“…The possibilities and limitations of the intracavitary implantation of radioisotopes into craniopharyngioma cysts have been documented in the last two decades. [3,8,13,17,33] Radioisotopes emitting short-range beta radiation and with a short half-life Na 32 [4,6,12,21,23] 90 YCl 3 , [7] and later with 90 Y-silicate colloid [2,3,10,[15][16][17][18][19]24,27,34,35,38,44,52] or 186 rhenium [34][35][36]43,48,52] have all been used.…”