High-Intensity Focused Ultrasound for ex Vivo Kidney Tissue Ablation: Influence of Generator Power and Pulse Duration
| Autor: | Ernst Marlinghaus, Kai Uwe Köhrmann, Annette Steidler, Thomas Knoll, Axel Häcker, Sigrun Langbein, Oliver Kraut, Maurice Stephan Michel, Peter Alken |
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| Rok vydání: | 2004 |
| Předmět: |
Hydrophone
Swine Parabolic reflector business.industry Ultrasonic Therapy Urology medicine.medical_treatment Ultrasound Pulse duration Anatomy In Vitro Techniques Kidney Ablation High-intensity focused ultrasound Coagulative necrosis medicine Animals Ultrasonics business Sound pressure Biomedical engineering |
| Zdroj: | Journal of Endourology. 18:917-924 |
| ISSN: | 1557-900X 0892-7790 |
| Popis: | The therapeutic application of noninvasive tissue ablation by high-intensity focused ultrasound (HIFU) requires precise physical definition of the focal size and determination of control parameters. The objective of this study was to measure the extent of ex-vivo porcine kidney tissue ablation at variable generator parameters and to identify parameters to control lesion size.The ultrasound waves generated by a cylindrical piezoceramic element (1.04 MHz) were focused at a depth of 100 mm using a parabolic reflector (diameter 100 mm). A needle hydrophone was used to measure the field distribution of the sound pressure. The morphology and extent of tissue necrosis were examined at generator powers of up to 400 W (P(el)) and single pulse durations of as long as 8 seconds.The two-dimensional field distribution resulted in an approximately ellipsoidal focus of 32 x 4 mm (-6 dB). A sharp demarcation between coagulation necrosis and intact tissue was observed. Lesion size was controlled by both the variation of generator power and the pulse duration. At a constant pulse duration of 2 seconds, a generator power of 100 W remained below the threshold doses for inducing a reproducible lesion. An increase in power to as high as 400 W induced lesions with average dimensions of as much as 11.2 x 3 mm. At constant total energy (generator power x pulse duration), lesion size increased at higher generator power.This ultrasound generator can induce defined and reproducible necrosis in ex-vivo kidney tissue. Lesion size can be controlled by adjusting the generator power and pulse duration. Generator power, in particular, turned out to be a suitable control parameter for obtaining a lesion of a defined size. |
| Databáze: | OpenAIRE |
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