Serial CT studies performed for 1 year on a female patient suffering from a pinealoma are reported. Under cobalt therapy (5000 rads) a remission of the pinealoma was achieved. A short time later, metastases developed and cobalt therapy was repeated (6000 rads). Rapid tumor remission was seen again, but rapid occurrence of probable metastases too. The question whether radionecrosis or metastases were present cannot be answered.