Tc 99m Pertechnetate for Brain Scanning
1965; Radiological Society of North America; Volume: 84; Issue: 2 Linguagem: Inglês
10.1148/84.2.354
ISSN1527-1315
Autores Tópico(s)Advanced Radiotherapy Techniques
ResumoBrain scanning is an important tool in the diagnosis of intracranial disease. With Hg203 and Hg197 as chlormerodrin, the scans are nucleographically positive in a variety of intracranial abnormalities including meningioma, primary and metastatic cerebral neoplasia, cerebral infarct, and arteriovenous malformation. The purpose of this communication is to illustrate their positive quality, with use of a new scanning agent Tc99m-sodium pertechnetate. The tumor-to-brain ratio of Tc99m-pertechnetate in mouse ependymoma is 22, a value similar to that of the radiomercurial compounds (1). The availability of short-lived radionuclide generators in clinical nuclear medicine laboratories has been a significant advance in diagnostic brain scanning (2, 3). Because of the shorter physical half-life of these nuclides, larger doses can be administered to the patient achieving: 1. Greater counting rates, and thereby improved counting statistics 2. Faster scanning speeds, because of the improved counting rate 3. Reduced patient irradiation. Tc99m, the daughter decay product of Mo99, has a physical half-life of six hours, a gamma emission of 140 Kev (98 per cent), 142 Kev (2 per cent), Eβ 0.014, and i Γ of 0.56. Total-body irradiation from an intravenous dose of 10 millicuries of Tc99m in a 60 kg man 170 cm tall is 141 millirads. The thyroid radiation from this dose is approximately 5.5 rads. The material is obtained by eluting the Mo99 generator with 0.1 N HCl and adjusting the pH of the eluent to 5.5 thereby precipitating the Al(OH)3 contained in the generator. The material is then filtered, sterilized, and assayed and is ready for injection.
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