Therapeutic irradiation of the central nervous system using intrathecal 90Y--DTA.

The erdication of established neuroleukaemia is often difficult, and with subsequent relapses even harder. The use of an intrathecally-injected beta emitting isotope has the advantage of preserving the bone-marrow of the vertebral column and cranium whislt irradiating the meninges. The value of intrathecal 90Y-DTPA(diethylene-triamine penta-acetic acid) has been investigated in nine patients with neuroleukaemia or CNS involvement in malignant lymphoma. Measurements of retention of the isotope in the whole body, spinal, and intracranial subarachnoid spaces have been made, together with blood levels, and are reported. The clinical results are presented. In three out of five evaluable patients 90Y-DTPA failed to maintain a chemotherapy-induced CNS remission and in two out of two evaluable patients malignant cells were not dispersed from the CNS with a single intrathecal injection of 90Y-DTA. It is concluded, therefore, that with this agent and the doses used no useful clinical result is gained.