Use of Radioactive Diiodofluorescein in the Diagnosis and Localization of Brain Tumors

Abstract

Diiodofluorescein (DIF) was synthesized to contain I131, the amt. of I131 added being adjusted to give 1 milli-curie radioactivity/10 ml. of a 2% soln. of the final product, sodium DIF. An amt. of dye containing 500-600 millicuries of radioactivity was injd. intraven. in each case. Increasing volumes were injd. as the I131 decayed. There were no toxic reactions. Counts were obtained by a Geiger-Muller tube, and were taken for 3- to 5-min. intervals at each of several positions on the skull with the cone of the detection unit directly on the skin. Although counting was begun directly after injn., differential readings between areas over the suspected tumor and symmetrical control areas appeared only after 2-4 hrs. 15 patients with suspected brain tumors were subjected to this technic. Correct diagnoses of negative findings, as well as positive, have been made. An area could be outlined on the skull over the tumor site which corresponded with the extent of the superficially situated meningeoma found at operation. The limitations of the method are unknown and its usefulness is still to be detd. In mice brain tumors, the concn. of dye in the tumor was as high as 80 times that in the normal areas.