BMM tissue distribution assessed by SPECT and histologic tests. (A) BMM migration and tissue distribution of ¹¹¹In-labeled BMMs are illustrated by SPECT analysis. Planar presentations of the tomographic images from a representative mouse show that radiolabeled BMMs initially accumulate in the lung (Lun), liver (Liv), and spleen (Spl). (B) To quantify BMM migration, ROIs were circumscribed and radioactive counts determined as a function of time (in days) after adoptive transfer. Data represent mean ± SEM for 4 mice. (C) Histologic analysis of Feridex-labeled BMMs, as determined by Prussian blue staining (blue cells), was consistent with SPECT data. BMMs in liver and lung were less than observed in spleen after day 7. Magnifications are (originals) × 100 and (insets) × 400.