Radiotherapy of cancer has been a subject to get significant notice for clinical and research interest after the discovery of neutron. For instance, radiotherapy using fast neutron beam for the destruction of tumors cell is emerging as a promising technique on the basis of recent research data. Nowadays, neutron capture therapy (NCT) which is a somewhat different form of neutron-based therapy proposed by Locher in 1936 and particularly for intracranial tumors is proposed by Sweet in 1951. In NCT, a neutron captured agent called yielding boron NCT has been guided into the malignant tissue, and after that, at a suitable time, the boron NCT is exposed by thermal neutrons generated by either an external neutron beam producer or a suitable nuclear-based accelerator. These thermal or high energetic neutrons interact with the boron NCT, which is actually present inside the malignant cells and generates highly energetic alpha particles and lithium ions within the cells which leads to their destruction by damaging its DNA itself.

The United States was the first country to take human trials of BNCT for brain tumors in 1967. However, there were insufficient supporting technologies available at that time which made it unsuccessful. However, some research group in Japan continued their work on NCT and got some promising results. With the passage of time, the required technologies for BNCT have improved, resulting in a resurgence of interest worldwide. Recently, Japan, the United States, and Europe have given the emphasis on the production of higher energy epithermal neutron beams, which helps in generating neutron flux at depth. So, with the inclusion of newer facilities which also features epithermal neutron beam has given motivation to researchers to conduct more trials of BNCT on human. These trials are ongoing at ‘Brookhaven National Laboratory‘ (BNL) and ‘Massachusetts Institute of Technology (MIT)’ in the United States. These days MIT trials are based on the primary and metastatic treatment of brain tumors that uses the basic principle of Physics and biophysics of neutron capture theory. These trials have been performed by MIT & Harvard University.

Results obtained from these trials using epithermal-neutron BNCT have been inspiring so far, particularly with regard to human safety. In addition to this, medically significant improvement in tumor cell destruction by using BNCT has also been observed. However, in all the case studies, a conclusive statistical resilient of improvement in tumor patient survival compared to standard treatments remains to be established. Furthermore, the beginning of additional epithermal neutron trials with other advanced facilities is expected in the near future.