Heating Properties of Needle Applicator Made of Shape Memory Alloy for Brain Tumor Hyperthermia

This paper describes a new heating method used to expand the heating area of a needle applicator by using a needle applicator made of a shape memory alloy (SMA) for brain tumor hyperthermia treatment. The purpose of the study described here is to show the ability of the method to expand a defined heating region. One major disadvantage of RF interstitial hyperthermia treatment is that this heating method has a small heating area. To overcome this problem, a new type of needle made of a SMA was developed. The thermal properties of this proposed method, when applied to agar phantoms, were calculated with computer simulations and these properties were checked experimentally with the current physical version of the heating system. The calculated temperatures were in close agreement with the measured temperatures with an error of 10% or less. In both the numerical calculations and experimental results the proposed SMA needle heat treatment expanded the heating area to approximately 300% of that of a non-SMA needle heat treatment. These results suggest that the proposed heating method using the SMA needle applicator is capable of being used for invasive brain tumor hyperthermia treatments.