Héctor García

Overview

Héctor is a physicist with biomedical optics and near infrared spectroscopy as main backgrounds. He spent the last few years modeling photon migration in tissue, both analytically and with numerical simulations, specially focusing on how tissue heterogeneity affects light propagation. He's also skilled in experimental techniques involving diffuse optical imaging and single photon counting. Now he is devoted to making use of all this to model and measure fluorescence, particularly by means of indocyanine green and Protoporphyrin IX, towards applications in fields such as fluorescence lifetime imaging and fluorescence-guided surgery.

Research Interests

Diffuse optical tomography; diffuse fluorescence tomography; functional near infrared spectroscopy; fluorescence-guided surgery; optical mammography

Education

• BSc, Physics, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Argentina 2012
• PhD, Physics, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Argentina 2017

Awards

• IOP Outstanding Reviewer Award, 2022
• Finalist in the Bernard Couillaud Award, 2022
• Physikalisch-Technische Bundesanstalt's Guest Researcher Programme (Berlin, Germany), 2018

Professional Activities

• Associate Professor at UNCPBA (Currently under a leave of absence)
• Research Scientist at the National Council of Technical and Scientific Research (CONICET), Argentina (Currently under a leave of absence)
• Member, Argentinian Physics Association (AFA)
• Member, SPIE
• Member, CNRS Alumni
• Member, IOP

Research Projects

• Exploring the role of oxygen in ultra high dose rate radiotherapy

  Exploring the role of oxygen in ultra high dose rate radiotherapy

  Ultra-high dose rate (UHDR) radiotherapy (RT) is an emerging cancer treatment that delivers high-energy beams (>40 Gy/s) to target tumors. Unlike conventional radiotherapy, which can damage healthy tissue, UHDR RT has been shown to spare normal tissue while maintaining tumor-killing effectiveness—a phenomenon known as the FLASH effect. The underlying mechanisms of this effect remain unclear. Our research focuses on investigating the role of oxygen in the FLASH effect using optical methods to measure tissue oxygen levels in real time during treatment.

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• Fluorescence-guided surgery

  Fluorescence-guided surgery

  Fluorescence-guided surgery is important for the resection of some types of cancerous tumors where the tumor and normal tissue are similar in appearance and texture, and patient prognosis depends heavily on the completeness of resection. By selectively tagging tumor tissue with fluorescent dyes, it becomes possible to visually discriminate between normal and tumor tissues and improve significantly the completeness of tumor resection.

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• Optical molecular imaging

  Optical molecular imaging

  Optical molecular imaging is being used to provide molecular guidance in cancer surgery. Fluorescent contrast agents are in pre-clinical and clinical studies to image cancer tumors in vivo, with a dual focus, first on getting more accurate information out of the tissue, and secondly to provide better information about the specificity of the molecules as markers. Systems and algorithms for diffuse fluorescence imaging of tissue are studied, both as a stand-alone system, and as coupled to magnetic resonance imaging and computed tomography imaging. Tracer kinetic modeling is also being developed to allow quantitative imaging of molecular binding in vivo.

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• Near-infrared imaging

  Near-infrared imaging

  Near-infrared imaging (NIR) provides a way to quantify blood and water concentrations in tissue, as well as structural and functional parameters. Since normal tissue, benign tumors, and malignant tumors each carry different concentrations of both hemoglobin and water, and have different levels of oxygen demand and ultrastructural scattering, NIR spectroscopy can be combined into standard imaging systems as an effective method of to provide additional information for breast cancer detection and diagnosis. Work is ongoing to improve techniques for better image reconstruction, display and integration with magnetic resonance imaging (MRI) and computed tomography (CT) imaging.

  See also Center for Imaging Medicine

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Selected Publications

• HA García, DA Vera, NA Carbone, MV Waks-Serra, JA Pomarico, "Analytical sensitivity factors from distributions of time of flight of photons for near-infrared spectroscopy studies in multilayered turbid media," J Biomed Opt, 2025, 30(1), 015002. DOI: https://doi.org/10.1117/1.JBO.30.1.015002
• MB Kulkarni, MS Reed, X Cao, HA García, MI Ochoa, S Jiang, T Hasan, MM Doyley, BW Pogue, "Combined dual-channel fluorescence depth sensing of indocyanine green and protoporphyrin IX kinetics in subcutaneous murine tumors," J Biomed Opt, 2024, 30(S1), S13709. DOI: https://doi.org/10.1117/1.JBO.30.S1.S13709
• DA Vera, HA García, NA Carbone, MV Waks Serra, DI Iriarte, JA Pomarico, "Retrieval of chromophore concentration changes in a digital human head model using analytical mean partial pathlengths of photons," J Biomed Opt, 2024, 29(2), 025004. DOI: https://doi.org/10.1117/1.JBO.29.2.025004
• NA Carbone, DA Vera, MV Waks Serra, HA García, DI Iriarte, JA Pomarico, PA Pardini, S Puca, N Fuentes, ME Renati, PH Capellino, R Osses, "MamoRef: an optical mammography device using whole-field CW diffuse reflectance. Presentation, validation and preliminary clinical results," Phys Med Biol, 2024, 69, 015021. DOI: https://doi.org/10.1088/1361-6560/ad1213
• DA Vera, HA García, MV Waks Serra, NA Carbone, DI Iriarte, JA Pomarico, "Determining light absorption changes in multilayered turbid media through analytically computed photon mean partial pathlengths," Opt P Apl, 2023, 56(2), 51145. DOI: http://dx.doi.org/10.7149/OPA.56.2.51145
• DA Vera, HA García, MV Waks Serra, GR Baez, DI Iriarte, JA Pomarico, "A Monte Carlo study of Near Infrared light propagation in the human head with lesions," Biomed Phys Eng Expr, 2022, 8(3), 035005. DOI: https://doi.org/10.1088/2057-1976/ac59f3
• HA García, DA Vera, MV Waks Serra, GR Baez, DI Iriarte, JA Pomarico, "Theoretical investigation of photon partial pathlengths in multilayered turbid media," Biomed Opt Expr, 2022, 13(4), 449514. DOI: https://doi.org/10.1364/BOE.449514
• DA Vera, GR Baez, HA García, DI Iriarte, JA Pomarico, "A comparison between plausible models in layered turbid media with geometrical variations applying a Bayesian selection criterion," Biomed Phys Eng Expr, 2020, 6(5), 055020. DOI: http://dx.doi.org/10.1088/2057-1976/abae48
• GR Baez, HA García, D Grosenick, H Wabnitz, "Implementation of the extended Kalman filter for determining the optical and geometrical properties of turbid layered media by time-resolved single distance measurements," Biomed Opt Expr, 2020, 11(1), 251–266. DOI: http://dx.doi.org/10.1364/BOE.11.000251
• HA García, GR Baez, JA Pomarico, "Simultaneous retrieval of optical and geometrical parameters of multilayered turbid media via state-estimation algorithms," Biomed Opt Expr, 2018, 9(8), 3953–3973. DOI: http://dx.doi.org/10.1364/BOE.9.003953
• HA García, DI Iriarte, JA Pomarico, D Grosenick, R Macdonald, "Retrieval of the optical properties of a semiinfinite compartment in a layered scattering medium by single-distance, time-resolved diffuse reflectance measurements," J Quant Spect Rad Trans, 2017, 189, 66–74. DOI: http://dx.doi.org/10.1016/j.jqsrt.2016.11.018