[Decreased tumor viability of gliomas after radiation therapy, evaluated by dynamic CT scan]

The tumor viability of 28 gliomas after radiation therapy has been investigated by dynamic CT scan that estimated 4 parameters (Area, Peak, Time of Peak, and, Height of Plateau) from a time-density curve. Glioblastoma showed higher values of Area and Peak, whereas astrocytomas showed lower values when compared to those found in normal gray matter. After radiation therapy, the Area and Peak decreased and the Time to Peak was prolonged, suggesting a decrease in blood volume and blood flow in the tumor tissue. The increased Height of Plateau showed an increased permeability of the tumor-vessels. These results suggest that a dynamic CT scan provides a useful indicator of the change in tumor-viability after radiation therapy.