Molecular Imaging

Note the high uptake of Ga-68-pentixafor on multi-planar reconstructions in the organs expressing CXCR4 such as the spleen (red arrows) and adrenal glands (yellow arrows), which was nearly completely blocked by the pre-injection of AMD 3100, a potent CXCR4 inhibitor. Strong accumulation of Ga-68-pentixafor was also found in the kidneys (asterisks) reflecting the renal clearance of the tracer. In addition, high, focal activities were detected in the abdominal aorta (red arrowheads) and right carotid artery (orange arrowheads) of atherosclerotic rabbits, whereas no significant signal could be detected in the non-injured left carotid artery (white arrowheads) of atherosclerotic and control rabbits, as well as in the abdominal aorta and right carotid artery of control rabbits. Furthermore, focal activities detected with PET in atherosclerotic plaques of the abdominal aorta and the right carotid artery decreased significantly when the same rabbit was re-imaged after blocking CXCR4 receptors. Image courtesy of Fabien Hyafil, M.D., Ph.D., Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany

Comparative receptor autoradiography in various cancer types (A = HE staining) with I-125-JR11 (B+C) and I-125-Tyr3-octreotide (D+E). B and D are the respective total binding, C and E the respective non-specific binding. Bars = 1 mm.

I: Breast cancer. II: Renal cell cancer. III: Medullary thyroid cancer. IV: Non-Hodgkin lymphoma. V: Colon cancer. In cancers I-V, the sections were incubated with 30’000 cpm/100 μl of antagonist or agonist. Cancers I-IV show a much higher density of sst2 with the antagonist. The colon cancer V is negative. VI: Ileal NET, incubated with 10’000 cpm/100 μl of antagonist or agonist. Credit: Jean Claude Reubi, Institute of Pathology, University of Berne, Berne, Switzerland.