Objectives Boron neutron capture therapy (BNCT) is one of the radiation therapies known to have a selective lethal effect on tumor cells. Thermal neutrons are captured by the 10B atom, resulting in the emission of linear recoiling Alfa particles and 7Li nuclei, with traveling ranges of ∼9 and ∼5 micrometers respectively. These particles are high linear energy transfer (LET) radiation and lethally damage DNA. BNCT for cutaneous melanoma, using 10B-para-boronophe-nylalanine (BPA) as the boron delivery agent, was developed and successful BNCT treatment of 18 melanoma patients has been reported by Mishima et al. Methods Based on their treatment regimen and with the approval of the Nuclear Safety Bureau of the Japanese government and the Medical Ethics Committees of Kawasaki Medical School and Kyoto University, we have conducted BNCT clinical trials on patients with mucosal melanomas in head-and-neck at the Kyoto University Research Reactor (KUR) and the Japan Research Reactor No. 4 (JRR-4) since 2005. Results To date, we have treated 6 patients with mucosal melanomas in the nasal cavity with BNCT. 4 patients showed a complete response (CR) by 6 months and 2 patients showed a partial response (PR) 3 months after BNCT. None of the patients showed any serious damage in normal tissue surrounding tumor site. One patient from this study died due to distant metastasis. However, no local recurrence of melanoma has been observed in all CR patients and no regrowth of melanoma in all PR patients. Conclusions BNCT thus is a promising treatment for achieving local control of mucosal melanomas.
Investigation of deep-seated brain tumor treatment based on Tehran research reactor new boron neutron capture therapy facility
