Comparative evaluation of 201Tl SPECT and CT in the follow-up of irradiated brain tumors.

Radiation-induced changes in post-irradiated brain tumors may produce morphological alterations similar to those of tumor recurrence on computed tomography (CT). However, 201Tl single-photon-emission computed tomography (SPECT), with its ability to image metabolic changes, may differentiate post-irradiated gliotic changes from metabolically active congregations of viable tumor cells. This study was carried out to compare these two imaging modalities for the follow-up evaluation of post-irradiated brain tumors.