In Situ Treatment of Liver Using Catheter Based Therapeutic Ultrasound with Combined Imaging and Gps Tracking

Extensive surgical procedure or liver transplant still remains the gold standard for treating slow-growing tumors in liver. But only few candidates are suitable for such procedure due to poor liver function, tumors in unresectable locations or presence of other liver diseases. In such situations, minimally invasive surgery may be the best therapeutic procedure. The use of RF, laser and ultrasound ablation techniques has gained considerable interest over the past several years to treat liver diseases. The success of such minimally invasive procedure depends on accurately targeting the desired region and guiding the entire procedure. The purpose of this study is to use ultrasound imaging and GPS tracking system to accurately place a steerable acoustic ablator and multiple temperature sensors in porcine liver in situ. Temperature sensors were place at eight different locations to estimate thermal distribution in the three-dimensional treated volume. Acoustic ablator of center frequency of 7 MHz was used for the experiments. During therapy a maximum temperature of 60-65 °C was observed at a distance 8-10 mm from the center of the ablation transducer. The dose distribution was analyzed and compared with the gross pathology of the treated region. Accurate placement of the acoustic applicator and temperature sensors were achieved using the combined image-guidance and the tracking system. By combining ultrasound imaging and GPS tracking system accurate placement of catheter based acoustic ablation applicator can be achieved in livers in situ.