FDTD simulations to assess the performance of CFMA-434 applicators for superficial hyperthermia.

Introduction: Contact flexible microstrip applicators (CFMA), operating at 434 MHz, are applied at the Academic Medical Center (AMC) for superficial hyperthermia (e.g. chest wall recurrences and melanoma). This paper investigates the performance of CFMA, evaluating the stability of the specific absorption rate (SAR) distribution, effective heating depth (EHD) and effective field size (EFS) under different conditions.Methods: Simulations were performed using finite differences and were compared to existing measurement data, performed using a rectangular phantom with a superficial fat-equivalent layer of 1 cm and filled with saline solution. The electrode plates of the applicators measure ∼7 × 20, 29 × 21 and 20 × 29 cm2. Bolus thickness varied between 1 and 2 cm. The impact of the presence of possible air layers between the rubber frame and the electrodes on the SAR distribution was investigated.Results: The EHD was ∼1.4 cm and the EFS ranged between ∼60 and ∼300 cm2, depending on the applicator type. Both...