Loco-regional Hyperthermia Delivery: Patient-specific set-up Procedures for Treatment Optimisation

Locoregional hyperthermia (heating of deep-seated tumours to 40-43°C) increases effectivity of chemotherapy and radiotherapy. Phased arrays of antennas are positioned around the patient, using phase steering to focus energy deposition onto the tumour. This paper describes patient-specific set-up procedures for treatment optimisation for locoregional hyperthermia devices using an E-Field probe at or near the tumour location. A phase-sweep is performed for each individual antenna w.r.t. a reference antenna to determine the optimal phase-setting, yielding a maximum EField signal. A phase-shift is applied when the probe cannot be positioned at the tumour location. Correctness of phase settings thus found is verified using temperature rise measurements after a 60 sec power pulse for three different phase settings. Effectivity of the method is demonstrated by numerical simulations and clinically for patients with a cervical and bladder tumour. Results show this is a robust patient-specific method for clinical phase optimisation during locoregional hyperthermia.