Possibilities and Limitations of Scintigraphy on Meningiomas

Abstract

Meningiomas can be detected with greater certainty than other brain tumors by means of nearly all the radioisotopes currently used in tumor diagnosis. Evidently, their good detection is due to strong vascularization of meningiomas. Therefore, isotope compounds such _J131-albumin (RIHSA) and Tc^99m, which stay in the blood stream over a period of time, offer especially favourable conditions for detecting meningiomas. Clinical experience however shows that equally satisfactory results,can be obtained with radioactive compounds, which remain only briefly in the blood stream and are quickly metabolized such as Hg compounds (Hgl and Hg), Bi²⁰⁶ and positron radiations As⁷⁴, Cu⁶⁴ and Ga⁶⁸ (Fig. 1). A synopsis of ample statistical studies shows that most isotopes are able to detect over 90 % of the meningiomas with varying degrees of localization. The relatively poor results in using Hg197 and Cu64 are probably attributable to insufficient methods and equipment. We observed no essential difference in the diagnostic exactness of As⁷⁴ and Cu⁶⁴, taking into account the different impulse outputs due to another radiation quality. Compounds remaining in the blood stream for a long time are obliged to exclude activity originating from voluminous cerebral sinuses, so that small tumors and those next to a sinus may be overlooked.