Biomedical Imaging and Spectroscopy; Clinical Instrument Translation (BISCIT)

Photo of the research group BISCIT.

Our research focus is to develop methods and instrumentation that advance spectroscopy, light transport modeling, and imaging of tissue; creating quantitative, non-invasive tools for the clinical detection, monitoring or treatment of skin diseases and injuries.

Core Imaging Methods and Technologies

The imaging systems and methodologies developed in this group all are based on one fundamental optical technique for characterizing and quantifying optical parameters from highly scattering media like tissue: Spatial Frequency Domain Imaging/Spectroscopy (SFDI/S).  This is a relatively new technique that has several appealing attributes as a general measurement platform: low cost, quantitative in optical contrast, depth selective and spatially scalable. This technique measures the differentiated response of remitted light from tissue, when patterns (sinusoidal intensity projections of varying spatial frequency) are projected on to it. This approach quantifies the effective Modulation TransferFunction (MTF) of a diffuse optical system (in this case: tissue) and relates this function in terms of contributions from absorption and scattering.

Our lab advances spectroscopic methods in a way that exploits the molecular sensitivity, quantitation and non-invasiveness of SFDI/S, but extends the spatial resolution and depth selectivity through the use of recent advances in imaging technology (e.g. snap-shot hyperspectral imagers) and compressive sensing (e.g. single pixel imagers), as well as novel computational methods and models of light transport in order to translate these technologies into clinical settings. 

(Left): Clinical photo of biopsied skin, 2 weeks post; (middle): the determined absorption coefficient at 630nm which is related to hemoglobin concentrations, melanin, water, lipid, carotenoids; (right): the reduced scattering coefficient at 630nm, related to subcellular objects and collagen structures 

Clinical Applications and Deployment

The primary thrust of our research is focused on applications and collaborations that seek to address unmet needs in either primarily dermatological or models of disease in pre-clinical (small animal) settings: 

  • In terms of diagnostics, this measurement platform presents the opportunity to isolate (in space and depth) physiological and functional properties that directly relates to the biological processes present in disease or cancer.  We seek to develop non-invasive imaging tools with increased sensitivity and specificity to biological processes, thereby developing new, quantitative platform to study disease rather than just differentiating it. 
  • In terms of advancing light based therapies, this platform has the opportunity to characterize the optical properties present within affected tissue and therefore inform energy distribution of the light dose, as well as the therapeutic response. Light based treatment methods provide an exciting alternative to current cancer treatment methods as they could be (1) highly targeted, resulting in minimal collateral damage to healthy tissue, as well as (2) non- (or minimally) invasive, mitigating risks associated with surgical procedures. These methods, however, have yet to gain clinical acceptance due to a lack of quantitative imaging and evaluation tools. Two classes of therapies of particular interest are Photothermal Therapy (PTT) and Photodynamic Therapy (PDT).
  • Lastly, this platform has the opportunity to monitor structural changes in tissue in response to intervention, therapy and wound healing. Preliminary data indicate that all phases of the wound healing response (i.e. Hemostasis, Inflammation, Proliferation/ Granulation, and Tissue Remodeling/Maturation) and can be non-invasively identified and monitored longitudinally by the quantitative optical methods and models available in our lab. This platform not only allows for predictive therapeutic response, but also invites collaborations to study interventions that may promote and/or accelerate wound healing; thereby help expedite drug development in regenerative medicine. 

BISCIT Research Areas

External collaborations

  • The OpenSFDI initiative: is an online, open-source repository of tutorials, codes and step-by-step instructions on how to build spatial frequency domain instruments, how to process data and methods for testing, calibrating and validating these systems.Initiated by Darren Roblyer and Matthew Applegate (Boston University), this resource includes contributions from many other early adopters of this technique: Sylvain Gioux and Joseph Angelo (University of Strasbourg), Bruce Tromberg (NIH) and Anthony Durkin (UCI).

  • Compound-Eye, Multispectral Camera Design and Development: Keiichiro Kagawa, (Shizuoka University, Japan).Dr Kagawa and I have been collaborating on compact low-cost multispectral sensors that can be customized and optimized for biomedical imaging in clinical burn wound settings.

  • Development of structured phantoms to evaluate optical medical devices across diverse ethnic and clinical populations: T. Joshua Pfefer (FDA), Anthony J Durkin (UCI).This is an ongoing collaboration with the critical goal of developing traceable standards that can emulate real sources of optical contrast in a rigorously characterized manner. This project evaluates optics device and technology performance across such normal clinical variances as skin pigmentation, age, etc.

  • Precise Advanced Technologies and Health Systems for Underserved Populations (PATHS-UP): this is a multi-center initiative that includes Texas A&M, UCLA, Florida International University (FIU) and Rice University. Their mission is to engineer transformative, robust, and affordable, technologies and systems to improve healthcare access, enhance the quality of service and life, and reduce the cost of healthcare in underserved populations. Our group has been collaborating with Jessica Ramella-Roman (FIU) where we are contributing quantitative spectral data and light transport models for transcutaneous monitoring of obesity. This effort will inform the development of low-cost wearable devices at FIU to serve this population.

Latest publications


Hady Shahin, Luigi Belcastro, Jyotirmoy Das, Marina Perdiki Grigoriadi, Rolf Saager, Ingrid Steinvall, Folke Sjöberg, Pia Olofsson, Moustafa Elmasry, Ahmed Elserafy (2024) MicroRNA-155 mediates multiple gene regulations pertinent to the role of human adipose-derived mesenchymal stem cells in skin regeneration Frontiers in Bioengineering and Biotechnology, Vol. 12, Article 1328504 Continue to DOI


Hanna Jonsson, Joakim Henricson, Rolf Saager, Daniel Wilhelms (2023) Microcirculatory response to lower body negative pressure and the association to large vessel function PHOTONICS IN DERMATOLOGY AND PLASTIC SURGERY 2023, Article 123520A Continue to DOI
Johannes Johansson, Rolf Saager (2023) Development of a novel line scanner for speckle contrast diffuse correlation tomography of microvascular blood flow OPTICAL DIAGNOSTICS AND SENSING XXIII, Article 123870A Continue to DOI
Luigi Belcastro, Hanna Jonasson, Tomas Strömberg, Ahmed Elserafy, Rolf Saager (2023) Beneath the skin: multi-frequency SFDI to detect thin layers of skin using light scattering PHOTONICS IN DERMATOLOGY AND PLASTIC SURGERY 2023, Article 1235209 Continue to DOI


Motasam Majedy, Nandan K. Das, Johannes Johansson, Rolf B. Saager (2022) Influence of optical aberrations on depth-specific spatial frequency domain techniques Journal of Biomedical Optics, Vol. 27 Continue to DOI
Ali Afshari, Rolf B. Saager, David Burgos, William Vogt, Jianting Wang, Gonzalo Mendoza, Sandy Weininger, Kung-Bin Sung, Anthony Durkin, T. Joshua Pfefer (2022) Evaluation of the robustness of cerebral oximetry to variations in skin pigmentation using a tissue-simulating phantom Biomedical Optics Express, Vol. 13, p. 2909-2928 Continue to DOI
Hanna Jonasson, Chris D Anderson, Rolf B. Saager (2022) Water and hemoglobin modulated gelatin-based phantoms to spectrally mimic inflamed tissue in the validation of biomedical techniques and the modeling of microdialysis data Journal of Biomedical Optics, Vol. 27 Continue to DOI
Motasam Majedy, Rolf B. Saager, Tomas Strömberg, Marcus Larsson, Göran E. Salerud (2022) Spectral characterization of liquid hemoglobin phantoms with varying oxygenation states Journal of Biomedical Optics, Vol. 27, Article 74708 Continue to DOI


Development and evaluation of cell-based therapies for skin wounds

Seminar at IMT, march 18, 2021.

Group members