title: Pixel based focusing for photoacoustic and ultrasound dual-modality imaging.
abstract: It is desired that the same imaging functional modules such as beamformation, envelope detection, and digital scan conversion (DSC) are employed for the efficient development of a cross-sectional photoacoustic (PA) and ultrasound (US) dual-modality imaging system. The beamformation can be implemented using either delay-and-sum beamforming (DAS-BF) or adaptive beamforming methods, each with their own advantages and disadvantages for the dual-modality imaging. However, the DSC is always problematic because it causes blurring the fine details of an image, e.g., edges. This paper demonstrates that the pixel based focusing method is suitable for the dual-modality imaging; beamformation is directly conducted on each display pixel and thus DSC is not necessary. As a result, the artifacts by DSC are no longer a problem, so that the proposed method is capable of providing the maximum spatial resolution achievable by DAS-BF. The performance of the proposed method was evaluated through simulation and ex vivo experiments with a microcalcification-contained breast specimen, and the results were compared with those from DAS-BF and adaptive beamforming methods with DSC. The comparison demonstrated that the proposed method effectively overcomes the disadvantages of each beamforming method.
authors.affiliation: Department of Electronic Engineering, Sogang University, Seoul, Republic of Korea.
authors.forename: Changhan
authors.initials: C
authors.lastname: Yoon
authors.affiliation: Department of Electronic Engineering, Sogang University, Seoul, Republic of Korea; Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul, Republic of Korea.
authors.forename: Yangmo
authors.initials: Y
authors.lastname: Yoo
authors.affiliation: Department of Electronic Engineering, Sogang University, Seoul, Republic of Korea.
authors.forename: Tai-Kyong
authors.initials: TK
authors.lastname: Song
authors.affiliation: Department of Electronic Engineering, Sogang University, Seoul, Republic of Korea; Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul, Republic of Korea; Sogang Institute of Advanced Technology, Sogang University, Seoul, Republic of Korea. Electronic address: jhchang@sogang.ac.kr.
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Chang
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001706:Biopsy; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D014463:Ultrasonography / Q000379:methods*; D016217:Ultrasonography, Mammary / Q000379:methods*
keywords: Dual-modality imaging; Photoacoustic imaging; Pixel based focusing; Scan conversion; Ultrasound imaging