Free ligand and free Gd³⁺ ions are both highly toxic to living systems. Free Gd³⁺ ions may have a profound effect on the contrast in the MR image. Therefore any Gd complex preparation has to be carefully checked for the content of free ligand and free metal ions. Herein the currently used procedures that allow to assess the amounts of free metal ions and free ligand in a solution of a given Gd complex are described in detail.

The intraarterial injection of diluted Super Paramagnetic Particles of Iron Oxide (SPIO)of 10 mmol Fe/l in an animal model temporary changes the intraluminal field strength during Magnetic Resonance Angiography (MRA) and results in dark blood images, which is potentially useful during interventional imaging.

Many disease-specific, small molecule targeting ligands exhibit high charge and/or hydrophobicity. We describe a general-purpose HPL/mass spectrometry platform for the development of multimodality contrast agents and targeted therapeutics derived from such ligands. Using highly anionic small molecules specific for prostate-specific membrane antigen as examples, we demonstrate that agents prepared using this platform target living human prostate cancer cells with high affinity and specificity.

Cellular uptake of FET was studied on rat osteosarcoma cells (ROS 17/2.8) and human leukocytes, initially loaded with non radioactive L-tyrosine, in order to measure potential effects of AA content on the distinction between tumor and inflammatory lesions. ROS 17/2.8 showed a higher sensitivity to preload effects on FET uptake than the leukocytes, which suggests that preload with L-tyrosine, prior to the administration of FET, may be a potential procedure to improve PET differentiation between tumor and inflammation.