Johannes F. Klopper

Evaluation of 99mTc-DTPA Prepared by Three Different Methods

Abstract Comparison of the biological behavior of three compounds containing DTPA and technetium 99m shows that only two of these compounds are true chelates. The third compound, produced with a kit (Renotec), is similar in behavior to that of the renal scanning agent 99mTc-Fe-ascorbic acid.

Vascular Imaging with 99mTc-Red Blood Cells1

99mTc can be firmly labeled to erythrocytes and used for vascular pool imaging in this form. Since large amounts of activity can be administered, some of the peripheral vessels can be visualized with good resolution. The technique may be useful for investigation of arteriosclerotic vascular disease.

Vascular imaging with 99m Tc-red blood cells.

99mTc can be firmly labeled to erythrocytes and used for vascular pool imaging in this form. Since large amounts of activity can be administered, some of the peripheral vessels can be visualized with good resolution. The technique may be useful for investigation of arteriosclerotic vascular disease.

Effect of Carrier on Organ Distribution of 75Se-Selenomethionine

Abstract 75 Se-selenomethionine was the first amino acid used in clinical scintillation scanning. It can be produced with a high specific activity by biosynthesis (specific activity about 300 mCi/mg) or chemical synthesis (specific activity about 6 mCi/mg). Synthetic methods have been developed recently for the incorporation of the short-lived radionuclides carbon-11 and fluorine-18 into organic molecules. The final products of these syntheses have, however, relatively low specific activities (about 1.0 μCi/mg). This made it important to study the effect of carrier on the organ distribution of labeled organic compounds. For that purpose, mice were injected with 75 Se-selenomethionine, with varying amounts of d,l-methioine, d,l-selenomethionine, and l-methionine added. With increasing amounts of selenomethionine carrier there was a decrease of uptake to a maximum of 50% in all organs, while with methionine as carrier the liver uptake increased. As a result, selenomethionine carrier, unlike methionine, does not cause a decrease in the ratios of pancreas/liver concentration. The fact that methionine and selenomethionine follow separate pathways is significant for external visualization. It indicates that radioactive organic compounds of low specific activity may be useful for clinical scintigraphy, as long as one can ensure that the nonradioactive carrier is identical to the labeled compound.