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Stabilizer Reaction-Free 99m Tc-Sulfur Suspension for Liver, Spleen, and Bone-Marrow Scanning

1969; Radiological Society of North America; Volume: 92; Issue: 1 Linguagem: Inglês

10.1148/92.1.170

1527-1315

Milo M. Webber, Winona Victery, Michael D. Cragin,

Radiopharmaceutical Chemistry and Applications

Technetium-99m-sulfur suspension produced by heating of thiosulfate was introduced for clinical use by Patton et al. in 1965(1). At present it is employed extensively for demonstration of liver, spleen, and bone marrow. The original preparation, technetium sulfide-sulfur “colloid,” was co-precipitated with rhenium sulfide and stabilized by the addition of gelatin. Larson and Nelp (2) suggested an alternative preparation of this colloid which was stabilized with dextran instead of with gelatin. After an initial period of using gelatin, dextran was employed at this institution. Over a period of several months it was noted that of several hundred patients, three had reactions of the anaphylactoid type manifested by flushing of the skin and hypotension. Investigation of these symptoms and a review of the literature indicated that this was most likely related to the dextran. This has been confirmed by others (3). As a result of these reactions, the preparation of the colloid was modified by eliminating the dextran. It was found that the material was satisfactory for a liver scan although it contained no stabilizer. The use of rhenium was also dropped, leaving no adverse effect on the general clinical utility of the preparation. Several months passed during which the colloid was used in this manner. No reactions of any type were associated with its use. However, with new samples of reagents, it was noted that some variability of the preparation developed with an increase in the amount of free pertechnetate. It was therefore decided to carefully study the preparation of the material to determine the optimum proportions of reagents required to obtain the highest onsistent recovery of technetium sulfur suspension and to determine its stability. Methods The reagents used for preparation of technetium sulfur suspension are: a. One normal hydrochloric acid b. Sodium thiosulfate, 10 mg per cc c. Phosphate buffer at pH 7.4 consisting of 15.26 per cent Na2HPO4·7H20 and 0.92 per cent NaH2PO4·H20 All are prepared with sterile, pyrogen-free water and are sterilized by Millipore filtration. Into a dry, sterile vial is placed 3.5 cc pertechnetate in saline from a molybdenum technetium-99m generator, 1 cc of the above thiosulfate solution, and 1 cc IN HCl. The vial is vented with a 23-gauge needle and placed in a 100° C water bath for three and one-half minutes, after which it is cooled three and one-half minutes in cold running water. Two cubic centimeters ofphosphate buffer are added with gentle mixing. The amount of soluble pertechnetate present is determined by measuring the activity per gram in the deep-well scintillation counter before and after Millipore filtration (0.3 microns). The yield was calculated as being equal to 100 per cent minus the ratio of the activity per gram following filtration divided by activity per gram before filtration. In addition, each colloid preparation was routinely checked by microscopic examination with X430 magnification. A drop of the material was placed in a hemacytometer chamber in which the number of particles and aggregates per mm3 was counted.