Improved Calibration of Tm-Chleates for Use in MR Thermometry

Michael A. Boss¹

The temperature-dependence of the chemical shift agents Tm-DOTA and Tm-DOTMA was determined from 5-45 &[deg]C in vitro. Previous measurements of the chemical shift of proton residues on lanthanide-chelates had indicated a linear dependence on temperature over small temperature ranges. However, it was found that linear calibrations can lead to errors of several degrees when using the -CH&[deg] ₃ of Tm-DOTMA chemical shift as an MR thermometer. Our measurements over a larger temperature range indicate a non-linear dependence, and greatly improve the accuracy of MR thermometry performed with Tm-chelates.