Relaxation times in paramagnetically doped agarose gels as a function of temperature and ion concentration

Tissue equivalent gels of NMR phantoms have been investigated at 3.4 MHz. The proton T1 and T2 relaxation times have been measured in Ni++ and Cu++ doped agarose gels as a function of temperature and ion concentration. Ni-agarose gels have the lower T1 temperature dependence, but gels containing both Cu++ and Ni++ can be produced for which T1 has virtually no temperature dependence.