Abstract
There are two problems in the application of Auger electrons derived from 125IUdR for cancer treatment. One is cell cycle dependency (effective only for S phase cells), the other is side effects for the cell renewal systems(e. g. bone marrow, intestine). We tried intratumoral injection of 125IUdR oil suspension using Ehrlich ascites tumors in the thighs of mice. Oil suspension was more effective in tumor growth delay than saline solution. Single injection of oil suspension at the dose of 0.46 MBq resulted in 21.5 days growth delay while 1.85 MBq of saline solution resulted in 11.5 days growth delay relative to control growth delay. At 40 days after treatment, higher radioactivities were observed in the tumor and the skin of the mice treated with oil suspension, which represented prolongation of 125IUdR oil suspension within the tumors. No normal tissue toxicities were observed. This method can be a new treatment for brain tumors and radioresistant head and neck tumors by further improvements of drug delivery systems
