Modified Preparation and Rapid Quality Control Test for Technetium-99m-Tetrofosmin

Abstract

Objective: The objectives of this study were to: modify the preparation of ^99mTc-tetrofosmin by using twice the amount of ^99mTcO₄⁻ recommended by the manufacturer; evaluate the use of miniaturized rapid paper chromatography (MRPC) for quality control (QC) testing; and determine the in vitro stability of the modified preparation using MRPC.

Methods: Two preparations of ^99mTc-tetrofosmin were made: one with 4.4–8.8 GBq (120–240 mCi) and the other with 13.9–17.6 GBq (380–480 mCi) ^99mTcO₄⁻, referred to as regular and modified preparations, respectively. Routine QC tests were performed using MRPC and instant thin-layer chromatography/silica-gel (ITLC/SG) systems. The preparations were injected into 58 patients. Planar and SPECT images of stress and rest studies were obtained. The technical quality of the SPECT images was graded visually by four observers. Heart-to-lung and heart-to-background ratios were calculated from the planar images.

Results: The QC testing procedure took 4.18 ± 0.15 min with MRPC and 54 ± 5.3 min with ITLC/SG systems. The percent labeling efficiency, as determined by both techniques, ranged from 95.6 ± 1.6 to 97.2% ± 0.8%. Both preparations were stable up to 6 hr after reconstitution. There was no difference between the cardiac-to-lung and cardiac-to-background ratios of the two preparations.

Conclusion: The results indicate that MRPC is a faster and effective chromatographic technique for routine QC testing of ^99mTc-tetrofosmin. Doubling the amount of ^99mTcO₄⁻ used in preparing ^99mTc-tetrofosmin did not affect its in vitro stability, its efficacious use in patients or the technical quality of the images.