{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T07:11:50Z","timestamp":1771485110017,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2022,8,30]],"date-time":"2022-08-30T00:00:00Z","timestamp":1661817600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001665","name":"CNRS","doi-asserted-by":"publisher","award":["ANR-11-INBS-0006"],"award-info":[{"award-number":["ANR-11-INBS-0006"]}],"id":[{"id":"10.13039\/501100001665","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001665","name":"CNRS","doi-asserted-by":"publisher","award":["801305"],"award-info":[{"award-number":["801305"]}],"id":[{"id":"10.13039\/501100001665","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001665","name":"CNRS","doi-asserted-by":"publisher","award":["68335"],"award-info":[{"award-number":["68335"]}],"id":[{"id":"10.13039\/501100001665","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000780","name":"European Union","doi-asserted-by":"publisher","award":["ANR-11-INBS-0006"],"award-info":[{"award-number":["ANR-11-INBS-0006"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000780","name":"European Union","doi-asserted-by":"publisher","award":["801305"],"award-info":[{"award-number":["801305"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000780","name":"European Union","doi-asserted-by":"publisher","award":["68335"],"award-info":[{"award-number":["68335"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Photoacoustic (PA) imaging systems are spreading in the biomedical community, and the development of new PA contrast agents is an active area of research. However, PA contrast agents are usually characterized with spectrophotometry or uncalibrated PA imaging systems, leading to partial assessment of their PA efficiency. To enable quantitative PA spectroscopy of contrast agents in vitro with conventional PA imaging systems, we have developed an adapted calibration method. Contrast agents in solution are injected in a dedicated non-scattering tube phantom imaged at different optical wavelengths. The calibration method uses a reference solution of cupric sulfate to simultaneously correct for the spectral energy distribution of excitation light at the tube location and perform a conversion of the tube amplitude in the image from arbitrary to spectroscopic units. The method does not require any precise alignment and provides quantitative PA spectra, even with non-uniform illumination and ultrasound sensitivity. It was implemented on a conventional imaging setup based on a tunable laser operating between 680 nm and 980 nm and a 5 MHz clinical ultrasound array. We demonstrated robust calibrated PA spectroscopy with sample volumes as low as 15 \u03bcL of known chromophores and commonly used contrast agents. The validated method will be an essential and accessible tool for the development of new and efficient PA contrast agents by improving their quantitative characterization.<\/jats:p>","DOI":"10.3390\/s22176543","type":"journal-article","created":{"date-parts":[[2022,8,31]],"date-time":"2022-08-31T00:13:56Z","timestamp":1661904836000},"page":"6543","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Calibrated Photoacoustic Spectrometer Based on a Conventional Imaging System for In Vitro Characterization of Contrast Agents"],"prefix":"10.3390","volume":"22","author":[{"given":"Th\u00e9otim","family":"Lucas","sequence":"first","affiliation":[{"name":"Laboratoire d\u2019Imagerie Biom\u00e9dicale, Sorbonne Universit\u00e9, CNRS, INSERM, LIB, 75006 Paris, France"},{"name":"Mati\u00e8re et Syst\u00e8mes Complexes, Universit\u00e9 Paris Cit\u00e9, CNRS, MSC, 75006 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3431-0678","authenticated-orcid":false,"given":"Mitradeep","family":"Sarkar","sequence":"additional","affiliation":[{"name":"Paris Cardiovascular Research Center, Universit\u00e9 Paris Cit\u00e9, INSERM, PARCC, 75015 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoann","family":"Atlas","sequence":"additional","affiliation":[{"name":"Laboratoire d\u2019Imagerie Biom\u00e9dicale, Sorbonne Universit\u00e9, CNRS, INSERM, LIB, 75006 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cl\u00e9ment","family":"Linger","sequence":"additional","affiliation":[{"name":"Laboratoire d\u2019Imagerie Biom\u00e9dicale, Sorbonne Universit\u00e9, CNRS, INSERM, LIB, 75006 Paris, France"},{"name":"Institut Galien Paris-Saclay, Universit\u00e9 Paris-Saclay, CNRS, IGPS, 91400 Orsay, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2273-1229","authenticated-orcid":false,"given":"Gilles","family":"Renault","sequence":"additional","affiliation":[{"name":"Institut Cochin, Universit\u00e9 Paris Cit\u00e9, INSERM, CNRS, 75014 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Florence","family":"Gazeau","sequence":"additional","affiliation":[{"name":"Mati\u00e8re et Syst\u00e8mes Complexes, Universit\u00e9 Paris Cit\u00e9, CNRS, MSC, 75006 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5230-8988","authenticated-orcid":false,"given":"J\u00e9r\u00f4me","family":"Gateau","sequence":"additional","affiliation":[{"name":"Laboratoire d\u2019Imagerie Biom\u00e9dicale, Sorbonne Universit\u00e9, CNRS, INSERM, LIB, 75006 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"602","DOI":"10.1098\/rsfs.2011.0028","article-title":"Biomedical photoacoustic imaging","volume":"1","author":"Beard","year":"2011","journal-title":"Interface Focus"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1038\/nphoton.2015.29","article-title":"Advances in real-time multispectral optoacoustic imaging and its applications","volume":"9","author":"Taruttis","year":"2015","journal-title":"Nat. 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