Localization of intracranial tumors.Comparative study with131I-labeled antibody to human fibrinogen and neohydrin-203Hg

Two of the most promising isotopically labeled compounds for the localization of intracranial tumors by photoscanning are compared. 203Hg-neohydrin and 131I-labeled antibody to human fibrinogen are equal in effectiveness in localizing known tumors in the cranium, and they introduce approximately the same proportion of false information. 203Hg-neohydrin is more convenient: it is commercially available. Furthermore, scans can be performed as early as four hours after its administration, whereas an interval of at least 40 hours is necessary following the administration of 131I-labeled antibody before scanning can be efficiently undertaken, because of the slow clearance of this agent from the blood. A 44 to 48 hour interval was used for 131I-labeled antibody in this study. 131I-antibody is effective for detecting tumors outside the cranium. For tumors inside the cranium this localization technique with either agent has been found to be extremely useful in neurosurgical care.