THALLIUM AVID CEREBRAL RADIATION NECROSIS

Thallium imaging has been proposed as a noninvasive method to distingu ish recurrent tumor from cerebral radiation necrosis in patients who h ave undergone radiation therapy. Previous reports have supported the i ntuitive hypothesis that metabolically active tumor tissue would accum ulate Tl-201 to a much higher degree than nonviable necrotic tissue. A case of biopsy-proven cerebral radiation necrosis is presented demons trating a degree of Tl-201 avidity previously thought to be diagnostic of recurrent tumor. Based on this finding, it is concluded that a hig h degree of Tl-201 uptake does not exclude the diagnosis of cerebral r adiation necrosis.