Samenvatting

Cancer is a worldwidehuman health problem.This is why much effortis put in finding solutions and treatments for this disease. One of the emerging adjuvant cancer treatments, hyperthermia, is applied by heating the tumourtissue, and is shown to increase the effects of radio and/ or chemotherapy.

Because of the difficulty in the controlled heating inside thehead and neck region, the MRlabcollarapplicator has been designed. This applicator uses twelve antennaeto heat specific parts of tissue, and can be used inside the MRI, since the use of Ferro-magneticmaterials was minimised. This way, the temperature distribution can be visualised during the measurement.

In order to simulate the measurements of the MRlabcollar, some parametersneed to be verified. first, anexperimental phantom was fabricated,whichthe human neck for its dielectricproperties. The antenna impedance, as well as its sensitivity tochanges inthe phantom, temperature and input power weremeasured. Also, the coupling between the antennaewas measured.

The antenna's impedance showed no significant reactiondue to the changes inthe phantommaterial. The temperature however affected the resonance frequency, and thus the impedance of the antenna.In order for the antennaeto resonate at 434 MHz, which is a frequency reserved for scientific experiments, the optimal temperature is somewhere between 30 and 35 °C.

This was further shown during the power measurements. When power was increased, the temperature, and thus the return loss of the antennae increased.

The total coupling of the antennaeat 434 MHzwas found to be between -8 and -9dB. The coupling between individualantennaeis measured on-16dB.

During the measurements we found that antenna 1_2 shows variancein its return loss when its cable is moved, an effect not seen by the other