Distribution of thermal neutron dose in nodular melanoma. Preclinical test by using animals and analysis of human clinical data

There is the thermal neutron capture therapy that uses the thermal neutrons from nuclear reactors for the radiation treatment of malignant tumors, and because it can irradiate high LET radiation in large amount limiting to diseased parts, now the clinical research is in progress as an effective treatment. In the case of malignant melanoma, boron neutron capture treatment was attempted in 18 cases so far, and the local suppression was obtained in most cases. Recently, nodular melanoma was treated by the BNCT, but it was very difficult to forecast the dose distribution inside a tumor. The data on the thermal neutron dose distribution in this human case was compared with the preclinical test on the pig having spontaneous melanoma, and the countermeasures of hereafter were investigated. The objects and the methods of the preclinical test and the human medical irradiation, and the results of dose distribution in both cases and the countermeasures to nodular melanoma are reported. The factors that exert influence to the dose in depth are pointed out. (K.I.)