Localization of Intracranial Vascular Lesions by Radioactive Isotopes and an Automatic Contour Brain Scanner

D URING the past ten years, more than 100 reports in the neurosurgical and nucleonic l i terature have indicated tha t radioactive isotopes can provide a useful, painless and safe me thod for the detection and localization of certain intracranial lesions. Most authors have agreed tha t meningiomas, mal ignant gliomas, and meta static neoplasms are readily and sometimes strikingly detected. The degree of success obtained in localizing other types of tumour and a wide var ie ty of non-neoplast ic lesions has var ied considerably among these reports. In this area, it appears t ha t the use of an appropr ia te radioact ive substance, a satisfactory technique for scanning the head, as well as suitable devices for discriminating and comput ing the result ing radiat ion, m a y make all the difference between success and failure?.5.15.2~ The reports, for example, on the localization of subdural h a e m a t o m a s b y the isotope method will serve to indicate this variabil i ty. Using diiodofluorescein Moore 13 found an increased concentrat ion in one case of subdural haematoma, a l though the mater ia l removed at operation proved to contain very little of the radioisotope, and he suggested tha t the increased rate of count over the side of the subdural h a e m a t o m a migh t be ascribable to edema of the brain. Wi th the same isotope Peyton and others ~4 also detected subdural haematomas , bu t Ashkenazy et al? in 8 subdural h a e m a t o m a s found little or no evidence of localization.