Title: Detection and quantitation of left-to-right shunting by iridium-191m angiography
Abstract: An osmium-191..-->..iridium-191m radionuclide generator suitable for first-pass angiography has been developed. Osmium-191 with a physical half-life of 15.4 days is produced in the reactor by the /sup 190/Os(eta, ..gamma..)/sup 191/Os reaction and decays by internal conversion to /sup 191/Ir/sup m/. Iridium-191m has a physical half-life of 4.96 s and decays by isometric transition to stable /sup 191/Ir. It emits a gamma ray at 129 keV with 30% abundance. In addition, x-rays at about keV in 58% abundance are emitted as a result of internal conversion from the 129 keV excited state. Osmium-191 metal is converted into potassium osmate, which is loaded into a column of 0.9 m1 of AGMP-1 anion exchange resin. This column is connected in series to another column also of 0.9 m1 of Dowex-2 and pyrocatechol. The generator is eluted with 0.6 to 1 m1 of 0.9% NaCl, pH 1. One m1 of eluant yields 7 to 10% of the /sup 191/Ir/sup m/ in the column and there is a 3 to 5% x 10/sup -3/% of /sup 191/Os breakthrough. The eluant is rapidly diluted and flushed with a buffer solution (25% 0.05M Na/sub 2/HPO/sub 4/, 75% 0.9% NaC1) before injection. The lowest pH delivered is 3.5.more » First-pass radionuclide angiography has been carried out in 59 patients ranging from four days to 67 years of age (mean = 14 years) for detection and quantitation of left-to-right shunting. Twelve patients underwent cardiac catheterizations with simultaneous /sup 191/Ir/sup m/ angiography. They had pulmonary-to-systemic ratios (Qp:Qs) ranging from 1.04 to 3.00. The major advantages of /sup 191/Ir/sup m/ are low radiation dose to patients high photon flux and the possibility of obtaining repeated studies within a short time. 22 refs., 3 figs.« less
Publication Year: 1981
Publication Date: 1981-01-01
Language: en
Type: article
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Cited By Count: 1
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