Laparoscopic partial kidney ablation using high‐intensity focused ultrasound

A laparoscopic ultrasound probe was developed for image‐guided high‐intensity focused ultrasound (HIFU) ablation of renal tissue. The probe expands the application of a commercially available HIFU system (Sonablate^TM) to laparascopic operations. It consists of a 4‐MHz focused rectangular HIFU piezoceramic transducer (30×10 mm, FL=30 mm) confocally coupled with a circular central element (8 mm in diameter) used for real‐time pulse‐echo imaging during treatment. Precise mechanical movements of the transducer enable it to treat targeted tissue volumes. The probe was fully characterized by measuring its electrical impedance, acoustic field, and total acoustic power output. Moreover, the acoustic field was simulated using an analytical model. The laparoscopic probe was able to generate acoustic power levels up to 35 W that correspond to focal intensities over 2200 W/cm² in tissue, sufficient for tissue ablation through rapid temperature rise (>90<th>°C) and cavitation mechanisms. The probe was tested in an in vivo animal study in which 15 pigs were treated through a sterile laparoscopic procedure. A lesion with dimensions of 23×17×11 mm ±1 mm was successfully generated in the left kidney of each pig during a treatment time of less than 30 min. Histology results demonstrated homogeneous well‐delineated lesions generated in the target region.