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.
Original language | English (US) |
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Pages (from-to) | 1609-1621 |
Number of pages | 13 |
Journal | Ultrasound in Medicine and Biology |
Volume | 37 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2011 |
Externally published | Yes |
Keywords
- Arrays
- Image guidance
- Liver cancer
- Therapeutic ultrasound
- Thermal ablation
- VX2 rabbit tumor
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Biophysics
- Acoustics and Ultrasonics