Medical Radiology and Radiation Safety. 2017. Vol. 62. No. 3. P. 33-41

DOI: 10.12737/article_5927f40e8f1b58.14975996

Photoneutrons for Radiation Therapy

Yu.A. Kurachenko1, Yu.G. Zabaryansky2, E.A. Onischuk3

1. Obninsk Institute for Nuclear Power Engineering, NRNU «MEPhI», Obninsk, Russia, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. ; 2. A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia; 3. National Research Nuclear University «MEPhI», Moscow

Yu.A. Kurachenko - INPE Chief Researcher, Dr. Sc. Phys.-Math. Prof.; Yu.G. Zabaryansky - IPPE Postgraduate Student; H.A. Onischuk - MRRC Junior Researcher, MEPhI Postgraduate Student


Purpose: Show the possibility of neutron therapy with the photoneutron beam produced by the high-power electron accelerator target, when ensuring the required dose in the tumor in a reasonable exposure time and with minimum exposure of normal tissues.

Material and methods: Generation of neutrons from the target of electron accelerator takes place in two stages: eγn, and in the selected electron energy range of 20-100 MeV, the bremsstrahlung yield in many times (~3 orders of magnitude) more than “useful” neutron yield. This raises the problem of the selective control “harmful” for photon radiotherapy at the minimum attenuation of the neutron flux in the extracted beam. In order to solve the general problem of the formation of a neutron beam with necessary spectral characteristics and of sufficient intensity a number of computational tasks of the selection optimal configuration of the output beam unit and its composition was resolved. Particular attention is paid to minimizing additional irradiation of the patient from the bremsstrahlung (generated by electrons) and secondary gamma radiation (generated by neutrons) from the accelerator target as well as from materials of the output unit.

Results: The resulting configuration of the output unit provides the required beam quality in relation to the tasks of the neutron capture therapy (NCT), which is the only competitive technology of neutron therapy on the background of the massive invasion of proton therapy and other high-selective techniques that discriminately damage the target with minimal irradiation surrounding tissues and organs. For the accessible accelerator (average current 4 mA and electron energy 35 MeV) the flux density of epithermal photoneutrons (they required for NCT) in the beam at the output is an order of magnitude or higher than typical ones for existing and planned reactor beams.

Conclusion: The proposed scheme of generation and extraction of photoneutrons for NCT has a number of obvious advantages over traditional techniques:

  1. a) the use of electron accelerators for neutron production is much safer and cheaper than the use of conventional reactor beams;
  2. b) the accelerator with the target, the beam output unit with the necessary equipment and tooling can be placed on the territory of the clinic without any problems;
  3. c) the proposed target - liquid gallium, which also serves as a coolant, is an environmentally friendly material: its activation is very low and rapidly (in ~ 4 days) falls to the background level.

Key words: electron accelerator, tungsten-gallium target, bremsstrahlung, photoneutrons, neutron capture therapy, optimization of beam characteristics


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For citation: Kurachenko YuA, Zabaryansky YuG, Onischuk EA. Photoneutrons for Radiation Therapy. Medical Radiology and Radiation Safety. 2017;62(3):33-41. Russian. DOI: 10.12737/article_5927f40e8f1b58.14975996

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