High-intensity focused ultrasound has been used experimentally to ablate hepatic, brain, and subcutaneous tumors without damaging adjacent tissues. We report our pilot experience in dogs using this modality to ablate prostatic tissue. Six dogs subjected to acute injury were sacrificed one hour after focused ultrasound ablation; four dogs subjected to chronic injury were sacrificed two, four, six, and twelve weeks post ablation. The pathology of the acute injury and chronic response to this injury is presented. High-volume ablation was created without injury to adjacent tissue. Grossly, the post-ablation prostate appears identical to the posdt-TUR-P defect. Subsequently, a combined imaging/therapy transrectal transducer has been developed and has been used in six dogs. The size and appearance of this probe is similar to current commercially available transrectal imaging probes. Prostate ablation was successful in all dogs and no injury to the rectal wall was apparent when energy levels were appropriate. Again, the post ablation prostate resembled a TUR-P defect. The implications of these findings using this new modality are potentially immense. Plans for human trials are being formulated.
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