To the Editor.—The September 1966, issue of the Journal carries a report by David et al of the Gelisinger Medical Center on their attempts to determine and localize intracranial disease in childhood by the use of brain scans. A group of 220 children were given 100μc to 500μc of radioactive mercury. The report does not give the indications for using the test, but states that scans were done on 113 of 231 children with a final diagnosis of convulsive disorder; the scan was abnormal in two of them, but it is not mentioned whether these two had a mass lesion.
In nine children in whom a tumor was subsequently found, the scan was negative in three, and positive or suspicious in six. This is a 33% rate of false-negative results, and clearly indicates that brain scan alone cannot satisfactorily rule out the presence of a brain tumor. Of the