Influence of MR thermometry on predicted temperature during regional hyperthermia treatment

Hyperthermia treatment involves heating tissues to 40–44 °C in order to enhance the efficacy of radiotherapy and/or chemotherapy. Temperature increase is usually induced by the constructive interference of several electromagnetic waves radiating from external sources and can be monitored using magnetic resonance (MR) thermometry. This study aimed to predict temperature increases from non-invasive MR thermometry electromagnetic exposure during deep regional hyperthermia treatment. A 1.5T MR birdcage coil was tuned to produce a homogeneous B1+ field and simulated together with the Sigma Eye hyperthermia applicator and three available patient models. Results show that electromagnetic exposure during MR measurements increases temperature by 0.027 °C, which is, in the hyperthermia temperature range, insignificant. In addition, our results show that the predicted B1+ field homogeneity was influenced by object size and material properties, especially by the water bolus filling the inner part of the applicator.