Clinical experience of boron neutron capture therapy for patients with malignant brain tumour using BSH

Boron neutron capture therapy (BNCT) has been studied using a combination of thermal neutron and Sodium borocaptate - BSH (Na2B12H11SH) in Japan since 1968. On the day of BNCT, about twelve hours before neutron irradiation, BSH is diluted in 500 ml of saline and given by drip intravenous infusion (60 ∼ 80 mg BSH/kg body weight). At the beginning of the project, BSH was directly injected into the carotid or vertebral artery of some patients. To clarify the relationship between the radiation dose, histological grading and clinical outcome, we retrospectively analysed the outcome for 105 patients, with glial tumours, treated between 1977 to 1997. Six patients out of 105 lived more than 10 years after BNCT. The estimated tumour volume radiation dose in the group was 18.2 ± 3.3Gy. It was 12.4 ± 3.5Gy in 11 patients who lived more than 5 years. In the patients who lived more than 3 years (n=29 patients) the dose to the minimum tumour volume was 11.5Gy in grade 2, 15.6Gy in grade 3 and 18.2Gy in grade 4 gliomas. On the other hand they were 6.7Gy in grade 2, 11.8 Gy in grade 3. and 9.8Gy in grade 4 in patients (n=76) who lived less than 3 years. Radiation necrosis was found in 19 patients (19/183 10.4%). The maximum vascular radiation dose of the patients with necrosis was 21± 8.1 Gy, while it was 9.4 ± 5.1 Gy without radiation necrosis. According to the data, we have made new protocol using epithermal neutrons and BSH. The outcomes for fifteen patients with glioblastoma, who were treated by the new protocol using a new mode composed of thermal and epithermal neutrons are reported