Feasibility of the microwave and ultrasound ablation as alternatives to treat bone tumors

This study was made in order to prove the feasibility of two of the most promising thermal therapies to treat bone tumors. Microwave (MW) and ultrasound (US) ablation were analyzed. For MW ablation, a single slot antenna was designed. The best characteristics of the antenna, to generate an electromagnetic field and its absorption by the bone, were obtained by a parametric modeling. Length and location of the slot and work frequency were analysed. On the other hand, for US ablation, the acoustic propagation of a 4 MHz spherical transducer was done. Then, two models were proposed: in water and in a 2 layer media (water and bone). Four antennas with the best characteristics to heat up bone were chosen (best cases scenarios). The optimal length position was 6.9 mm (slot length 1 mm & 2 mm) and 4.9 (slot length: 3 mm & 4 mm). These antennas work properly from 2.45 GHz– 2.60 GHz. The SWR was around 1.22±0.07 (m±sd). Finally, these antennas show a covered area of 10.23±0.05 cm
²
(m±sd) of bone tissue. Acoustic and thermal distributions depict that US can enter 5 mm in the bone. This results show that both techniques are suitable to treat bone tumors.