Advances in the Planning and Control of the MR-guided Regional Hyperthermia Applications

A novel method for improved planning and control of the magnetic resonance (MR)-guided hyperthermia (HT) has been developed and tested in the combined Berlin MR-HT hybrid system, consisting of the 12-channel HT applicator Sigma-Eye and of the MR tomograph Siemens MAGNETOM Symphony 1.5 T. The method is based on a step-by-step adaptation of antenna profiles (single antenna fields) using MR temperature rise measurements obtained by the proton resonance frequency shift (PRFS) method. A Gauss-Newton algorithm is applied as an iterative solver for adaptation. It is shown that, using the finite-difference time-domain (FDTD) method as initial estimate for antenna profiles, already after few adaptation steps a significant improvement of the specific absorption rate (SAR) predictability in the MR-HT hybrid system is reached.