title: Treatment of rabbit liver cancer in vivo using miniaturized image-ablate ultrasound arrays.
abstract: In the preclinical studies reported here, VX2 cancer within rabbit liver has been treated by bulk ultrasound ablation employing miniaturized image-ablate arrays. Array probes were constructed with 32 elements in a 2.3 × 20 mm(2) aperture, packaged within a 3.1 mm stainless steel tube with a cooling and coupling balloon for in vivo use. The probes were measured capable of 50% fractional bandwidth for pulse-echo imaging (center frequency 4.4 MHz) with >110 W/cm(2) surface intensity available at sonication frequencies 3.5 and 4.8 MHz. B-scan imaging performance of the arrays was measured to be comparable to larger diagnostic linear arrays, although nearfield image quality was reduced by ringdown artifacts. A series of in vivo ablation procedures was performed using an unfocused 32-element aperture firing at 4.8 MHz with exposure durations 20-70.5 s and in situ spatial average, temporal average intensities 22.4-38.5 W/cm(2). Ablation of a complete tumor cross-section was confirmed by vital staining in seven of 12 exposures, with four exposures ablating an additional margin >1 mm beyond the tumor in all directions. Analysis suggests a threshold ablation effect, with complete ablation of tumor cross-sections for exposures with delivery of >838 J acoustic energy. The results show feasibility for in vivo liver cancer ablation using miniaturized image-ablate arrays suitable for interstitial deployment.
authors.affiliation: Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH 45267-0586, USA. doug.mast@uc.edu
authors.forename: T Douglas
authors.initials: TD
authors.lastname: Mast
authors.forename: Peter G
authors.initials: PG
authors.lastname: Barthe
authors.forename: Inder Raj S
authors.initials: IR
authors.lastname: Makin
authors.forename: Michael H
authors.initials: MH
authors.lastname: Slayton
authors.forename: Chandra Priya
authors.initials: CP
authors.lastname: Karunakaran
authors.forename: Mark T
authors.initials: MT
authors.lastname: Burgess
authors.forename: Amel
authors.initials: A
authors.lastname: Alqadah
authors.forename: Steven M
authors.initials: SM
authors.lastname: Rudich
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods; D004195:Disease Models, Animal; D004867:Equipment Design; D005240:Feasibility Studies; D008114:Liver Neoplasms, Experimental / Q000000981:diagnostic imaging / Q000628:therapy*; D008904:Miniaturization; D009368:Neoplasm Transplantation; D011817:Rabbits; D059708:Ultrasonic Surgical Procedures / Q000295:instrumentation* / Q000379:methods; D014463:Ultrasonography