Impact of preconditioning pulse on lesion formation during high-intensity focused ultrasound histotripsy
| Autor: | Timothy A. Bigelow, Jin Xu, Grant Riesberg |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Materials science
Acoustics and Ultrasonics Swine medicine.medical_treatment Biophysics In Vitro Techniques Radiation Dosage Lesion Histotripsy Optics medicine Animals Radiology Nuclear Medicine and imaging Muscle Skeletal Radiological and Ultrasound Technology Pulse (signal processing) business.industry Ablation High-intensity focused ultrasound Intensity (physics) Amplitude Cavitation High-Intensity Focused Ultrasound Ablation medicine.symptom business Biomedical engineering |
| Zdroj: | Ultrasound in medicinebiology. 38(11) |
| ISSN: | 1879-291X |
| Popis: | Therapeutic applications with high-intensity focused ultrasound (HIFU) fall into two classifications-one using thermal effect for coagulation or ablation while generally avoiding cavitation and the other using cavitation-mediated mechanical effects while suppressing heating. Representative of the latter, histotripsy uses HIFU at low duty factor to create energetic bubble clouds inside tissue to liquefy a region and has the advantages in real-time monitoring and lesion fidelity to treatment planning. We explored the impact of a preconditioning/heating pulse on histotripsy lesion formation in porcine muscle samples. During sonication, a targeted square region 9 mm wide (lateral to the focal plane) was scanned in a raster pattern with a step size of 0.75 mm. The 20-s exposure at each treatment location consisted of a 5-s duration preconditioning burst at spatial-peak intensities from 0-1386 W/cm² followed by 5000 tone bursts at high intensity (with spatial-peak pulse-average intensity of 47.34 kW/cm², spatial-peak temporal-average intensity of 284 W/cm², peak compressional pressure of 102 MPa and peak rarefactional pressure of 17 MPa). The temperature increase for all exposures was measured using a thermal imager immediately after each exposure. Lesion volume increased with increasing amplitude of the preconditioning pulse until coagulation was observed, but lesion width/area did not change significantly with the amplitude. In addition, the lesion dimensions became smaller when the global tissue temperature was raised before applying the histotripsy pulsing sequence. Therefore, the benefit of the preconditioning pulse was not caused by global heating. |
| Databáze: | OpenAIRE |
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