Lei Ren, Devon Godfrey, Hui Yan, Jing Cai, Zheng Chang, Jackie Wu, Sua Yoo, James Bowsher, Fang-Fang Yin
IGRT has been widely applied in radiation therapy to use various imaging tools to improve the localization accuracy of the treatment. With the development of flat panel detectors, cone-beam CT (CBCT) has become a key imaging tool in IGRT, which is able to provide volumetric information about the patient for 3D or 4D target localization. MRI is another valuable tool under intensive study which is useful for target delineation and treatment assessment. Our group’s focus is to develop novel image acquisition and reconstruction techniques to improve the image quality and reduce imaging dose for various imaging modalities in IGRT.
Specifically we are focusing on the following directions:
- Imaging dose reduction using digital tomosynthesis (DTS). DTS only uses limited angle projections to reconstruct quasi-3D images; therefore it has much lower imaging dose than CBCT. This project is to evaluate the efficacy of DTS image guidance for different anatomic sites, including head-and-neck, prostate, breast, liver and lung.
- Development of clinical platform for DTS application. This project focuses on accelerating reconstruction using graphics card and developing user-friendly GUI interface for clinical use.
- Image reconstruction using prior knowledge and deformation models. A new method is developed to reconstruct full 3D images from limited-angle projections using patient prior knowledge and deformation models. Different deformation models, including PCA based motion models (MM) and free-form deformation (FD) model, are explored to improve the accuracy and efficiency.
- CBCT scatter correction. A synchronized moving grid (SMOG) system is being developed to correct for scatter, image lag and gantry flex of the flat panel detector based cone-beam CT (CBCT) system.
- Dual source CBCT. A dual source CBCT system has been built and its performance is being characterized. Virtual monochromatic (VM) and linearly mixed (LM) CBCTs are also developed to investigate their potential applications in metal artifact reduction and contrast enhancement in IGRT.
- Marker-less self-sorted 4D-CBCT. To develop an automatic projection sorting algorithm based on Fourier transformation of the projections.
- Fast reconstruction and processing of MR water-fat imaging, angiography, and quantitative functional imaging such as diffusion and perfusion imaging along with its clinical applications.
Varian Medical System
D. J. Godfrey, F. F. Yin, M. Oldham, S. Yoo, C. Willett, “Digital tomosynthesis using an on-board kV imaging device,” Int. J. Radiat. Oncol. Biol. Phys. 65(1), 8-15 (2006).
Q. J. Wu, D. J. Godfrey, Z. Wang, J. Zhang, S. Zhou, S. You, D. Brizel, F. Yin, ”On-board patient positioning for head and neck IMRT: comparing digital tomosynthesis to kV radiography and cone-beam CT.” Int. J. Radiat. Oncol. Biol. Phys. 69(2), 598-606 (2007).
D. J. Godfrey, L. Ren, H. Yan, Q. Wu, S. Yoo, M. Oldham, F. Yin, “Evaluation of three types of reference image data for external beam radiotherapy target localization using digital tomosynthesis (DTS).” Med. Phys. 34(8) 3374-3384 (2007).
H. Yan, L. Ren, D. J. Godfrey, F. Yin, “Accelerating reconstruction of reference digital tomosynthesis using graphics hardware.” Med. Phys. 34(10), 3768-3776 (2007).
L. Ren, D. J. Godfrey, H. Yan, Q. J. Wu, F. Yin, “Automatic registration between reference and on-board digital tomosynthesis images for positioning verification.” Med. Phys. 35, 664 (2008).
H. Yan, D. J. Godfrey, F. Yin, “Fast reconstruction of digital tomosynthesis using on-board images.” Med. Phys. 35, 2162 (2008).
L. Ren, J. Zhang, D. Thongphiew, D. J. Godfrey, Z. Wang, F. Yin, “A novel digital tomosynthesis (DTS) reconstruction method using a deformation field map.” Med. Phys. 35, 3110 (2008).
J. Maurer, D. J. Godfrey, Z. Wang, F. Yin, “On-board four-dimensional digital tomosynthesis: First experimental results.” Med. Phys. 35, 3574 (2008).
S. Yoo, Q. J. Wu, D. J. Godfrey, H. Yan, L. Ren, S. Das, W. R. Lee, F. Yin, “Clinical evaluation of positioning verification using digital tomosynthesis (DTS) based on bony anatomy and soft tissues for prostate image-guided radiation therapy (IGRT).” Int. J. Radiat. Oncol. Biol. Phys. 73(1):296-305 (2009).
J. Zhang, Q. J. Wu, D. J. Godfrey, T. Fatunase, L. B. Marks, F. Yin, “Comparing digital tomosynthesis to cone-beam CT for position verification in patients undergoing partial breast irradiation,” Int. J. Radiat. Oncol. Biol. Phys. 73(3):952-957 (2009).
Z. Chang, Q. Xiang, J. Ji, and F.F. Yin, “Efficient Multiple Acquisitions by Skipped Phase Encoding and Edge Deghosting (SPEED) Using Shared Spatial Information,” Magn. Reson. Med. 61:229–233 (2009).
Z. Chang, Q. Xiang, H. Shen, and F.F. Yin, “Accelerating Non-Contrast-Enhanced MR Angiography with Inflow Inversion Recovery Imaging by Skipped Phase Encoding and Edge Deghosting (SPEED),” Journal of Magnetic Resonance Imaging 31:757-765 (2010).
J Maurer, T Pan, F Yin, “Slow gantry rotation acquisition technique for on-board four-dimensional tomosynthesis.” Med Phys 37:921-933 (2010).
J. Jin, L. Ren, Q. Liu, J. Kim, N. Wen, H. Guan, B. Movsas, I. Chetty, “Combining scatter reduction and correction to improve image quality in cone-beam computed tomography (CBCT)”, Med. Phys. 37, 5634-5644, (2010).
Q. J. Wu, J. Meyer, J. Fuller, D. Godfrey, Z. Wang, J. Zhang, F. Yin, “Digital tomosynthesis for respiratory gated liver treatment: Clinical feasibility for daily image guidance,” Int. J. Radiat. Oncol. Biol. Phys.79(1):289-296 (2011).
I. Vergalasova, J. Cai, F.F. Yin, “A novel technique for markerless, self-sorted 4D CBCT: feasibility study,” Med Phys 39(3):1442-1451 (2012).
L. Ren, I. Chetty, J. Zhang, J. Jin, Q.J. Wu, H. Yan, D.M. Brizel, W.R. Lee, B. Movsas, F. Yin, “Development and clinical evaluation of a three-dimensional cone-beam computed tomography estimation method using a deformation field map,” Int J Radiat Oncol Biol Phys, 82(5): 1584-93 (2012).
L. Ren, F. Yin, I. Chetty, D. Jaffray, and J. Jin, “Feasibility study of a synchronized-moving-grid (SMOG) system to improve image quality in Cone-Beam Computed Tomography (CBCT)”, Med. Phys., 39(8), 5099-5110, (2012).
H. Li, W. Giles, L. Ren, J. Bowsher and F.F. Yin, “Implementation of Dual-Energy Technique for Virtual Monochromatic and Linearly Mixed CBCTs”, Med. Phys. 39(10), 6056-64, 2012.
Z. Chang, Q. Xiang, H. Shen, J. Ji and F.F. Yin, "Accelerating Phase Contrast MR Angiography by Simplified Skipped Phase Encoding and Edge Deghosting with Array Coil Enhancement,” Med. Phys., 39:1247-1252 (2012).
H. Li, W. Giles, J. Bowsher and F.F. Yin, “A Dual Cone-Beam CT System for Image Guided Radiotherapy: Initial Performance Characterization”, Med. Phys. 40(2), 021912, 2013.