Microwave hyperthermia (HT) is a clinically validated adjunct to radio- and chemotherapy: by raising tumor temperature using non-ionizing electromagnetic fields, it increases radiosensitivity and improves intratumoral drug delivery without adding significant toxicity. Achieving effective yet safe heating requires accurate control of the spatial temperature distribution. Inadequate heating of tumor tissue reduces treatment efficacy, whereas excessive heating of healthy tissues may cause irreversible damage. Reliable temperature monitoring is therefore critical for both safety and effectiveness in hyperthermia treatments. In current clinical practice, especially for deeper targets, temperature monitoring mainly relies on catheter-based invasive thermometry, which samples only a few measurement points. Since catheter placement causes discomfort and procedural burden, their number must be minimized preventing a comprehensive characterization of the temperature distribution within the region of interest (ROI).