Brachytherapy of subarachnoid space and brain ventricles with radiocolloid phosphate chromic 32p (CROP)

A method of brachytherapy of the CNS with Chromic Phosfate (32P) in colloidal form (CROP) introduced in the subarachnoid space was developed. 90 rabbits were used and colloids were injected through a cysternal tap The permanence and uniform distribution of the colloid in the pio-arachnoid membrane along the whole subarachnoidal space and ventricular ependyma was asserted with autoradiographs and histological sections with stripping film techniques. The distribution of 32P in liver (10%), spleen (7%) and bone marrow (2%) and other organs has no significant effects. The perfect tolerance to the injection of colloids of fine particles with less than 100 nm, (CROP) was proved and no severe neurotoxic effects where observed. When colloids with particles larger than 100 nm were used this undesirable effects were seen. With very high doses, no edema nor lesions could be demonstrated in histological studies of nervous cells or nervous tissue. Up to 6 months the animals did not present neurological symptoms attributable to CROP in that period, even with repeated applications (Au)