{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,1]],"date-time":"2025-11-01T12:57:47Z","timestamp":1762001867873,"version":"build-2065373602"},"reference-count":23,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2018,10,17]],"date-time":"2018-10-17T00:00:00Z","timestamp":1539734400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100010663","name":"H2020 European Research Council","doi-asserted-by":"publisher","award":["2015-StG-37960"],"award-info":[{"award-number":["2015-StG-37960"]}],"id":[{"id":"10.13039\/100010663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Imaging"],"abstract":"<jats:p>Reconstruction of photoacoustic (PA) images acquired with clinical ultrasound transducers is usually performed using the Delay and Sum (DAS) beamforming algorithm. Recently, a variant of DAS, referred to as Delay Multiply and Sum (DMAS) beamforming has been shown to provide increased contrast, signal-to-noise ratio (SNR) and resolution in PA imaging. The main reasons for the use of DAS beamforming in photoacoustics are its simple implementation, real-time capability, and the linearity of the beamformed image to the PA signal. This is crucial for the identification of different chromophores in multispectral PA applications. In contrast, current DMAS implementations are not responsive to the full spectrum of sound frequencies from a photoacoustic source and have not been shown to provide a reconstruction linear to the PA signal. Furthermore, due to its increased computational complexity, DMAS has not been shown yet to work in real-time. Here, we present an open-source real-time variant of the DMAS algorithm, signed DMAS (sDMAS), that ensures linearity in the original PA signal response while providing the increased image quality of DMAS. We show the applicability of sDMAS for multispectral PA applications, in vitro and in vivo. The sDMAS and reference DAS algorithms were integrated in the open-source Medical Imaging Interaction Toolkit (MITK) and are available as real-time capable implementations.<\/jats:p>","DOI":"10.3390\/jimaging4100121","type":"journal-article","created":{"date-parts":[[2018,10,17]],"date-time":"2018-10-17T10:22:54Z","timestamp":1539771774000},"page":"121","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":39,"title":["Signed Real-Time Delay Multiply and Sum Beamforming for Multispectral Photoacoustic Imaging"],"prefix":"10.3390","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3819-1987","authenticated-orcid":false,"given":"Thomas","family":"Kirchner","sequence":"first","affiliation":[{"name":"Division of Computer Assisted Medical Interventions (CAMI), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany"},{"name":"Faculty of Physics and Astronomy, Heidelberg University, 69120 Heidelberg, Germany"}]},{"given":"Franz","family":"Sattler","sequence":"additional","affiliation":[{"name":"Division of Computer Assisted Medical Interventions (CAMI), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany"},{"name":"Faculty of Physics and Astronomy, Heidelberg University, 69120 Heidelberg, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5332-4856","authenticated-orcid":false,"given":"Janek","family":"Gr\u00f6hl","sequence":"additional","affiliation":[{"name":"Division of Computer Assisted Medical Interventions (CAMI), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany"},{"name":"Medical Faculty, Heidelberg University, 69120 Heidelberg, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4910-9368","authenticated-orcid":false,"given":"Lena","family":"Maier-Hein","sequence":"additional","affiliation":[{"name":"Division of Computer Assisted Medical Interventions (CAMI), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany"},{"name":"Medical Faculty, Heidelberg University, 69120 Heidelberg, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2018,10,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1109\/TAP.1982.1142739","article-title":"An alternative approach to linearly constrained adaptive beamforming","volume":"30","author":"Griffiths","year":"1982","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Kim, J., Park, S., Jung, Y., Chang, S., Park, J., Zhang, Y., Lovell, J.F., and Kim, C. (2016). Programmable real-time clinical photoacoustic and ultrasound imaging system. Sci. Rep., 6.","DOI":"10.1038\/srep35137"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1109\/TBME.2017.2690959","article-title":"Double Stage Delay Multiply and Sum Beamforming Algorithm: Application to Linear-Array Photoacoustic Imaging","volume":"65","author":"Mozaffarzadeh","year":"2017","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"940","DOI":"10.1109\/TMI.2014.2371235","article-title":"The Delay Multiply and Sum Beamforming Algorithm in Ultrasound B-Mode Medical Imaging","volume":"34","author":"Matrone","year":"2015","journal-title":"IEEE Trans. Med. Imag."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Park, J., Jeon, S., Meng, J., Song, L., Lee, J.S., and Kim, C. (2016). Delay-multiply-and-sum-based synthetic aperture focusing in photoacoustic microscopy. J. Biomed. Opt., 21.","DOI":"10.1117\/1.JBO.21.3.036010"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"478","DOI":"10.1109\/TMI.2016.2615069","article-title":"High Frame-Rate, High Resolution Ultrasound Imaging with Multi-Line Transmission and Filtered-Delay Multiply and Sum Beamforming","volume":"36","author":"Matrone","year":"2017","journal-title":"IEEE Trans. Med. Imag."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Alshaya, A., Harput, S., Moubark, A.M., Cowell, D.M., McLaughlan, J., and Freear, S. (2016, January 18\u201321). Spatial resolution and contrast enhancement in photoacoustic imaging with filter delay multiply and sum beamforming technique. Proceedings of the 2016 IEEE International Ultrasonics Symposium (IUS), Tours, France.","DOI":"10.1109\/ULTSYM.2016.7728682"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Treeby, B.E., Zhang, E.Z., and Cox, B.T. (2010). Photoacoustic tomography in absorbing acoustic media using time reversal. Inverse Prob., 26.","DOI":"10.1088\/0266-5611\/26\/11\/115003"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"607","DOI":"10.1007\/s11548-013-0840-8","article-title":"The Medical Imaging Interaction Toolkit: Challenges and advances","volume":"8","author":"Nolden","year":"2013","journal-title":"Int. J. Comput. Assist. Radiol. Surg."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"314","DOI":"10.1109\/TUFFC.2009.1040","article-title":"Broadband minimum variance beamforming for ultrasound imaging","volume":"56","author":"Holfort","year":"2009","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Xu, G., Dar, I.A., Tao, C., Liu, X., Deng, C.X., and Wang, X. (2012). Photoacoustic spectrum analysis for microstructure characterization in biological tissue: A feasibility study. Appl. Phys. Lett., 101.","DOI":"10.1063\/1.4768703"},{"key":"ref_12","first-page":"777","article-title":"An introduction to the opencl programming model","volume":"49","author":"Tompson","year":"2012","journal-title":"Pers. Educ."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1109\/PROC.1978.10837","article-title":"On the use of windows for harmonic analysis with the discrete Fourier transform","volume":"66","author":"Harris","year":"1978","journal-title":"Proc. IEEE"},{"key":"ref_14","unstructured":"Laser Institute of America (2007). American National Standard for Safe Use of Lasers, Laser Institute of America."},{"key":"ref_15","unstructured":"Kirchner, T., Sattler, F., Dinkelacker, S., Goch, C.J., Gr\u00f6hl, J., Nolden, M., and Maier-Hein, L. (2018, September 11). MITK\/MITK: sDMAS-2018.07. Available online: https:\/\/zenodo.org\/record\/1303376#.W7_9blL3McU."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Jacques, S.L. (2013). Optical properties of biological tissues: A review. Phys. Med. Biol., 58.","DOI":"10.1088\/0031-9155\/58\/11\/R37"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"510","DOI":"10.1002\/lsm.1900120510","article-title":"Optical properties of intralipid: A phantom medium for light propagation studies","volume":"12","author":"Flock","year":"1992","journal-title":"Lasers Surg. Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1371\/journal.pone.0077089","article-title":"On the Definition of Signal-To-Noise Ratio and Contrast-To-Noise Ratio for fMRI Data","volume":"8","author":"Welvaert","year":"2013","journal-title":"PLoS ONE"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"187","DOI":"10.3109\/00365519009087509","article-title":"The oxygen status of arterial human blood","volume":"50","author":"Zander","year":"1990","journal-title":"Scand. J. Clin. Lab. Investig."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.pacs.2013.08.001","article-title":"Optical wavelength selection for improved spectroscopic photoacoustic imaging","volume":"1","author":"Luke","year":"2013","journal-title":"Photoacoustics"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Lawson, C.L., and Hanson, R.J. (1995). Solving Least Squares Problems, SIAM.","DOI":"10.1137\/1.9781611971217"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Mozaffarzadeh, M., Mahloojifar, A., Orooji, M., Kratkiewicz, K., Adabi, S., and Nasiriavanaki, M. (2018). Linear-array photoacoustic imaging using minimum variance-based delay multiply and sum adaptive beamforming algorithm. J. Biomed. Opt., 23.","DOI":"10.1117\/1.JBO.23.2.026002"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"056008","DOI":"10.1117\/1.JBO.23.5.056008","article-title":"Context encoding enables machine learning-based quantitative photoacoustics","volume":"23","author":"Kirchner","year":"2018","journal-title":"J. Biomed. 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