Suchergebnisse

[EN] Acoustic vortex beams have great potential for contactless particle manipulation and torque-based biomedical applications. However, when focusing acoustic waves through aberration layers such as the human skull at ultrasonic frequencies results in strong phase aberrations which prevent the generation of sharp acoustic images. In the case of a wavefront containing phase dislocations, skull aberrations inhibit the focusing of acoustic vortex beams inside the cranial cavity. In this work, we demonstrate that phase-conjugated acoustic holograms can encode time-reversed fields simultaneously allowing the compensation of the aberrations of the skull and the generation of a focused vortex inside an ex-vivo human skull. The method is applied for single-element geometrically focused sources and results in a very simple and compact ultrasonic system. This work will pave the road to design low-cost particle trapping applications, clot manipulation, torque exertion in the brain and acoustic-radiation-force based biomedical applications. ; This research was supported by the Spanish Ministry of Science, Innovation, and Universities through "Juan de la Cierva-Incorporacion" Grants No. IJC2018-037897-I and No. PID2019-111436RB-C22, by the Agencia Valenciana de la Innovacio through Grants No. INNVAL10/19/016, No. INNVA1/2020/92, and No. INNCON/2020/009, and by the Generalitat Valenciana through Grant No. ACIF/2017/045. The action was cofinanced by the European Union through the Programa Operativo del Fondo Europeo de Desarrollo Regional (FEDER) of the Comunitat Valenciana, Grant No. IDIFEDER/2018/022. ; Jiménez-Gambín, S.; Jimenez, N.; Camarena Femenia, F. (2020). Transcranial focusing of ultrasonic vortices by acoustic holograms. Physical Review Applied. 14(5):1-10. https://doi.org/10.1103/PhysRevApplied.14.054070 ; S ; 1 ; 10 ; 14 ; 5 ; Elias, W. J., Huss, D., Voss, T., Loomba, J., Khaled, M., Zadicario, E., … Wintermark, M. (2013). A Pilot Study of Focused Ultrasound Thalamotomy for Essential Tremor. New England Journal ...

[EN] Single-element focused ultrasound devices have demonstrated its ability to non-invasively open the Blood Brain Barrier. However, skull irregularities and absorption produce strong aberrations in the ultrasound focus. Recently, 3D-printed acoustic holograms were used to compensate aberrations and to produce a sharp focus. In addition, using this technology the geometry of the ultrasonic focus can be matched to the shape of the brain structure of interest. In this work, we experimentally and numerically report 3D-printed acoustic holograms for bilateral focusing through an ex-vivo human skull. Using holograms, we target different cerebral nuclei and the ultrasonic focuses are adapted to the target volumes, minimizing the acoustic field outside. Simultaneously, skull aberrations are corrected using phased-conjugation methods. The holographic surfaces were manufactured for a 100-mm aperture and 140-mm focal focused transducer at 500 kHz to focus through an ex-vivo human skull. Numerical and experimental results agree targeting several deep-brain nuclei: left-and-right putamen, caudate nuclei, and hippocampi, showing the potential of this low-cost technology to optimize BBBO or neuromodulation treatments. ; This research has been supported by the Spanish Ministry of Science, Innovation and Universities through grant Juan de la Cierva - Incorporacion (IJC2018-037897-I) and PID2019-111436RBC22, by the Agencia Valenciana de la Innovacio through grants INNVAL10/19/016 and INNCON/2020/009. Action cofinanced by the European Union through the Programa Operativo del Fondo Europeo de Desarrollo Regional (FEDER) of the Comunitat Valenciana 2014-2020 (IDIFEDER/2018/022). ; Andrés, D.; Jiménez-Gambín, S.; Jimenez, N.; Camarena Femenia, F. (2020). Multifocal acoustic holograms for deep-brain neuromodulation and BBB opening. IEEE. 1-3. https://doi.org/10.1109/IUS46767.2020.9251769 ; S ; 1 ; 3