High-Intensity Focused Ultrasound Ablation of Rabbit Kidney Tumors

Abstract

High-intensity focused ultrasound (HIFU) is a noninvasive surgical technique in which ultrasound energy is delivered transcutaneously to a discrete area within the body. This energy can result in a well-defined zone of cellular death within the targeted tissue. We used HIFU in an effort to ablate rabbit VX-2 kidney tumors. A tumor cell suspension was injected into a renal segmental artery (Phase 1, nine rabbits) or directly into the lower pole parenchyma (Phase 2, nine rabbits). After a 2-week incubation period, open direct contact (Phase 1) or transcutaneous ablation (Phase 2) was performed. In Phase 1, after sonablation, there was pathologic evidence of tissue destruction in nine animals, and seven had both gross and histologic evidence of tumor ablation. There was sharp demarcation between viable and ablated tissue. In Phase 2, pathologic evidence of kidney ablation was seen in seven of nine animals. However, only two rabbits showed the well-demarcated effects of ablation in the tumor. High-intensity focused ultrasound can be effective at causing cell death in renal tumors and surrounding renal tissue. However, with the present ultrasound technology, imaging of renal lesions in the rabbit model is not adequate to consistently localize and completely ablate tumor.