Preparation, quality control and clinical acceptance of labeled Macrotec.

Thirty minutes after reconstitution, radiochemical purity determinations of the lung-scanning agent Macrotec (99m-Tc-MAA) indicated 95-100% technetium labeling: 76% of the particles had a mean diameter of 10-50 mu. Rat tissue distribution studies indicated lung uptake of 98% at 15 minutes. The biological half-life in the lung was 8.3 hours. In 12 patients requiring emergency lung scans, 9 scans were rated excellent. No liver, spleen or thyroid uptake or adverse reactions were noted.