International Journal of Radiation Research, October 2013 Volume 11, No 4 Optimised BNCT facility based on a compact D-D neutron generator INTRODUCTION Glioblastoma multiforme (GBM), is by far the most common and most malignant of the glial tumors. This type of tumor is extremely difϐicult to eliminate by surgery owing to its ϐinger‐like extensions that inϐiltrate the surrounding normal brain tissue (1, 2) . Thermal and epithermal neutrons play an important role in the efϐiciency of Boron Neutron Capture Therapy (BNCT). While thermal neutrons can easily reach cancers which are located at near‐tissue‐surface, epithermal neutrons is requested to treat deep seated tumors. Cancer cells are killed by α particles and 7 Li nuclei produced through the 10 B (n, α) 7 Li reaction. The 7 Li and α particle have a range 4.1 and 7.1 μm, which is less than the diameter of a cell nucleus. The chances are high that at least one of the nearby malignant cells will be destroyed (3‐5) . The BNCT facilities that are currently operating are based on nuclear reactors. Nuclear reactors provide high‐intensity neutron beams and reduce signiϐicant the treatment time (6, 7) . However, nuclear reactors are very expensive and too large to be used in hospitals. In addition the main questions about the nuclear reactors are the safety and authorization concerns that prevent its installation in a hospital environment J.G. Fantidis * , E. Saitioti, D.V. Bandekas, N. Vordos Department of Electrical Engineering, Kavala Institute of Technology, Greece ABSTRACT Background: Boron Neutron Capture Therapy (BNCT) is a very promising treatment for paƟents suffering gliobastoma mulƟforme, an aggressive type of brain cancer, where convenƟonal radiaƟon therapies fail. Thermal neutrons are suitable for the direct treatment of cancers which are located at near‐Ɵssue‐surface; deep‐seated tumors need harder, epithermal neutron energy spectra. Materials and Methods: In this work a BNCT facility based on a compact D–D neutron generator, has been simulated using the MCNP4B Monte Carlo code. The materials considered, for the design of the facility, were chosen according to the EU DirecƟve 2002/95/EC, hence, excluded the use of cadmium and lead. Results: An extensive set of calculaƟons performed with MCNP4B Mote Carlo code have show that the combinaƟon of TiF 3 which integrates a conic part made of D 2 O, then followed by a TiF 3 layer is the opƟmum moderator design. The use of BiF 3 as spectrum shiŌer and γ rays filter, Titanium as fast neutron filter and Lithium as thermal neutron filter is necessary in order to obtain an epithermal neutron beam with high quality. Conclusion: The simulaƟons show that, even if the neutron flux is below the recommended value for clinical treatment, the proposed facility is a good alternaƟve for clinics which cannot afford to build and maintain a small nuclear reactor. Keywords: Boron neutron capture therapy, epithermal neutron, MCNP4B, D–D neutron generator, ROHS directive. *Corresponding author: Dr. Jacob G. Fantidis, Fax: +30 2510 462315 E‐mail: fantidis@yahoo.gr Received: July 2012 Accepted: April 2013 Int. J. Radiat. Res., October 2013; 11(4): 207-214 ► Original article