[Blood picture changes in rats after 90Y-citrate administration].

Therapeutic doses of 90Y-citrate show a high selective accumulation in bone. Bone marrow is the critical organ. Investigations in rats show a decrease of leucocytes, erythrocytes and thrombocytes depending on dose. A significant decrease of the leucocytes and thrombocytes was seen with 0.5 mCi (17.5 MBq) 90Y per kg bodyweight, with 2.0 mCi (74 MBq) also of the erythrocytes. This would be equivalent to a dose of 35 to 140 mCi (1.295 to 5.18 GBq) for a normal patient (70 kg). Therefore, a single dose of 10 mCi (370 MBq) of 90Y-citrate should be tolerated by a tumor patient without any blood cell depression, if there was no prior chemotherapy.