{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T10:56:08Z","timestamp":1761648968085,"version":"build-2065373602"},"reference-count":35,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,12,24]],"date-time":"2021-12-24T00:00:00Z","timestamp":1640304000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003329","name":"Ministry of Economy, Industry and Competitiveness","doi-asserted-by":"publisher","award":["RTI2018-097088-B-C31"],"award-info":[{"award-number":["RTI2018-097088-B-C31"]}],"id":[{"id":"10.13039\/501100003329","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000006","name":"Office of Naval Research","doi-asserted-by":"publisher","award":["N00014-19-1-2156"],"award-info":[{"award-number":["N00014-19-1-2156"]}],"id":[{"id":"10.13039\/100000006","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000781","name":"European Research Council","doi-asserted-by":"publisher","award":["695536"],"award-info":[{"award-number":["695536"]}],"id":[{"id":"10.13039\/501100000781","id-type":"DOI","asserted-by":"publisher"}]},{"name":"EU H2020 MSCA through Project ACHIEVE-ITN","award":["765866"],"award-info":[{"award-number":["765866"]}]},{"DOI":"10.13039\/501100003359","name":"Generalitat Valenciana","doi-asserted-by":"publisher","award":["APOSTD\/2019\/086"],"award-info":[{"award-number":["APOSTD\/2019\/086"]}],"id":[{"id":"10.13039\/501100003359","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Silicon photomultipliers (SiPMs) are arrays of single-photon avalanche diodes (SPADs) connected in parallel. Analog silicon photomultipliers are built in custom technologies optimized for detection efficiency. Digital silicon photomultipliers are built in CMOS technology. Although CMOS SPADs are less sensitive, they can incorporate additional functionality at the sensor plane, which is required in some applications for an accurate detection in terms of energy, timestamp, and spatial location. This additional circuitry comprises active quenching and recharge circuits, pulse combining and counting logic, and a time-to-digital converter. This, together with the disconnection of defective SPADs, results in a reduction of the light-sensitive area. In addition, the pile-up of pulses, in space and in time, translates into additional efficiency losses that are inherent to digital SiPMs. The design of digital SiPMs must include some sort of optimization of the pixel architecture in order to maximize sensitivity. In this paper, we identify the most relevant variables that determine the influence of SPAD yield, fill factor loss, and spatial and temporal pile-up in the photon detection efficiency. An optimum of 8% is found for different pixel sizes. The potential benefits of molecular imaging of these optimized and small-sized pixels with independent timestamping capabilities are also analyzed.<\/jats:p>","DOI":"10.3390\/s22010122","type":"journal-article","created":{"date-parts":[[2021,12,27]],"date-time":"2021-12-27T01:06:54Z","timestamp":1640567214000},"page":"122","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Architecture-Level Optimization on Digital Silicon Photomultipliers for Medical Imaging"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5940-2544","authenticated-orcid":false,"given":"Franco","family":"Bandi","sequence":"first","affiliation":[{"name":"Organisation Europ\u00e9enne Pour la Recherche Nucl\u00e9aire, Experimental Physics Department, Esplanade des Particules 1, 1211 Meyrin, Switzerland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8097-3539","authenticated-orcid":false,"given":"Victor","family":"Ilisie","sequence":"additional","affiliation":[{"name":"Escuela de Ciencias, Ingenier\u00eda y Dise\u00f1o, Universidad Europea de Valencia, Passeig de l\u2019Albereda, 7, 46010 Valencia, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6865-5116","authenticated-orcid":false,"given":"Ion","family":"Vornicu","sequence":"additional","affiliation":[{"name":"Silicon Austria Labs, Frontend Integrated Circuits & Systems and RF Systems, Europastra\u00dfe 12, 9524 Villach, Austria"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4230-3988","authenticated-orcid":false,"given":"Ricardo","family":"Carmona-Gal\u00e1n","sequence":"additional","affiliation":[{"name":"Instituto de Microelectr\u00f3nica de Sevilla (IMSE-CNM), CSIC-Universidad de Sevilla, 41092 Sevilla, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6073-1436","authenticated-orcid":false,"given":"Jos\u00e9 M.","family":"Benlloch","sequence":"additional","affiliation":[{"name":"Institute for Instrumentation in Molecular Imaging (I3M), CSIC-Universitat Polit\u00e8cnica de Val\u00e8ncia, 46022 Valencia, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1006-5241","authenticated-orcid":false,"given":"\u00c1ngel","family":"Rodr\u00edguez-V\u00e1zquez","sequence":"additional","affiliation":[{"name":"Instituto de Microelectr\u00f3nica de Sevilla (IMSE-CNM), CSIC-Universidad de Sevilla, 41092 Sevilla, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1016\/j.phpro.2012.02.358","article-title":"Upgrade of the CMS Hadron Outer Calorimeter with SIPMs","volume":"37","author":"Anderson","year":"2012","journal-title":"Phys. Procedia"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"352","DOI":"10.1016\/j.nima.2013.07.068","article-title":"Beam test of FARICH prototype with digital photon counter","volume":"732","author":"Barnyakov","year":"2013","journal-title":"Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrom. Detect. Assoc. Equip."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Hirose, Y., Koyama, S., Ishii, M., Saitou, S., Takemoto, M., Nose, Y., Inoue, A., Sakata, Y., Sugiura, Y., and Kabe, T. (2018). A 250 m Direct Time-of-Flight Ranging System Based on a Synthesis of Sub-Ranging Images and a Vertical Avalanche Photo-Diodes (VAPD) CMOS Image Sensor. Sensors, 18.","DOI":"10.3390\/s18113642"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3789","DOI":"10.1109\/JSEN.2018.2813531","article-title":"A 16 \u00d7 256 SPAD Line Detector with a 50-ps, 3-bit, 256-Channel Time-to-Digital Converter for Raman Spectroscopy","volume":"18","author":"Nissinen","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"562","DOI":"10.1109\/TBCAS.2012.2222639","article-title":"A High-Throughput Time-Resolved Mini-Silicon Photomultiplier With Embedded Fluorescence Lifetime Estimation in 0.13 \u03bcm CMOS","volume":"6","author":"Tyndall","year":"2012","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1705","DOI":"10.1109\/JSSC.2019.2894355","article-title":"A CMOS SPAD Line Sensor with Per-Pixel Histogramming TDC for Time-Resolved Multispectral Imaging","volume":"54","author":"Erdogan","year":"2019","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_7","unstructured":"Frach, T., Prescher, G., Degenhardt, C., de Gruyter, R., Schmitz, A., and Ballizany, R. (November, January 24). The digital silicon photomultiplier Principle of operation and intrinsic detector performance. Proceedings of the Nuclear Science Symposium Conference Record (NSS\/MIC), Orlando, FL, USA."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1109\/JSSC.2013.2284351","article-title":"A Fully Digital 8 \u00d7 16 SiPM Array for PET Applications With Per-Pixel TDCs and Real-Time Energy Output","volume":"49","author":"Braga","year":"2014","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_9","unstructured":"Mandai, S. (2014). Multichannel Digital Silicon Photomultiplier for Time-of-Flight PET. [Ph.D. Thesis, Delft University of Technology]."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Moreno-Garc\u00eda, M., Xu, H., Gasparini, L., and Perenzoni, M. (2018, January 3\u20136). Low-Noise Single Photon Avalanche Diodes in a 110 nm CIS Technology. Proceedings of the 2018 48th European Solid-State Device Research Conference (ESSDERC), Dresden, Germany.","DOI":"10.1109\/ESSDERC.2018.8486883"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2028","DOI":"10.1109\/TED.2011.2141138","article-title":"Scaleable Single-Photon Avalanche Diode Structures in Nanometer CMOS Technology","volume":"58","author":"Richardson","year":"2011","journal-title":"IEEE Trans. Electron Devices"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"12817","DOI":"10.1109\/JSEN.2020.3002609","article-title":"Compact Macro-Cell With OR Pulse Combining for Low Power Digital-SiPM","volume":"20","author":"Vornicu","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2471","DOI":"10.1109\/TNS.2016.2522179","article-title":"A PET Design Based on SiPM and Monolithic LYSO Crystals: Performance Evaluation","volume":"63","author":"Aguilar","year":"2016","journal-title":"IEEE Trans. Nucl. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2375","DOI":"10.1088\/0031-9155\/56\/8\/004","article-title":"Physical and clinical performance of the mCT time-of-flight PET\/CT scanner","volume":"56","author":"Jakoby","year":"2011","journal-title":"Phys. Med. Biol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1016\/j.nima.2012.08.066","article-title":"Endo-TOFPET-US: A multimodal ultrasonic probe featuring time of flight PET in diagnostic and therapeutic endoscopy","volume":"718","author":"Meyer","year":"2013","journal-title":"Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrom. Detect. Assoc. Equip."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"561","DOI":"10.2967\/jnumed.118.215541","article-title":"Performance Evaluation of the Vereos PET\/CT System According to the NEMA NU2-2012 Standard","volume":"60","author":"Rausch","year":"2019","journal-title":"J. Nucl. Med."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"144","DOI":"10.2967\/jnumed.119.231845","article-title":"PennPET Explorer: Human Imaging on a Whole-Body Imager","volume":"61","author":"Pantel","year":"2020","journal-title":"J. Nucl. Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"051906","DOI":"10.1118\/1.4800798","article-title":"ALBIRA: A small animal PET\/SPECT\/CT imaging system","volume":"40","author":"Orero","year":"2013","journal-title":"Med. Phys."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1130","DOI":"10.2967\/jnumed.115.165886","article-title":"A Prototype High-Resolution Small-Animal PET Scanner Dedicated to Mouse Brain Imaging","volume":"57","author":"Yang","year":"2016","journal-title":"J. Nucl. Med."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"462","DOI":"10.2967\/jnumed.107.044834","article-title":"The benefit of time-of-flight in PET imaging: Experimental and clinical results","volume":"49","author":"Karp","year":"2009","journal-title":"J. Nucl. Med."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1016\/j.nima.2018.03.076","article-title":"Building blocks of a multi-layer PET with time sequence photon interaction discrimination and double Compton camera","volume":"895","author":"Ilisie","year":"2018","journal-title":"Nucl. Instrum. Methods Phys. Res. A"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"S208","DOI":"10.1016\/j.nima.2010.04.111","article-title":"Development of large-area silicon photomultiplier detectors for PET applications at FBK","volume":"636","author":"Zorzi","year":"2011","journal-title":"Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrom. Detect. Assoc. Equip."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2549","DOI":"10.1109\/TNS.2010.2064788","article-title":"System Tradeoffs in Gamma-Ray Detection Utilizing SPAD Arrays and Scintillators","volume":"57","author":"Fishburn","year":"2010","journal-title":"IEEE Trans. Nucl. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"925","DOI":"10.1109\/TNS.2017.2665878","article-title":"TDC Array Tradeoffs in Current and Upcoming Digital SiPM Detectors for Time-of-Flight PET","volume":"64","author":"Therrien","year":"2017","journal-title":"IEEE Trans. Nucl. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Braga, L.H.C., Pancheri, L., Gasparini, L., Perenzoni, M., Walker, R., Henderson, R.K., and Stoppa, D. (2011, January 23\u201329). A CMOS mini-SiPM detector with in-pixel data compression for PET applications. Proceedings of the 2011 IEEE Nuclear Science Symposium Conference Record, Valencia, Spain.","DOI":"10.1109\/NSSMIC.2011.6154110"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"250","DOI":"10.1016\/S0168-9002(03)01368-8","article-title":"Geant4 a simulation toolkit","volume":"506","author":"Agostinelli","year":"2003","journal-title":"Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrom. Detect. Assoc. Equip."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4543","DOI":"10.1088\/0031-9155\/49\/19\/007","article-title":"GATE: A simulation toolkit for PET and SPECT","volume":"49","author":"Jan","year":"2004","journal-title":"Phys. Med. Biol."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Arce, P., Rato, P., Canadas, M., and Lagares, J.I. (2008, January 19\u201325). GAMOS: A Geant4-based easy and flexible framework for nuclear medicine applications. Proceedings of the 2008 IEEE Nuclear Science Symposium Conference Record, Dresden, Germany.","DOI":"10.1109\/NSSMIC.2008.4775023"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"473","DOI":"10.1109\/TRPMS.2017.2756674","article-title":"Pushing the Limits in Time-of-Flight PET Imaging","volume":"1","author":"Lecoq","year":"2017","journal-title":"IEEE Trans. Radiat. Plasma Med. Sci."},{"key":"ref_30","unstructured":"Bandi, F. (2020). Design of CMOS Digital Silicon Photomultipliers with TOF for Positron Emission Tomography. [Ph.D. Thesis, University of Seville]."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"4776","DOI":"10.1109\/JSEN.2020.3032106","article-title":"Design of High-Efficiency SPADs for LiDAR Applications in 110nm CIS Technology","volume":"21","author":"Vornicu","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Sze, S.M., and Kwok, K.N. (2006). p-n Junctions. Physics of Semiconductor Devices, John Wiley and Sons, Ltd.","DOI":"10.1002\/0470068329"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4014","DOI":"10.1109\/TED.2013.2285163","article-title":"A TCAD and Spectroscopy Study of Dark Count Mechanisms in Single-Photon Avalanche Diodes","volume":"60","author":"Webster","year":"2013","journal-title":"IEEE Trans. Electron Devices"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"971","DOI":"10.1140\/epjc\/s10052-018-6454-0","article-title":"Spatially resolved dark count rate of SiPMs","volume":"78","author":"Engelmann","year":"2018","journal-title":"Eur. Phys. J. C"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1797","DOI":"10.1088\/0031-9155\/57\/7\/1797","article-title":"The lower bound on the timing resolution of scintillation detectors","volume":"57","author":"Seifert","year":"2012","journal-title":"Phys. Med. Biol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/1\/122\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:53:16Z","timestamp":1760169196000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/1\/122"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,12,24]]},"references-count":35,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2022,1]]}},"alternative-id":["s22010122"],"URL":"https:\/\/doi.org\/10.3390\/s22010122","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2021,12,24]]}}}