Evaluation of ^99mTc-Labeled Amino Acids as Radiopharmaceuticals. III. ^99mTc Complexes of Ligands related to Ethylenediamine-N, N-diacetic Acid for Tumor Visualization

Abstract

Seventeen ^99mTc-labeled ligands were evaluated as tumor scanning agents by preparing sequential scintigrams of mice bearing intramuscularly transplanted Ehrlich tumor. The ligands were labeled by the SnCl₂ method and were administered intravenously to the mice. The ligands studied were ethylenediamine-N, N-diacetic acid (u-EDDA) and structurally related compounds. ^99mTc complexes of u-EDDA, ethylenediamine-N, N'-diacetic acid, N-hydroxyethyliminodiacetic acid, and propylene-1, 3-diamine-N, N-diacetic acid achieved clear visualization of Ehrlich tumors. The image of the tumor was less clearly visualized with the complexes of iminodiacetic acid, N-methyliminodiacetic acid, nitrilotriacetic acid, ethylenediamine-N, N, N, ', N'-tetraacetic acid, N-hydroxyethylethylenediamine-N, N, ', N'-triacetic acid, hydrazine-N, N-diacetic acid, and 3-oxopiperazine-1-acetic acid.