In the near future there would be a need for a high field MRI contrast agent for the MRI diagnostic due to the several disadvantages of Gd-based complexes, such as short circulation time and decrease in efficiency at high magnetic field i.e., greater than 3 T. The lanthanide-based nanoparticle can be an alternative to these complexes due to a high density of metal ions per unit of contrast agent. The high density of the metal ions will enable the MR signal shortening usually, at lower concentrations compared to chelates that typically are used at micro-molar concentrations. Additionally, the nanoparticles would retain their relaxivity efficiency at high magnetic field greater than 3 T
