Basic requirements and parameter optimization for boron neutron capture therapy of extracorporeal irradiated and auto-transplanted organs

BackgroundIn 2001 and 2003, at the University of Pavia, Italy, boron neutron capture therapy (BNCT) has been successfully used in the treatment of hepatic colorectal metastases (Pinelli et al., 2002 and Zonta et al., 2006). The treatment procedure (TAOrMINA protocol) is characterised by the auto-transplantation and extracorporeal irradiation of the liver using a thermal neutron beam.MethodsThe clinical use of this approach requires well founded data and an optimized irradiation facility. In order to start with this work and to decide upon its feasibility at the research reactor TRIGA Mainz, basic data and requirements have been considered (Wortmann, 2008). Computer calculations using the ATTILA (Transpire Inc. 2006) and MCNP (LANL, 2005) codes have been performed, including data from conventional radiation therapy, from the TAOrMINA approach, resulting in reasonable estimations.ResultsBasic data and requirements and optimal parameters have been worked out, especially for use at an optimized TRIGA irradiation facility (Wortmann, 2008). Advantages of the extracorporeal irradiation with auto-transplantation and the potential of an optimized irradiation facility could be identified. Within the requirements, turning the explanted organ over by 180° appears preferable to a whole side source, similar to a permanent rotation of the organ.ConclusionsThe design study and the parameter optimization confirm the potential of this approach to treat metastases in explanted organs. The results do not represent actual treatment data but a first estimation. Although all specific values refer to the TRIGA Mainz, they may act as a useful guide for other types of neutron sources. The recommended modifications (Wortmann, 2008) show the suitability of TRIGA reactors as a radiation source for BNCT of extracorporeal irradiated and auto-transplanted organs.

► The approach to treat metastases in explanted organs allows for more specific optimization.
► A modified TRIGA as a neutron source can achieve promising results in short irradiation times.
► Turning the organ in the beam leads to a better dose distribution than rotation and all side source.
► The additional risk for the patient seems to be justified due to the potential therapeutic benefit.
► The feasibility for the application of the treatment as a standard method is considered to be good.