My research interests are focused on developing affordable biomedical optical imaging systems. My long term objectives aim to develop optical technologies for early diagnosis using molecular markers and treatment of atherosclerotic plaque. My multidisciplinary research experience and background in optical imaging positions me to develop new optical imaging technologies for potential deployment at an affordable cost. Optical imaging offers many exciting opportunities to develop minimally invasive, low-cost solutions for the detection and treatment of diverse diseases in cardiovascular and many other areas that are yet to be explored.

Academic Appointments

Honors & Awards

  • Travel Grant Award, World Molecular Imaging Congress (2015)
  • Selected as an Associate of the AAPM Science Council Associates Mentorship Program, American Association of Physicists in Medicine (2015-2016)
  • AAPM Young Investigator Award Finalist of SF Chapter, UC Berkeley, American Association of Physicists in Medicine (2015)
  • Guest Researcher at Annual Research Roundtable, American Heart Association (2015)
  • NIH Pathway to Independence Award (Parent K99/R00: priority score outstanding-excellent, National Institute of Health-National Heart, Lung, and Blood Institute (04/01/15-03/31/20)
  • Postdoctoral Fellow Travel Award, Stanford Cardiovascular Institute (2014)
  • “Best-in-Physics” Research Award to reflect the highest level of scientific quality and innovation, American Association of Physicists in Medicine (2014)
  • Guest Researcher at Annual Research Roundtable, American Heart Association (2014)
  • Biographical publication, Who’s Who in America (2014)
  • Postdoctoral Fellow Travel Award, Stanford Cardiovascular Institute (2013)
  • Melvin Judkins Young Investigator Award Finalist, American Heart Association Cardiovascular Radiology and Stroke Intervention Council (2013)
  • Top Abstract Award, featured at the Highlight Lecture during the Closing Ceremony, World Molecular Imaging Congress (2013)
  • Travel Grant Award, World Molecular Imaging Congress (2013)
  • Western State Affiliated Winter 2013 Postdoctoral Fellowship to conduct independent research, American Heart Association (2013)
  • Travel Grant Award, Engineering Conferences International Conference (2013)
  • Biographical publication, Who’s Who in America (2013)
  • Biographical publication, Who’s Who in Medicine and Healthcare (2012)
  • Top Abstract Award, featured at the Cardiovascular Highlight Session, Society of Nuclear Medicine Annual Meeting (2012)
  • Cardiovascular Imaging Scholar (CVIS), NIH T32 Training Grant, Stanford University School of Medicine (2011)
  • NIH T32 Training Grant, Radiation Biology Division, Stanford University School of Medicine (2011)
  • Biographical publication, Who’s Who in America (2011)
  • Outstanding Graduate Student Award, University of Texas at Austin (2011)
  • Travel Grant Award, American Society for Laser Medicine and Surgery (2011)
  • Travel Grant Award for an outstanding research paper, United State Air Force (2010)
  • Travel Grant Award, American Society for Laser Medicine and Surgery (2009)
  • Newport/Spectra Physics Research Excellent Award for original/outstanding research paper, International Society for Optics and Photonics (SPIE) (2009)
  • Professional Development Awards (2 times) for original/outstanding paper, University of Texas at Austin (2008-2009)
  • Travel Grant Award for an outstanding research paper, United State Air Force (2008)
  • Travel Grant Award from the Graduate Council, University of Texas at Austin (2007)
  • The Chancellor’s List Awards (2 times), University of Texas at Austin (2005-2006)
  • The National Dean’s List Awards (6 times), University of Texas at Austin (1995-2006)
  • Kudos award for “above and beyond performance”, Motorola Inc. Management (2003)
  • College Scholar, University of Texas at Austin (1999)
  • Electrical and Computer Engineering Academic Competitive Scholarship, University of Texas at Austin (1996-97)
  • Dean’s Honor List, Saint Mary’s University at San Antonio, TX (1995-96)
  • President Scholarship, St. Mary's University at San Antonio, TX (1995-96)
  • Richter scholarship, St. Mary's University at San Antonio, TX (1995-96)

Boards, Advisory Committees, Professional Organizations

  • Junior Member, American Association of Physicists in Medicine (2014 - Present)
  • Member, American Heart Association (2013 - Present)
  • Member, American Nano Society (2011 - Present)
  • Life time member, Magna Cum Laude National Scholars Honors Society (2008 - Present)
  • Member, American Society for Laser, Medicine, and Surgery (2007 - Present)
  • Member, International Society for Optics and Photonics (2007 - Present)
  • Member, International Society for Optical Engineering (2007 - Present)
  • Member, Optical Society of America (2007 - Present)
  • Life time member, International Scholar Laureate Program Delegation in Engineering (2006 - Present)
  • Member, Society of Women Engineers (2005 - Present)
  • Member, National Society of Professional Engineers (2005 - Present)
  • Member, Science Undergraduate Research Group(SURGe) (2000 - Present)
  • Life time member, National Society of Collegiate Scholars (1999 - Present)
  • Life time member, Golden Key National Honor Society (1999 - Present)

Professional Education

  • Post-doc, Stanford University School of Medicine, CA, Development of novel optical imaging system and image processing in Cardiology (2011)
  • Ph.D., University of Texas, Austin, TX, Biomedical Engineering (2011)
  • MSEE, University of Texas, Austin, TX, Electrical Engineering (2006)
  • BSEE, University of Texas, Austin, TX, Electrical and Computer Engineering (2000)


  • Raiyan Zaman,Henry G. Rylander, Ashley J. Welch. "United States Patent 61/239,341 Application of Hyper- osmotic Agent in Drug Delivery", University of Texas at Austin, Sep 2, 2009
  • Raiyan Zaman, James W. Tunnell. "United States Patent 12/139, 620 Measuring Nanoparticle Concentrations in Tissue using Diffuse Optical Spectroscopy", University of Texas at Austin, Dec 1, 2008

Research & Scholarship

Current Research and Scholarly Interests

My academic and scientific training has been focused on design and development of novel fiber-optic based biomedical instrumentation to improve the detection and, intervention, and treatment of various diseases. Currently, I am on a Western State Affiliate Winter 2013 Postdoctoral Fellowship from the American Heart Association (AHA) at the Stanford University School of Medicine in the laboratory of Professors Lei Xing and Michael V. McConnell, where I developed a novel fiber-optic catheter based optical imaging system to detect vulnerable atherosclerotic plaque in carotid arteries. In this work, I developed a novel scintillating balloon which can detect the vulnerable atherosclerotic plaque from stable plaque with high sensitivity after 18F-FDG uptake by the macrophages within the thin cap fibro atheroma (TCFA). The TCFA causes 60-70% of acute coronary syndrome that leads to sudden cardiac death and myocardial infarction.


Graduate and Fellowship Programs


All Publications

  • SU-D-201-03: Imaging Cellular Pharmacokinetics of 18F-FDG in Inflammatory/Stem Cells. Medical physics Zaman, R., Tuerkcan, S., Mahmoudi, M., TOSHINOBU, T., Kosuge, H., Yang, P., Chin, F., McConnell, M., Xing, L. 2015; 42 (6): 3220-?


    Atherosclerosis is a progressive inflammatory condition that underlies coronary artery disease (CAD)-the leading cause of death in the USA. Thus, understating the metabolism of inflammatory cells can be a valuable tool for investigating CAD. To the best of our knowledge, we are the first to successfully investigate the pharmacokinetics of [18F]fluoro-deoxyglucose (18F-FDG) uptake in a single macrophages and compared with induced pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs) with a novel imaging technique, radioluminescence microscopy, initially developed for cancer imaging.Live cells were cultured sparsely on Matrigel in a glass-bottom dish and starved for 1 hour before incubation with 250 microCi of 18F-FDG for 45 minutes. Excess radiotracer was removed using DMEM medium without glucose. Before imaging, DMEM (1 mL) was added to the cell culture and a 100 microm-thin CdWO4 scintillator plate was placed on top of the cells. Light produced following beta decay was imaged with a highly sensitive inverted microscope (LV200, Olympus) fitted with a 40x/1.3 high-NA oil objective, and an EM-CCD camera. The images were collected over 18,000 frames with 4×4 binning (1200 MHz EM Gain, 300ms exposure). Custom-written software was developed in MATLAB for image processing (Figure 1). For statistical analysis 10 different region-of-interests (ROIs) were selected for each cell type.Figures 2A-2B show bright-field/fusion images for all three different cell types. The relationship between cell-to-cell comparisons was found to be linear for macrophages unlike iPSCs and MSCs, which were best fitted with moving or rolling average (Figure 2C). The average observed decay of 18F-FDG in a single cell of MSCs per second (0.067) was 20% and 36% higher compared to iPSCs (0.054) and macrophages (0.043), respectively (Figure 2D).MSCs was found to be 2-3x more sensitive to glucose molecule despite constant parameters for each cell type examined.

    View details for DOI 10.1118/1.4923911

    View details for PubMedID 26127218

  • Scintillating balloon-enabled fiber-optic system for radionuclide imaging of atherosclerotic plaques. Journal of nuclear medicine Zaman, R. T., Kosuge, H., Carpenter, C., Sun, C., McConnell, M. V., Xing, L. 2015; 56 (5): 771-777


    Atherosclerosis underlies coronary artery disease, the leading cause of death in the United States and worldwide. Detection of coronary plaque inflammation remains challenging. In this study, we developed a scintillating balloon-enabled fiber-optic radionuclide imaging (SBRI) system to improve the sensitivity and resolution of plaque imaging using (18)F-FDG, a marker of vascular inflammation, and tested it in a murine model.The fiber-optic system uses a Complementary Metal-Oxide Silicon (CMOS) camera with a distal ferrule terminated with a wide-angle lens. The novelty of this system is a scintillating balloon in the front of the wide-angle lens to image light from the decay of (18)F-FDG emission signal. To identify the optimal scintillating materials with respect to resolution, we calculated the modulation transfer function of yttrium-aluminum-garnet doped with cerium, anthracene, and calcium fluoride doped with europium (CaF2:Eu) phosphors using an edge pattern and a thin-line optical phantom. The scintillating balloon was then fabricated from 10 mL of silicone RTV catalyst mixed with 1 mL of base and 50 mg of CaF2:Eu per mL. The addition of a lutetium oxyorthosilicate scintillating crystal (500 μm thick) to the balloon was also investigated. The SBRI system was tested in a murine atherosclerosis model: carotid-ligated mice (n = 5) were injected with (18)F-FDG, followed by ex vivo imaging of the macrophage-rich carotid plaques and nonligated controls. Confirmatory imaging of carotid plaques and controls was also performed by an external optical imaging system and autoradiography.Analyses of the different phosphors showed that CaF2:Eu enabled the best resolution of 1.2 μm. The SBRI system detected almost a 4-fold-higher radioluminescence signal from the ligated left carotid artery than the nonligated right carotid: 1.63 × 10(2) ± 4.01 × 10(1) vs. 4.21 × 10(1) ± 2.09 × 10(0) (photon counts), P = 0.006. We found no significant benefit to adding a scintillating crystal to the balloon: 1.65 × 10(2) ± 4.07 × 10(1) vs. 4.44 × 10(1) ± 2.17 × 10(0) (photon counts), P = 0.005. Both external optical imaging and autoradiography confirmed the high signal from the (18)F-FDG in carotid plaques versus controls.This SBRI system provides high-resolution and sensitive detection of (18)F-FDG uptake by murine atherosclerotic plaques.

    View details for DOI 10.2967/jnumed.114.153239

    View details for PubMedID 25858046

  • Fiber-Optic System for Dual-Modality Imaging of Glucose Probes F-18-FDG and 6-NBDG in Atherosclerotic Plaques PLOS ONE Zaman, R. T., Kosuge, H., Pratx, G., Carpenter, C., Xing, L., McConnell, M. V. 2014; 9 (9)
  • Fiber-Optic System for Dual-Modality Imaging of Glucose Probes 18F-FDG and 6-NBDG in Atherosclerotic Plaques PloS One Zaman, R. T., Kosuge, H., Pratx, G., Carpenter, C., Xing, L., McConnell, M. V. 2014
  • Micro-patterned drug delivery device for light-activated drug release LASERS IN SURGERY AND MEDICINE Zaman, R. T., Gopal, A., Starr, K., Zhang, X., Thomsen, S., Tunnell, J. W., Welch, A. J., Rylander, H. G. 2012; 44 (1): 30-48


    The primary goal of this study was the fabrication, long-term stability, and measured release of a marker dye from a micro-patterned drug delivery device using (i) mechanical puncture and (ii) photodisruption with an ophthalmic Nd:YAG laser.A drug delivery device was made from a transparent bio-compatible polymer. The device consisted of two 2.6?mm diameter reservoirs containing 10% Na fluorescein dye. The device was implanted in the rabbit's eye (n?=?2) with the cap of the device facing toward the exterior of the eye. Once the animals recovered from the implant surgery, 100% anhydrous glycerol was topically applied to the eye at the implantation site to decrease light scattering in the conjunctiva and sclera. The dye was released from one of the reservoir either using a 28?G ½ needle or an ophthalmic Q-switched Nd:YAG laser. A fluorescence spectrophotometer (FS) with fiber optic probe was used to measure the half-life of the dye in the eye. Measurements of fluorescence intensity were collected until the measurements return to baseline and histology was done on the tissue surrounded the device.None of the devices leaked of 10% Na fluorescein dye after implant. The ablation threshold of the drug delivery device was between 6 and 10?mJ to create 100-500?µm holes. The half-life measurement of the dye was found to be 13 days at the vitreous chamber after measuring the fluorescence intensity through the dilated cornea. Histology study showed minimal immune and foreign body response such as mild inflammation.This study established that the drug delivery device seemed to elicit minimal inflammatory response and retained its fluidic content until it was released with relatively longer retention time (half-life). Thus, similar device could be used for controlled release of drugs for certain ocular diseases.

    View details for DOI 10.1002/lsm.21149

    View details for Web of Science ID 000299076500006

    View details for PubMedID 22127811

  • Changes in morphology and optical properties of sclera and choroidal layers due to hyperosmotic agent JOURNAL OF BIOMEDICAL OPTICS Zaman, R. T., Rajaram, N., Nichols, B. S., Rylander, H. G., Wang, T., Tunnell, J. W., Welch, A. J. 2011; 16 (7)


    Light scattering in the normally white sclera prevents diagnostic imaging or delivery of a focused laser beam to a target in the underlying choroid layer. In this study, we examine optical clearing of the sclera and changes in blood flow resulting from the application of glycerol to the sclera of rabbits. Recovery dynamics are monitored after the application of saline. The speed of clearing for injection delivery is compared to the direct application of glycerol through an incision in the conjunctiva. Although, the same volume of glycerol was applied, the sclera cleared much faster (5 to 10 s) with the topical application of glycerol compared to the injection method (3 min). In addition, the direct topical application of glycerol spreads over a larger area in the sclera than the latter method. A diffuse optical spectroscopy system provided spectral analysis of the remitted light every two minutes during clearing and rehydration. Comparison of measurements to those obtained from phantoms with various absorption and scattering properties provided estimates of the absorption coefficient and reduced scattering coefficient of rabbit eye tissue.

    View details for DOI 10.1117/1.3599985

    View details for Web of Science ID 000294453800046

    View details for PubMedID 21806288

  • Variation of Fluorescence in Tissue with Temperature LASERS IN SURGERY AND MEDICINE Zaman, R. T., Rajaram, N., Walsh, A., Oliver, J., Rylander, H. G., Tunnell, J. W., Welch, A. J., Mahadevan-Jansen, A. 2011; 43 (1): 36-42


    Previous studies demonstrated a decrease in fluorescence intensity as tissue temperature increased. In vitro samples were increased from room temperature and in vivo canine liver from body temperature. This study investigated variations in fluorescence intensity with temperatures starting at 14°C and compared in vivo and in vitro results for consistency.A fiber optic-based noninvasive system was used to characterize the temperature effect on tissue fluorescence in hamster dorsal skin in vivo, and in sclera and cornea of enucleated pig eyes in vitro. As tissue was allowed to progress through the temperature range of 14-42°C, the spectra of auto-fluorescence with respect to temperature was sampled every 1-2 minutes. A pulsed nitrogen laser was used to excite fluorescence through a fiber optic probe with a source-detector aperture separation of 370?µm.Fluorescence intensity decreased as temperature increased from 14 to 42°C in a phantom containing Rhodamine B dye. Results from both in vivo and in vitro tissue followed the same trend of decreasing intensity as tissue temperature increased from 14°C. Spectral intensity lineshape changed around 450?nm due to absorption from tissue.Cooling a tissue increased fluorescence intensity of skin in vivo, in all experiments. In vitro results were consistent with in vivo measurements.

    View details for DOI 10.1002/lsm.21023

    View details for Web of Science ID 000286440300006

    View details for PubMedID 21254141

  • Perfusion in Hamster Skin Treated With Glycerol LASERS IN SURGERY AND MEDICINE Zaman, R. T., Parthasarathy, A. B., Vargas, G., Chen, B., Dunn, A. K., Rylander, H. G., Welch, A. J. 2009; 41 (7): 492-503


    The objective of this article is to quantify the effect of hyper-osmotic agent (glycerol) on blood velocity in hamster skin blood vessels measured with a dynamic imaging technique, laser speckle contrast imaging (LSCI).In this study a dorsal skin-flap window was implanted on the hamster skin. The hyper-osmotic drug, that is, glycerol was delivered to the skin through the open dermal end of the window model. A two-dimensional map of blood flow of skin blood vessels was obtained from the speckle contrast (SC) images.Preliminary studies demonstrated that hyper-osmotic agents such as glycerol not only make tissue temporarily transparent, but also reduce blood flow. The blood perfusion was measured every 3 minutes for 36-66 minutes after diffusion of anhydrous glycerol. Blood flow in small capillaries was found to be reduced significantly within 3-9 minutes. Blood flow in larger blood vessels (i.e., all arteries and veins) decreased over time and some veins had significantly reduced blood flow within 36 minutes. At 24 hours, there was a further reduction in capillary blood perfusion whereas larger blood vessels regained flow compared to an hour after initial application of glycerol.Blood flow velocity and vessel diameter of the micro-vasculatures of hamster skin were reduced by the application of 100% anhydrous glycerol. At 24 hours, capillary perfusion remained depressed.

    View details for DOI 10.1002/lsm.20803

    View details for Web of Science ID 000269710800004

    View details for PubMedID 19670326

  • In Vivo Detection of Gold Nanoshells in Tumors Using Diffuse Optical Spectroscopy IEEE Journal of Selected Topics in Quantum Electronics Raiyan T. Zaman, Parmeswaran Diagaradjane, James Wong, Jon Schwartz, Narasimhan Rajaram, Henry G. Rylander III, Sunil Krishnan, James W. Tunnell 2007; 13 (6): 1715?1720

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