title: Effect of echo-guided high-intensity focused ultrasound ablation on localized experimental tumors.
abstract: We fabricated a prototype 3.25-MHz split-focus therapeutic transducer combined with a small 6.5-MHz imaging ultrasonic probe for transrectal treatment of prostate cancer and evaluated the feasibility of using split-focus high-intensity focused ultrasound (HIFU) to ablate localized tumor tissue without injuring the surrounding organs. We therefore established a localized tumor model by inoculating VX2 tumor into rabbit livers. The localized VX2 tumors of nine rabbits were transdermally treated with split-focus ablation at a peak intensity in water of 6 kW/cm2 for 4 s (6 shots) under the guidance of ultrasonic B-mode imaging. Necropsy a day after treatment found the surface of the livers and gastrointestinal tracts to be grossly normal. The VX2 tumors were completely coagulated and were surrounded by ablated liver tissue. The six shots of split-focus HIFU destroyed the VX2 tumors without injuring the liver surfaces or the surrounding organs. These results suggest that split-focus HIFU ablation could be an effective treatment of localized tumors.
authors.affiliation: Central Research Laboratory, Hitachi, Ltd., Tokyo, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Sasaki
authors.forename: Mohamed S
authors.initials: MS
authors.lastname: Medan
authors.forename: Takashi
authors.initials: T
authors.lastname: Azuma
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Kawabata
authors.forename: Minoru
authors.initials: M
authors.lastname: Shimoda
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Umemura
mesh_terms: D000818:Animals; D005260:Female; D008114:Liver Neoplasms, Experimental / Q000000981:diagnostic imaging* / Q000601:surgery*; D011817:Rabbits; D018084:Ultrasonography, Interventional / Q000379:methods / Q000662:veterinary