Early experience in brain tumor localization at this institution, utilizing diiodofluorescein I131 and scintillation counter "spot checking," proved this technique suitable only for screening.1,2 Further progress elsewhere included development of scanning scintillation detectors,3 photographic recording,4,5 and more suitable scanning agents including radiomercury-labeled chlormerodrin (Neohydrin).6 Our present program utilizing the above refinements in equipment and radiomercury-tagged chlormerodrin has proved useful in the localization of intracranial tumors in the majority of cases prior to contrast studies.
The isotope initially used was Hg203 tagged to chlormerodrin. This compound was introduced in 1959 as an agent for brain scanning by Blau and Bender6 who found it significantly better than albumin I131.7 Hg203 decays with a half life of 45.8 days with the emission of a low energy β-particle to an excited state of Tl203, which in turn emits a single 0.28 mev γ-ray.
RHOTON AL, ANNA-MARIE CARLSSON, TER-POGOSSIAN MM. Brain Scanning With Chlormerodrin Hg197 and Chlormerodrin Hg203. Arch Neurol. 1964;10(4):369–375. doi:10.1001/archneur.1964.00460160039003
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