Comparative analysis of hepatopulmonary shunt obtained from pretherapy 99mTc MAA scintigraphy and post-therapy 90Y Bremsstrahlung imaging in 90Y microsphere therapy

Introduction Tc-99m macroaggregate albumin (MAA) scintigraphy is routinely used to estimate the hepatopulmonary shunt (HPS) of Y-90 microspheres because of their comparable average particle sizes (20-30 mu m). However, the MAA particle size can vary from 10 to 90 mu m. Therefore, HPS computed from Tc-99m MAA scintigraphy may not accurately represent the HPS of Y-90 microspheres. In view of this, the present study was undertaken to investigate the accuracy of Tc-99m MAA scintigraphy in estimating the HPS of Y-90 microspheres. Materials and methods Nineteen sessions of transarterial radioembolization using Y-90 therasphere were carried out in 17 patients for hepatic malignancies (both primary and secondary). For each session of therapy, a pretherapeutic Tc-99m MAA scintigraphy and post-therapeutic Y-90 Bremsstrahlung scintigraphy were performed. The HPSs obtained from these images were compared. Results The mean HPS fractions calculated from the pretherapeutic Tc-99m MAA study and the post-therapeutic Y-90 Bremsstrahlung images were 4.77 +/- 2.81 and 4.52 +/- 2.5%, respectively. The coefficient of correlation (r) was 0.96. Conclusion Tc-99m MAA scintigraphy accurately predicts the H PS of Y-90 microspheres. Nucl Med Commun 33:486-490 (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.