A novel ultrasonography-guided high intensity focused ultrasound (HIFU) system (FS-100;
Force Electronics Co. Ltd, Chongqing, China) was developed for non-invasive thermal
ablation of tumor. The proprietary therapy delivery system is an integration of the
digital image progressing, automatic control and the high intensity focused ultrasound
thermal ablation devices. The therapeutic ultrasound probe (phi = 240 mm) consists
of eight circular HIFU transducers with a curved surface of a diameter of 60 mm. Dual
focused beams generated from the probe were used in this system for thermal delivery.
The probe has the maximal resonance frequency of 1 MHz, a maximal treatment depth
of 160 mm and focal spot diameter of 3 mm. The maximal intensity at the focal spot
is 10,000 W/cm(2). The imaging and HIFU components are located on top of the device,
therefore, the focused ultrasound beams can be delivered to the patient in a supine
position. The motion, targeting and localization of the probe are controlled by a
PMAC-PC motion controller and an 8-independent-axis mechanical device. The linear
motion error of the probe localization is less than or equal to 0.1 mm. The ultrasonographic
image information is used for treatment planning and therapeutic interventions, such
as target definition and registration, visualization of the three-dimensional anatomy
of desired target(s), automatic positioning the thermal beams on targets, controlling
thermal delivery, and rapid evaluation of target response post-treatment. The preclinical
experimental results will be presented. The safety, feasibility and effectiveness
of this novel HIFU system will be tested.
