Intra-fractional organ motion is a predominant limiting factor for the maximum exploitation of modern prostate intensity modulated radiation therapy (IMRT) or volumetric modulated radiation therapy (VMAT). Adverse influence of the organ motion is further aggravated in hypofractionated treatment because of protracted dose delivery. In this project we will develop a real-time fiducial tracking strategy using a combined MV and kV imaging to solve the problem of intra-fraction prostate movement. The underlying hypothesis of this work is that real-time image guided prostate radiation therapy will greatly reduce the uncertainty in beam targeting and provide substantially improved dose distributions required to achieve greater local tumor control while reducing the probability of normal tissue complications.
Specific aims of the project are to (1) Refine a hybrid MV/kV image acquisition protocol for IMRT and VMAT;(2) Evaluate the potential clinical impact of the hybrid image guidance technique through a pilot clinical study. Successful completion of this investigation will provide radiation oncology discipline a critically needed means to treat prostate cancer, and afford a powerful way for us to safely and reliably escalate the radiation dose using IMRT/VMAT. Given its significant promise to optimally cater for intra-fractional uncertainties, successful completion of the project should lead to substantial improvement in prostate cancer patient care.

Public Health Relevance

In current prostate intensity modulated radiation therapy (IMRT) or volumetric modulated radiation therapy (VMAT), the adverse effect of intra-fractional prostate motion is compensated by introducing a large PTV margin, which leads to irradiation of adjacent critical organs and limits the prostate dose escalation. With the goal of rapidly deploying a previously developed kV/MV real-time tumor tracking technique into routine clinical practice, in this R21 application we plan to conduct a series of evaluations of the efficacy and clinical potential of the real-time image guidance strategy for prostate radiation therapy. Successful completion of this investigation will provide a critically needed means for treating prostate cancer and afford a powerful way for us to safely and reliably escalate radiation dose using IMRT.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Exploratory/Developmental Grants (R21)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-SBIB-V (51))
Program Officer
Deye, James
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Stanford University
Schools of Medicine
United States
Zip Code
Azcona, Juan Diego; Barb├ęs, Benigno; Wang, Lilie et al. (2016) Experimental pencil beam kernels derivation for 3D dose calculation in flattening filter free modulated fields. Phys Med Biol 61:50-66
Li, Ruijiang; Xing, Lei; Horst, Kathleen C et al. (2014) Nonisocentric treatment strategy for breast radiation therapy: a proof of concept study. Int J Radiat Oncol Biol Phys 88:920-6
Azcona, Juan Diego; Xing, Lei; Chen, Xin et al. (2014) Assessing the dosimetric impact of real-time prostate motion during volumetric modulated arc therapy. Int J Radiat Oncol Biol Phys 88:1167-74
Bazalova, Magdalena; Ahmad, Moiz; Pratx, Guillem et al. (2014) L-shell x-ray fluorescence computed tomography (XFCT) imaging of Cisplatin. Phys Med Biol 59:219-32
Fahimian, Benjamin; Wu, Junqing; Wu, Huanmei et al. (2014) Dual-Gated Volumetric Modulated Arc Therapy. Radiat Oncol 9:209
Meng, Bowen; Xing, Lei; Han, Bin et al. (2013) Cone beam CT imaging with limited angle of projections and prior knowledge for volumetric verification of non-coplanar beam radiation therapy: a proof of concept study. Phys Med Biol 58:7777-89
Xiang, Liangzhong; Han, Bin; Carpenter, Colin et al. (2013) X-ray acoustic computed tomography with pulsed x-ray beam from a medical linear accelerator. Med Phys 40:010701
Kuang, Yu; Pratx, Guillem; Bazalova, Magdalena et al. (2013) First demonstration of multiplexed X-ray fluorescence computed tomography (XFCT) imaging. IEEE Trans Med Imaging 32:262-7
Azcona, Juan Diego; Li, Ruijiang; Mok, Edward et al. (2013) Automatic prostate tracking and motion assessment in volumetric modulated arc therapy with an electronic portal imaging device. Int J Radiat Oncol Biol Phys 86:762-8
Li, Ruijiang; Xing, Lei (2013) An adaptive planning strategy for station parameter optimized radiation therapy (SPORT): Segmentally boosted VMAT. Med Phys 40:050701

Showing the most recent 10 out of 24 publications