Woodruff School of Mechanical Engineering

NRE/MP Seminar

Nuclear & Radiological Engineering and Medical Physics Programs


Toward Adaptive Radiation Therapy


Dr. Lei Zhu


GA Institute of Technology, Medical Physics


Thursday, September 17, 2009 at 11:00:00 AM


MRDC Building, Room 2404


Bojan Petrovic


The current intensity-modulated or image-guided radiation therapy (IMRT, IGRT) uses fractionation based on planning images. To compensate for the dose delivery error due to the patient deformation in each fraction, adaptive radiation therapy is becoming increasingly important for the overall treatment performance. This talk addresses the challenges toward the clinical practice of adaptive radiation therapy. Specifically, the first part of the presentation focuses on the improvement of CT imaging accuracy on the treatment machines for the calculation of 'dose of the day'. Main artifacts in the current cone-beam CT images are identified and promising solutions are presented. Inverse treatment re-planning schemes for the known previous dose delivery is then discussed. In the treatment planning optimization, a mathematically 'sparse' solution results in a small number of beam segments and therefore is preferred for a high efficiency of dose delivery. To achieve such a treatment plan, a novel framework of treatment planning is proposed using compressed sensing techniques. Implementations of this framework in the current IMRT applications are shown. The talk finally discusses the future work for the eventual clinical implementation of adaptive radiation therapy.


Dr. Lei Zhu graduated with highest honors from the Department of Electrical Engineering, Tsinghua University (Beijing, China), with a B.S. Degree in 2002. He then received M.S. and Ph.D. Degrees both in Electrical Engineering from Stanford University, in 2004 and 2007. His Ph.D. study was focused on advanced x-ray CT imaging systems. After graduation, he worked as a physical science research associate in the Department of Radiation Oncology, the School of Medicine at Stanford University. Research topics included the clinical applications of x-ray CT imaging and inverse treatment planning of radiation therapy. In 2009, Dr. Zhu joined Georgia Tech as an assistant professor in the Nuclear and Radiological Engineering and Medical Physics Programs, George W. Woodruff School of Mechanical Engineering. In addition to expansions of the previous research, his current research interests include imaging system development in the applications of image-guided therapy, adaptive radiation therapy and biology-guided radiation therapy. He has received several research awards, including a Trainee Research Prize from the Radiological Society of North America (RSNA).


Refreshments will be served.