@article{discovery10151769,
          volume = {27},
           month = {July},
       publisher = {SPIE-Intl Soc Optical Eng},
         journal = {Journal of Biomedical Optics},
          number = {7},
            year = {2022},
           title = {Multi-laboratory performance assessment of diffuse optics instruments: the BitMap exercise},
            note = {{\copyright} The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).},
        keywords = {absorption, diffuse optics, near-infrared spectroscopy, phantom, scattering, Laboratories, Optics and Photonics, Phantoms, Imaging, Reproducibility of Results, Spectrum Analysis},
             url = {https://doi.org/10.1117/1.JBO.27.7.074716},
        abstract = {SIGNIFICANCE: Multi-laboratory initiatives are essential in performance assessment and standardization-crucial for bringing biophotonics to mature clinical use-to establish protocols and develop reference tissue phantoms that all will allow universal instrument comparison. AIM: The largest multi-laboratory comparison of performance assessment in near-infrared diffuse optics is presented, involving 28 instruments and 12 institutions on a total of eight experiments based on three consolidated protocols (BIP, MEDPHOT, and NEUROPT) as implemented on three kits of tissue phantoms. A total of 20 synthetic indicators were extracted from the dataset, some of them defined here anew. APPROACH: The exercise stems from the Innovative Training Network BitMap funded by the European Commission and expanded to include other European laboratories. A large variety of diffuse optics instruments were considered, based on different approaches (time domain/frequency domain/continuous wave), at various stages of maturity and designed for different applications (e.g., oximetry, spectroscopy, and imaging). RESULTS: This study highlights a substantial difference in hardware performances (e.g., nine decades in responsivity, four decades in dark count rate, and one decade in temporal resolution). Agreement in the estimates of homogeneous optical properties was within 12\% of the median value for half of the systems, with a temporal stability of {\ensuremath{<}}5  \%   over 1 h, and day-to-day reproducibility of {\ensuremath{<}}3  \%  . Other tests encompassed linearity, crosstalk, uncertainty, and detection of optical inhomogeneities. CONCLUSIONS: This extensive multi-laboratory exercise provides a detailed assessment of near-infrared Diffuse optical instruments and can be used for reference grading. The dataset-available soon in an open data repository-can be evaluated in multiple ways, for instance, to compare different analysis tools or study the impact of hardware implementations.},
          author = {Lanka, Pranav and Yang, Lin and Orive-Miguel, David and Veesa, Joshua Deepak and Tagliabue, Susanna and Sudakou, Aleh and Samaei, Saeed and Forcione, Mario and Kovacsova, Zuzana and Behera, Anurag and Gladytz, Thomas and Grosenick, Dirk and Herv{\'e}, Lionel and Durduran, Turgut and Bejm, Karolina and Morawiec, Magdalena and Kacprzak, Micha{\l} and Sawosz, Piotr and Gerega, Anna and Liebert, Adam and Belli, Antonio and Tachtsidis, Ilias and Lange, Fr{\'e}d{\'e}ric and Bale, Gemma and Baratelli, Luca and Gioux, Sylvain and Alexander, Kalyanov and Wolf, Martin and Sekar, Sanathana Konugolu Venkata and Zanoletti, Marta and Pirovano, Ileana and Lacerenza, Michele and Qiu, Lina and Ferocino, Edoardo and Maffeis, Giulia and Amendola, Caterina and Colombo, Lorenzo and Frabasile, Lorenzo and Levoni, Pietro and Buttafava, Mauro and Renna, Marco and Di Sieno, Laura and Re, Rebecca and Farina, Andrea and Spinelli, Lorenzo and Dalla Mora, Alberto and Contini, Davide and Taroni, Paola and Tosi, Alberto and Torricelli, Alessandro and Dehghani, Hamid and Wabnitz, Heidrun and Pifferi, Antonio}
}