Design and implementation of intravascular hifu catheter ablation system

Official URL: http://risc01.sabanciuniv.edu/record=b1817066 (Table of Contents)

High-intensity focused ultrasound is an energy-based thermal therapy for noninvasive or minimally invasive treatment of wide range of medical disorders including solid cancer tumors, brain surgery, atrial fibrillation (AF) and other cardiac arrhythmias. Conventional HIFU is extracorporeally administered but in applications where a small lesion or more precise energy localization in shorter time is required, catheter-based HIFU devices which are positioned directly within or adjacent to the target may be the best solution. Available HIFU catheters use array of piezoelectric transducers with complex external high-voltage (HV) and high-frequency amplifiers, a cooling system and several coaxial cables within the catheter. In this study, a HV transmitter IC has been designed, manufactured and integrated with an 8-element capacitive micromachined ultrasound transducer (CMUT) on a prototype HIFU probe appropriate for a 6-Fr catheter. The transmitter IC fabricated in 0.35 μm HV CMOS process and comprises eight continuouswave HV buffers (10.9 ns and 9.4 ns rise and fall times at 20 Vpp output into a 15 pF), an eight-channel transmit beamformer (8-12 MHz output frequency with 11.25 º phase accuracy) and a phase locked loop with an integrated VCO as a tunable clock source (128–192 MHz). The chip occupies 1.85×1.8 mm2 area including input and output (I/O) pads. Electrical measurements, IR thermography and Ex-vivo experiment results reveal that the presented HIFU system can elevate the temperature of the target region of tissue around 19 ºC by delivering 600 CEM43 equivalent thermal dose while surface temperature of the probe rises less than 5 ºC