IntroductionCancer treatments remain a heavy load for the patient due to the many side effects. Mild hyperthermia, locally heating tissue to 42⁰ C, has proven to be a powerful treatment enhancer with no severe side effects. Recently, new potential applications of mild hyperthermia in cancer therapy were discovered. Converting these cell-culture based findings into clinical protocols requires pre-clinical investigation of the various strategies by clinical trials with small animals. For this goal, a site-specific head & neck hyperthermia applicator for murine models was developed. Hereto, we studied a design with an antenna array operating at 2.45 GHz embedded in a water bolus.Methodology A simulation-based approach was used to design the separate antennas operating at 2.45 GHz, and later on the antenna array. Simulation programs SEMCAD and CST are used, both of which use a Finite Difference Time Difference (FDTD) calculation methods. The design yields an air-water boundary between the antenna feed and antenna arms. To reduce detuning due to varying water levels, the connections between those elements (feed lines) were embedded within the PCB. A capacitive patch, also used for attachment of the connector, matched the antenna to 50 Ohm. Next, the antenna return loss (S11) was experimentally validated for various circumstances. Lastly, the single antenna and array performance was assessed by simulating first the power absorption distributions, and second the temperature distribution using Penne’s bioheat equation . ResultsThe Simulation results as well as measurements show that the antenna is stable for variations in water levels. Simulation results of a grid of nine antennas show that controlled and focused application of heat can be delivered at target regions under the tongue, and that 14-25W suffices.ConclusionsBased on these promising results, we will now embark on experimental validation of the heating performance of a single antenna setup: firstly in tissue-equivalent gels and secondly in vivo.
|Publication status||Published - 7 Dec 2015|
|Event||Joint URSI - NARF - AP-S Symposium - Drienerburcht, Twente, Netherlands|
Duration: 7 Dec 2015 → 7 Dec 2015
|Conference||Joint URSI - NARF - AP-S Symposium|
|Period||7/12/15 → 7/12/15|