Syringe Filter Method for Quality Control of Technetium-99m-MAA

Abstract

Objective: A syringe filter method (SFM) was compared with instant thin-layer chromatography (ITLC) for radiochemical purity analysis of ^99mTc-MAA.

Methods: MAA kits from two manufacturers were radiolabeled. Technetium-99m-MAA preparation (0.2 ml) was drawn through a 5-micron or 0.45-micron pore-size filter into an attached 3-ml syringe, followed by a saline and air rinse where possible. Percent radiochemical impurities (% RCI) was determined by comparison of filtrate and total syringe activity. Radiochemical analysis of filtrate was performed by ITLC. Low-particle number ^99mTc-MAA (^99mTc-MAA-LPN) was also tested by the SFM and ITLC at time points up to 60 min post-preparation.

Results: Percent RCI by the SFM was sometimes significantly different from, but never lower than, ITLC. The 5-micron filter detected significantly higher % RCI than the 0.45-micron filter in certain cases. Filtrate analysis revealed the ability of the SFM to quantify radiocontaminants. Tests on ^99mTc-MAA-LPN preparations revealed high correlation (r > 0.93) between % RCP determined by the SFM and ITLC.

Conclusion: The SFM was fast and accurate for quality control analysis of ^99mTc-MAA preparations. The 5-micron syringe filter is preferred because of its accuracy and ease of use.