An Optimum Source Neutron Spectrum and Holder Shape for Extra-Corporal Treatment of Liver Cancer by BNCT

In extra-corporal treatment of liver cancer by BNCT, it is desired to have an as homogeneous as possible thermal neutron field throughout the organ. Previous work has shown that when using an epithermal neutron beam, the shape of the holder in which the liver is placed is the critical factor. This study develops the notion further as to what is the optimum neutron spectrum to perform such treatments. In the design calculations, when using Monte Carlo techniques, it is shown that when the expected contributions of the source neutrons in every part of the liver is calculated, a linear optimization scheme such as the Simplex method results in a mix of thermal and epithermal source neutrons to get the highest homogeneity for the thermal neutron field. This optimisation method is demonstrated in 3 holder shapes: cuboid, cylindrical and spherical with each 3 volumes of 2, 4 and 6 litres. A 10 cm thick cuboid model, irradiated from both sides gives the highest homogeneity. The spherical (rotating) holder has the lowest homogeneity but the highest contribution of every source neutron to the thermal neutrons in the liver. This can be advantageous when using a relatively small sized neutron beam with a low strength.

MOSS Raymond;  SAUERWEIN Wolfgang;  MALAGO Massimo;  KLOOSTERMAN Jan Leen;  VAN DER HAGEN Tim;  VAN DAM Hugo; 

NIEVAART Victor Alexander; 

2006-11-17

International Society for Neutron Capture Therapy: ISNCT

JRC35078

https://publications.jrc.ec.europa.eu/repository/handle/JRC35078,