beam design in BNCT. Applied Radiation and Isotopes, 106:34–37.
Kiger III, W., Sakamoto, S., and Harling, O. (1999). Neutronic design of a fission converter-based epithermal neutron beam for neutron capture therapy. Nuclear Science and Engineering, 131(1):1–22.
Koivunoro, H., Bleuel, D., Nastasi, U., et al. (2004). BNCT dose distribution in liver with epithermal D–D and D–T fusion-based neutron beams. Applied Radiation and Isotopes, 61(5):853–859.
Masoudi, S. F., Ghiasi, H., Harif, M., et al. (2018). An electron linac-based system for BNCT of shallow tumors. Radiation Physics and Chemistry, 148:106–111.
Masoudi, S. F. and Rasouli, F. S. (2015). Investigating a multi-purpose target for electron linac based photoneutron sources for BNCT of deep-seated tumors. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 356:146–153.
Pazirandeh, A., Torkamani, A., and Taheri, A. (2011). Design and simulation of a neutron source based on an electron linear accelerator for BNCT of skin melanoma. Applied Radiation and Isotopes, 69(5):749–755.
Rahmani, F. and Shahriari, M. (2011). 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, 38(2-3):404–409.
Rasouli, F. S. and Masoudi, S. F. (2012). Design and optimization of a beam shaping assembly for BNCT based on D–T neutron generator and dose evaluation using a simulated head phantom. Applied Radiation and Isotopes, 70(12):2755–2762.
Rasouli, F. S., Masoudi, S. F., and Kasesaz, Y. (2012). Design of a model for BSA to meet free beam parameters for BNCT based on multiplier system for D–T neutron source. Annals of Nuclear Energy, 39(1):18–25.
Torabi, F., Masoudi, S. F., and Rahmani, F. (2013). Photoneutron production by a 25 MeV electron linac for BNCT application. Annals of Nuclear Energy, 54:192–196.
Torabi, F., Masoudi, S. F., Rahmani, F., et al. (2014). BSA optimization and dosimetric assessment for an electron linac based BNCT of deep-seated brain tumors. Journal of Radioanalytical and Nuclear Chemistry, 300(3):1167–1174.
Yue, G., Chen, J., and Song, R. (1997). Study of boron neutron capture therapy used neutron source with protons bombarding a thick target. Medical Physics, 24(6):851–855.