Preparation and biological evaluation of 99mTc-stannous fluoride colloid-labelled-leucocytes in rats 99mTc-stannous fluoride-labelled-leucocytes in rats

✍ Scribed by C. Tsopelas; E. Smith; P.A. Drew; F.D.L. Bartholomeusz

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: French
• Weight: 122 KB
• Volume: 46
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.715

✦ Synopsis

Abstract

High splenic activity is always visible in ^99m^Tc‐stannous fluoride (SnF~2~)‐labelled‐leucocytes scans. In an attempt to reduce this activity, this study investigated the effect of pre‐injected SnF~2~ colloid on the distribution of ^99m^Tc‐SnF~2~ colloid, ^99m^Tc‐SnF~2~‐labelled‐leucocytes, and opsonized ^99m^Tc‐SnF~2~ colloid in rats. The radiopharmaceuticals ^99m^Tc‐SnF~2~ colloid and ^99m^Tc‐SnF~2~‐leucocytes were each found to exhibit identical biodistributions in separate experiments. SnF~2~ colloid pre‐injection (26 μg) resulted in reduced splenic uptake of ^99m^Tc‐SnF~2~ colloid (38%) and ^99m^Tc‐SnF~2~‐labelled‐leucocytes (30%), but not for opsonized ^99m^Tc‐SnF~2~ colloid. This indicates that the level of opsonization of radiocolloid is rate limiting rather than the phagocytic capacity of liver and spleen macrophages. There is a low level of ^99m^Tc‐SnF~2~‐labelled‐leucocytes dominated by unopsonized radiocolloid in the ex vivo whole blood dose. Following administration of this dose, free radiocolloid is present in vivo that predominantly localizes in the liver and spleen. This uptake can be challenged with non‐radioactive stannous fluoride colloid pre‐injection, where splenic activity can be significantly reduced by up to 52%. Copyright © 2003 John Wiley & Sons, Ltd.