Topic overview

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Lanthanides’ unpaired 4f electrons contribute to strong paramagnetism and distinctive luminescence. In MRI, chelated Gd³⁺ can enhance T₁-weighted signal by affecting the relaxation of nearby water protons; stable ligands are important because free gadolinium is cytotoxic. Contrast-agent classes, relaxivity-enhancement factors, and alternative paramagnetic ions are part of the topic. For optical diagnostics, Eu³⁺ and Tb³⁺ can produce long-lived emissions that support time-gated imaging and assay formats, while other lanthanides and upconversion nanoparticles offer additional optical approaches. The lesson also introduces targeted and dual-modal probes, linking MRI contrast and luminescence to potential diagnostic applications.