Ehsan Samei, Professor of Radiology and Physics and Member of Duke Cancer Institute  

Ehsan Samei

Office Location: 2424 Erwin Road, Suite 302, Ravin Advanced Imaging Labs, Durham, NC 27705
Email Address:
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Biological physics

Ph.D., University of Michigan at Ann Arbor, 1997
M.E., University of Michigan at Ann Arbor, 1995

Research Categories: Medical Physics

Research Description: Dr. Samei’s research interests include theoretical and experimental methods in medical image formation, analysis, display, and perception, with particular emphasis on factors, methods, and procedures that impede and improve the radiological detection and diagnosis of early cancer. More specifically, his research in recent years has focused on the four areas discussed below. 1. Correlation and stereo imaging for improved early detection of cancer The early detection of lung cancer has been one of the outstanding challenges in radiographic imaging, the significance of which can be discerned only by considering the fact that lung cancer remains the leading cause of cancer death in the US, surpassing breast, prostate, colon, and cervical cancers combined. His prior research has shown that interference of the anatomical structure is the dominant factor in the low detection of early lung cancer in radiographic images. Grounded on this basic understanding, Correlation Imaging (CI) aims to develop a more sensitive image acquisition and processing approach that minimizes this influence, and therefore improves the early detection of lung cancer. The NIH awarded Dr. Samei R21 and R01 grants to study the feasibility of this imaging approach. With that funding, chest correlation and stereo imaging was developed from an initial design into a state-of-the-art prototype imaging system (fully developed and integrated at Duke). The prototype equipment is now being used in a clinical trial to assess the clinical utility of this novel imaging technique. As of now, more than 80 patients have been imaged, and the preliminary findings are very encouraging. Furthermore, Dr. Samei significantly contributed to and served as a key investigator on an R01 grant aimed to develop a cone beam CT imaging system (PI: Martin Tornai, PhD) and tomosynthesis (PI: Joseph Lo, PhD) for breast imaging at Duke. Dr. Samei has an active interest in developing other advanced x-ray imaging techniques for the early detection of cancer including limited angle and inverse geometry CT. 2. Objective assessment and impact of display quality on diagnostic accuracy The way in which medical image data are displayed has a direct influence on diagnosis. This dependency is task-specific, and for many tasks in medical imaging, including the early detection and classification of cancer, has not been fully substantiated in quantitative terms. For the last few years, Dr. Samei has led a national task force (AAPM TG18), and served on an ACR and an IEC committee to define standard testing methodologies for medical display devices. His research in this area is currently focused on the influence of display characteristics on the diagnostic interpretation of breast cancer and lung cancer, the fine-tuning of new testing methodologies, and on the influence of ambient light in diagnostic accuracy. These studies are funded by the NIH and the display industry. 3. Objective assessment and clinical relevance of image quality While image quality is a common term in radiology circles, its quantification has proven to be complex, as many factors contribute to the overall degradation of a medical image. Dr. Samei’s research and prior publications have provided a framework for assessing the performance of digital radiography systems, as recently reflected in an international standard on image quality measurements (IEC 62220-1). He is currently pursuing methods to further streamline the assessment methodologies and include other important contributing yet hitherto ignored factors such as scattered radiation. Furthermore, the connection between diagnostic accuracy and the scientific metrics of image quality is not straightforward. Two studies are now in progress to substantiate the relevance of these quantities in radiography (chest and breast) and in computed tomography (pediatric CT). The former investigation, initiated in his laboratory, is supported by a pre-doctoral grant from the DOD. The pediatric CT research initiative, supported by a current industrial grant from GE, aims to investigate strategies to reduce radiation dose in pediatric CT without compromising diagnostic quality. 4. Quantitative imaging By and large, since its inception, radiology as a discipline has been developed as a qualitative discipline in which physicians “interpret” medical images to gain diagnostic insights. However, current, mostly digital, medical images contain a large amount of information, which if effectively harnessed, can be invaluable in the quantification of the disease, in the assessment of the effectiveness of various therapeutic regimens, and in providing tractability of the medical information toward evidenced-based and patient-specific medicine. The main technical obstacle preventing this potential has been the lack of certainty about the extent to which image data can be analyzed quantitatively in light of various sources of variability (eg, case variability, patient positioning, system variability, etc). However, there is little doubt that the future of radiology is quantitative, and additional research is warranted to lead to that transition. Dr. Samei has recently initiated a number of research projects aiming to assess the relative magnitude of the sources of variability in diagnostic radiology, and from that to devise approaches by which robust quantitative data can be extracted from medical images. Initial projects have focused on CT and breast tomosynthesis. Additional projects are planned for digital mammography and digital radiography. He is also fostering additional quantitative imaging projects led by other faculty members in RAI Labs. With the preliminary results of these ongoing initiatives, he aims to lead RAI Labs toward a comprehensive program project on quantitative imaging. 5.Molecular imaging X-ray imaging is now used extensively throughout the world due to its low cost, widespread availability, speed, ease of interpretation, and exquisite representation of anatomy. However, it has to date been limited to structural imaging. But, the underlying processes behind many human diseases occur at the molecular level, suggesting many advantages that the imaging of these molecular and functional processes can provide. In spite of the dominance, cost-effectiveness and maturity of x-ray imaging, almost all molecular imaging investigators have focused their research on non-x-ray based technologies such as MRI, nuclear medicine, and optical imaging techniques. Dr. Samei has recently initiated a few preliminary studies to assess how conventional x-ray imaging can be extended to provide molecular and functional information. The overall goal of his investigation is to develop x-ray-based molecular and functional imaging methods. While maintaining the key advantages of x-ray imaging, the proposed method will provide functional images that have higher spatial and temporal resolution than what is currently possible through more “conventional” functional imaging methods (eg, Nuclear Medicine and fMRI), and that are inherently co-registered to anatomical information. The method employs nano-particle, “smart,” liposomal contrast agents to reveal specific functional and molecular processes and physiological functions within the human body, initially for the purpose of early detection of cancer and cardiovascular disease, the two leading causes of death world-wide. The pursuit of this project is particularly timely in light of recent developments in the fabrication of stable nano-particle liposomes and the development of antibody labeling methods. The application of functional and molecular imaging to x-ray technology has the potential to profoundly impact global clinical practice by spreading the benefits of functional imaging through a more accessible technology, unleashing the power and the promise of molecular imaging for many.

Areas of Interest:
Medical Physics

Representative Publications   (More Publications)

  1. E Samei, E Buhr, P Granfors, D Vandenbroucke, X Wang, Comparison of edge analysis techniques for the determination of the MTF of digital radiographic systems., Physics in medicine and biology, vol. 50 no. 15 (August, 2005), pp. 3613-25 [doi]  [abs].
  2. NT Ranger, E Samei, JT Dobbins 3rd, CE Ravin, Measurement of the detective quantum efficiency in digital detectors consistent with the IEC 62220-1 standard: practical considerations regarding the choice of filter material., Medical physics, vol. 32 no. 7 (July, 2005), pp. 2305-11  [abs].
  3. E Samei, JY Lo, TT Yoshizumi, JL Jesneck, JT Dobbins 3rd, CE Floyd Jr, HP McAdams, CE Ravin, Comparative scatter and dose performance of slot-scan and full-field digital chest radiography systems., Radiology, vol. 235 no. 3 (June, 2005), pp. 940-9 [doi]  [abs].
  4. E Samei, A Badano, D Chakraborty, K Compton, C Cornelius, K Corrigan, MJ Flynn, B Hemminger, N Hangiandreou, J Johnson, DM Moxley-Stevens, W Pavlicek, H Roehrig, L Rutz, J Shepard, RA Uzenoff, J Wang, CE Willis, AAPM TG18, Assessment of display performance for medical imaging systems: executive summary of AAPM TG18 report., Medical physics, vol. 32 no. 4 (April, 2005), pp. 1205-25  [abs].
  5. RS Saunders Jr, E Samei, JL Jesneck, JY Lo, Physical characterization of a prototype selenium-based full field digital mammography detector., Medical physics, vol. 32 no. 2 (February, 2005), pp. 588-99  [abs].
  6. E Samei, JT Dobbins 3rd, JY Lo, MP Tornai, A framework for optimising the radiographic technique in digital X-ray imaging., Radiation protection dosimetry, vol. 114 no. 1-3 (2005), pp. 220-9 [doi]  [abs].
  7. E Samei, A Rowberg, E Avraham, C Cornelius, Toward clinically relevant standardization of image quality., Journal of digital imaging, vol. 17 no. 4 (December, 2004), pp. 271-8 [doi]  [abs].
  8. E Samei, SL Wright, Luminance and contrast performance of liquid crystal displays for mammographic applications., Technology in cancer research & treatment, vol. 3 no. 5 (October, 2004), pp. 429-36  [abs].
  9. U Neitzel, S Günther-Kohfahl, G Borasi, E Samei, Determination of the detective quantum efficiency of a digital x-ray detector: comparison of three evaluations using a common image data set., Medical physics, vol. 31 no. 8 (August, 2004), pp. 2205-11  [abs].
  10. H Jung, HJ Kim, WS Kang, SK Yoo, K Fujioka, M Hasegawa, E Samei, Assessment of flat panel LCD primary class display performance based on AAPM TG 18 acceptance protocol., Medical physics, vol. 31 no. 7 (July, 2004), pp. 2155-64  [abs].
  11. RS Saunders Jr, E Samei, C Hoeschen, Impact of resolution and noise characteristics of digital radiographic detectors on the detectability of lung nodules., Medical physics, vol. 31 no. 6 (June, 2004), pp. 1603-13  [abs].
  12. RL McKinley, MP Tornai, E Samei, ML Bradshaw, Simulation study of a quasi-monochromatic beam for x-ray computed mammotomography., Medical physics, vol. 31 no. 4 (April, 2004), pp. 800-13  [abs].
  13. E Samei, JA Seibert, K Andriole, A Badano, J Crawford, B Reiner, MJ Flynn, P Chang, AAPM/RSNA tutorial on equipment selection: PACS equipment overview: general guidelines for purchasing and acceptance testing of PACS equipment., Radiographics : a review publication of the Radiological Society of North America, Inc, vol. 24 no. 1 (July, 2004), pp. 313-34 [doi]  [abs].
  14. RS Saunders Jr, E Samei, A method for modifying the image quality parameters of digital radiographic images., Medical physics, vol. 30 no. 11 (November, 2003), pp. 3006-17  [abs].
  15. E Samei, Image quality in two phosphor-based flat panel digital radiographic detectors., Medical physics, vol. 30 no. 7 (July, 2003), pp. 1747-57  [abs].
  16. E Samei, MJ Flynn, E Peterson, WR Eyler, Subtle lung nodules: influence of local anatomic variations on detection., Radiology, vol. 228 no. 1 (July, 2003), pp. 76-84 [doi]  [abs].
  17. E Samei, MJ Flynn, An experimental comparison of detector performance for direct and indirect digital radiography systems., Medical physics, vol. 30 no. 4 (April, 2003), pp. 608-22  [abs].
  18. E Samei, JG Hill, GD Frey, WM Southgate, E Mah, D Delong, Evaluation of a flat panel digital radiographic system for low-dose portable imaging of neonates., Medical physics, vol. 30 no. 4 (April, 2003), pp. 601-7  [abs].
  19. E Samei, MJ Flynn, An experimental comparison of detector performance for computed radiography systems., Medical physics, vol. 29 no. 4 (April, 2002), pp. 447-59  [abs].
  20. E Samei, JA Seibert, CE Willis, MJ Flynn, E Mah, KL Junck, Performance evaluation of computed radiography systems., Medical physics, vol. 28 no. 3 (March, 2001), pp. 361-71  [abs].
  21. E Mah, E Samei, DJ Peck, Evaluation of a quality control phantom for digital chest radiography., Journal of applied clinical medical physics / American College of Medical Physics, vol. 2 no. 2 (2001), pp. 90-101 [doi]  [abs].
  22. KJ Kearfott, S Han, EC Wagner, E Samei, CK Wang, Numerical simulation of a TLD pulsed laser-heating scheme for determination of shallow dose and deep dose in low-LET radiation fields., Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine, vol. 52 no. 6 (June, 2000), pp. 1419-29  [abs].
  23. MJ Flynn, E Samei, Experimental comparison of noise and resolution for 2k and 4k storage phosphor radiography systems., Medical physics, vol. 26 no. 8 (August, 1999), pp. 1612-23  [abs].
  24. E Samei, MJ Flynn, DA Reimann, A method for measuring the presampled MTF of digital radiographic systems using an edge test device., Medical physics, vol. 25 no. 1 (January, 1998), pp. 102-13  [abs].
  25. GH Beute, MJ Flynn, WR Eyler, E Samei, DL Spizarny, CJ Zylak, Chest radiographic image quality: comparison of asymmetric screen-film, digital storage phosphor, and digital selenium drum systems--preliminary study., Radiographics : a review publication of the Radiological Society of North America, Inc, vol. 18 no. 3 (August, 1998), pp. 745-54  [abs].
  26. E Samei, MJ Flynn, WR Eyler, Simulation of subtle lung nodules in projection chest radiography., Radiology, vol. 202 no. 1 (January, 1997), pp. 117-24  [abs].
  27. KJ Kearfott, S Han, KL McMahan, E Samei, Sensitivity of a mixed field dosimetry algorithm to uncertainties in thermoluminescent element readings., Health physics, vol. 68 no. 3 (March, 1995), pp. 340-9  [abs].


Dr. Ehsan Samei, PhD, DABR, FAAPM, FSPIE is a tenured Professor of Radiology, Medical Physics, Biomedical Engineering, Physics, and Electrical and Computer Engineering at Duke University, where he also serves as the Director of Carl E. Ravin Advanced Imaging Laboratories and the founding Chief of the Clinical Imaging Physics Group. He is certified by the American Board of Radiology, and is a Fellow of the American Association of Physicists in Medicine (AAPM), and the International Society of Optical Engineering (SPIE). He was the founding Director of the Graduate Studies of the Duke Medical Physics Graduate Program, and the co-founder of the Society of Directors of Academic Medical Physics Programs (SDAMPP). He has held senior leadership positions in the AAPM, the SPIE, and SDAMPP. He is a Councilor of the National Council of Radiation Protection and Measurements (NCRP), and a Distinguished Investigator of the Academy of Radiology Research.

Dr. Samei’s interests and expertise include x-ray imaging, theoretical imaging models, simulation methods, and experimental techniques in medical image formation, analysis, assessment, display, and perception. His current research includes methods to develop image quality and dose metrics that are clinically relevant and that can be used to design and utilize advanced imaging techniques towards precise interpretive and quantitative performance. He further has an active interest in bridging the gap between scientific scholarship and clinical practice, in the meaningful realization of translational research and in clinical processes that are informed by scientific evidence. While he works across most diagnostic imaging modalities, his main modalities of interest are CT and Tomosynthesis for breast, lung, and abdominal imaging applications. He has been the recipient of 29 extramural grants from the US government, private foundations, and medical industry, and has 700 scientific publications including 190 referred journal articles.