Preparation of dextran 70 injection labeled with technetium 99m for use as a cardiac blood-pool imaging agent

A means of compounding dextran 70 injection labeled with technetium Tc 99m by using readily available pharmaceutical components is described, and the compound's biological distribution is evaluated. The radiopharmaceutical was prepared by mixing 10 mg (0.17 mL) of dextran 70 in sodium chloride with 0.33 mL of 0.9% sodium chloride injection in a 1-mL syringe. This solution was added to a sterile, pyrogen-free vial containing stannous chloride, and the steps were repeated until five vials had been prepared. The contents of each vial were mixed by swirling until the solids were dissolved. The mixture was incubated for five minutes at 22 degrees C, then 1.48 gigabecquerels of sodium pertechnetate Tc 99m injection in a volume of 0.5 mL was added to each vial. The final mixture was incubated for 15 minutes at 22 degrees C and then stored at room temperature. Thin-layer chromatography was performed after zero, three, and six hours of storage to assess radiochemical purity. Five more vials were prepared as above, and five male volunteers were given 185 megabecquerels of the radiopharmaceutical by i.v. push, and scintigraphic images of the anterior chest were taken immediately and 1, 2, and 24 hours after injection. Immediately after preparation, a mean +/- S.D. of 99.0 +/- 1.0% of the 99mTc was bound to dextran 70. Mean +/- S.D. binding was 98.1 +/- 3.7% and 95.8 +/- 7.5% at three and six hours, respectively. Scintigraphy in the five volunteers yielded high-contrast images of the cardiac blood pool with little uptake of the radionuclide by the lungs. (ABSTRACT TRUNCATED AT 250 WORDS)