CONCENTRATION OF RARE-EARTH ELEMENTS, AS, AND TH IN HUMAN BRAIN AND BRAIN-TUMORS, DETERMINED BY NEUTRON-ACTIVATION ANALYSIS

Toxic elements As and Th, six rare-earth elemental profiles of brain t umor tissues from 16 patients of astrocytomas (grade I-III), and norma l human brain tissues of 18 male, age-matched autopsies serving as con trols have been studied by radiochemical neutron activation analysis. P-204 [di(2-ethylhexyl) phosphate] extraction chromatography column wa s used for group separation of rare-earth element (REE) by one step. C ompared with the normal brain tissues, the analytical results showed t hat the concentrations of Th, La, Ce, Gd, and Lu were significantly hi gher in tumor tissues (P <0.01 or 0.001). The possible effects of REE on tumor cell were discussed.