Experimental and computational evaluation of capacitive hyperthermia.

Area of Science:

• Oncology
• Medical Physics
• Biomedical Engineering

Background:

• Hyperthermia enhances radio- and/or chemotherapy efficacy, as confirmed by clinical trials.
• Capacitive hyperthermia systems (CHS) show promise, but their deep-region specific absorption rates (SAR) are less understood compared to other techniques.
• A lack of systematic SAR measurements for current capacitive technology necessitates further investigation.

Purpose of the Study:

• To systematically measure specific absorption rates (SAR) for capacitive hyperthermia systems (CHS).
• To evaluate the heating capabilities of CHS in phantom models simulating various tissue compositions and depths.
• To combine phantom measurements with simulation studies for a comprehensive understanding of CHS performance.

Main Methods:

• Manufactured homogeneous and inhomogeneous agarose phantoms according to guidelines.
• Utilized the commercial CHS Celsius42, registering temperature/time curves.
• Derived SAR profiles and distributions using the temperature gradient method and Sim4Life simulations.

Main Results:

• Effective SAR up to 6-8 cm depths was measured in homogeneous phantoms at 200W, indicating suitability for superficial and intermediate tumors.
• A 1 cm fat layer reduced SAR but still achieved 10-20 W/kg in intermediate to deep regions (2-10 cm).
• Low SAR (5-10 W/kg) was measured in bone phantoms; simulations generally agreed with measurements but tended to predict higher SAR.

Conclusions:

• Capacitive hyperthermia systems are suitable for heating superficial and medium-deep tumors, including some bone metastases.
• CHS application is feasible for specific patient groups with pelvic and abdominal tumors.
• Findings align with positive clinical studies on CHS efficacy.