| MR-guided adaptive focusing of therapeutic ultrasound beams in the human head. | |
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MedLine Citation:
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PMID: 22320825 Owner: NLM Status: In-Data-Review |
Abstract/OtherAbstract:
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Purpose: This study aims to demonstrate, using human cadavers the feasibility of energy-based adaptive focusing of ultrasonic waves using magnetic resonance acoustic radiation force imaging (MR-ARFI) in the framework of non-invasive transcranial high intensity focused ultrasound (HIFU) therapy.Methods: Energy-based adaptive focusing techniques were recently proposed in order to achieve aberration correction. The authors evaluate this method on a clinical brain HIFU system composed of 512 ultrasonic elements positioned inside a full body 1.5 T clinical magnetic resonance (MR) imaging system. Cadaver heads were mounted onto a clinical Leksell stereotactic frame. The ultrasonic wave intensity at the chosen location was indirectly estimated by the MR system measuring the local tissue displacement induced by the acoustic radiation force of the ultrasound (US) beams. For aberration correction, a set of spatially encoded ultrasonic waves was transmitted from the ultrasonic array and the resulting local displacements were estimated with the MR-ARFI sequence for each emitted beam. A noniterative inversion process was then performed in order to estimate the spatial phase aberrations induced by the cadaver skull. The procedure was first evaluated and optimized in a calf brain using a numerical aberrator mimicking human skull aberrations. The full method was then demonstrated using a fresh human cadaver head.Results: The corrected beam resulting from the direct inversion process was found to focus at the targeted location with an acoustic intensity 2.2 times higher than the conventional non corrected beam. In addition, this corrected beam was found to give an acoustic intensity 1.5 times higher than the focusing pattern obtained with an aberration correction using transcranial acoustic simulation-based on X-ray computed tomography (CT) scans.Conclusions: The proposed technique achieved near optimal focusing in an intact human head for the first time. These findings confirm the strong potential of energy-based adaptive focusing of transcranial ultrasonic beams for clinical applications. |
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Authors:
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L Marsac; D Chauvet; B Larrat; M Pernot; B Robert; M Fink; A L Boch; J F Aubry; M Tanter |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Medical physics Volume: 39 ISSN: 0094-2405 ISO Abbreviation: Med Phys Publication Date: 2012 Feb |
Date Detail:
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Created Date: 2012-02-10 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0425746 Medline TA: Med Phys Country: United States |
Other Details:
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Languages: eng Pagination: 1141 Citation Subset: IM |
Affiliation:
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Institut Langevin, ESPCI ParisTech, CNRS, INSERM, Université Paris 7, Paris 75005, France and SuperSonic Imagine, Aix en Provence 13857, France. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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