• Ph.D., Stanford University, 2007
  • M.S., Stanford University, 2004
  • B.S., Tsinghua University, Beijing, China, 2002

Research Areas and Descriptors

  • Medical Physics: X-ray imaging system development, algorithm design for tomographic reconstruction, imaging applications in radiation therapy, and advanced radiation therapy planning.


Dr. Zhu will come to Georgia Tech in August 2009. Before joining Georgia Tech, he worked in the Department of Radiology at Stanford University as a physical science research associate. His research interests were mainly focused on imaging technologies of advanced X-ray CT systems. He then transferred to the Department of Radiation Oncology, working on clinical applications of X-ray CT imaging and inverse treatment planning of radiation therapy.


Ever since the invention of X-ray computed tomography (CT), significant developments have been made in the direction of low-dose, fast imaging, and improved image quality. With new detector technologies, one natural outcome of this trend is increasing the size of the detector and using a cone beam X-ray source. X-ray cone beam CT (CBCT) gained heated attention in the past decade. Over the years, Dr. Zhu has performed research on advanced CBCT reconstruction algorithms, such as reconstruction using incomplete scan data, and artifacts reduction techniques, such as scatter correction for CBCT.

Besides imaging, X-rays are also routinely used for radiotherapy, which is now considered the most effective treatment method for many cancers. In the recent years, Dr. Zhu has worked on developing more accurate and efficient radiotherapy treatment planning algorithms. Using novel optimization techniques, such as compressed sensing and projection methods, he has developed effective dose delivery schemes for various radiotherapy modalities including fixed-gantry intensity modulation radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). Dr. Zhu's research has been supported by grants from the National Institute of Health (NIH) and the Department of Defense.

In addition to expansions of the previous research on X-ray CBCT imaging and radiotherapy planning, Dr. Zhu's current research is devoted to the synergy between these two fields. Specifically, he is interested in improving the quality of X-ray imaging in the image-guided radiotherapy (IGRT) and developing optimization schemes for adaptive radiation therapy.

Dr. Zhu's research covers the two main categories of medical physics: medical imaging and radiotherapy. Therefore, his program provides an ideal learning environment for the perspective students in almost all the aspects of medical physics. Students may develop their M.S. or Ph.D. research over a wide range of topics in engineering, physics and mathematics. They can work on physics or hardware related topics which may lead to an improved modality of imaging or therapy. They can also work on various inverse and optimization problems which may reformulate the conventional mathematical frameworks of image reconstruction and treatment planning.

After graduation, Dr. Zhu's graduate students may find a position in companies with research on medical physics. They can also take a career track of medical physicists in an academic institute or a clinic, which usually requires post-graduate clinical training.


  • The Radiological Society of North America Trainee Research Prize for "A new scatter correction method for x-ray CT using primary modulation," 2005
  • Stanford University Department of Electrical Engineering Fellowship Award, 2002
  • Tsinghua University (Beijing, China) "Best Bachelor Graduate" Honor, 2002


  • Scatter Correction for X-Ray Imaging Using Modulation of Primary X-Ray Spatial Spectrum (with Rebecca Fahrig), U.S. Patent 7,463,712 B2, December 9, 2008
  • Tomographic Reconstruction for X-Ray Cone-Beam Scan Data (with Rebecca Fahrig), U.S. Patent 7,409,033 B2, August 5, 2008
  • High Resolution 3D Gauss Meter (with Ning Wu), P.R.China Patent ZL 02 2 37537.6, August 13, 2003

Representative Publications

  • Lei Zhu, Jing Wang, and Lei Xing.  2009. Noise Suppression in Scatter Correction for Cone-Beam CT. Medical Physics 36(3), 741-752.

    Lei Zhu, et al. 2008. Using Total-Variation Regularization for Intensity Modulated Radiation Therapy Inverse Planning with Field-Specific Numbers of Segments. Physics and Medical Biology 53(23), 653–6672.

    Lei Zhu, Jared Starman, and Rebecca Fahrig. 2008. An Efficient Estimation Method for Reducing the Axial Intensity Drop in Circular Cone-Beam CT. International Journal of Biomedical Imaging 242841.

    Lei Zhu, Sungwon Yoon, and Rebecca Fahrig. 2007. A Short-Scan Reconstruction for Cone-Beam CT using Shift-Invariant FBP and Equal Weighting. Medical Physics 34(11), 4422–4438.

    Lei Zhu, N. Robert Bennett, and Rebecca Fahrig. 2006.  Scatter Correction Method for X-Ray CT using Primary Modulation: Theory and Preliminary Results. IEEE Transactions on Medical Imaging 25(12), 1573–1587.