title: Passive acoustic mapping utilizing optimal beamforming in ultrasound therapy monitoring.
abstract: Passive acoustic mapping (PAM) is a promising imaging method that enables real-time three-dimensional monitoring of ultrasound therapy through the reconstruction of acoustic emissions passively received on an array of ultrasonic sensors. A passive beamforming method is presented that provides greatly improved spatial accuracy over the conventionally used time exposure acoustics (TEA) PAM reconstruction algorithm. Both the Capon beamformer and the robust Capon beamformer (RCB) for PAM are suggested as methods to reduce interference artifacts and improve resolution, which has been one of the experimental issues previously observed with TEA. Simulation results that replicate the experimental artifacts are shown to suggest that bubble interactions are the chief cause. Analysis is provided to show that these multiple bubble artifacts are generally not reduced by TEA, while Capon-based methods are able to reduce the artifacts. This is followed by experimental results from in vitro experiments and in vivo oncolytic viral therapy trials that show improved results in PAM, where RCB is able to more accurately localize the acoustic activity than TEA.
authors.affiliation: Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: Coviello
authors.affiliation: Department of Electrical Engineering, Bucknell University, Lewisburg, Pennsylvania 17837, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Kozick
authors.affiliation: Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Choi
authors.affiliation: Faculty of Information and Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.
authors.forename: Miklós
authors.initials: M
authors.lastname: Gyöngy
authors.affiliation: Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom.
authors.forename: Carl
authors.initials: C
authors.lastname: Jensen
authors.affiliation: Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom.
authors.forename: Penny Probert
authors.initials: PP
authors.lastname: Smith
authors.affiliation: Institute of Biomedical Engineering, University of Oxford, Oxford OX3 7DQ, United Kingdom.
authors.forename: Constantin-C
authors.initials: CC
authors.lastname: Coussios