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Medical Physics Research

The mission of physics research is to develop new techniques and investigate new methodologies to continuously improve treatment planning and evaluation methods, target localization and verification accuracy and treatment delivery precision.

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Novel Radiotherapy Techniques

Qiuwen Wu, Zheng (Jim) Chang, Sua Yoo, Fang-Fang Yin

Research Overview

As modern radiation therapy evolves, new and novel techniques are proposed and/or established treatment modality is applied to new area. 

Feasibility study, technical validations and clinical implementations are the subjects of many physics research. Quantitative evaluation of the new techniques against established standard methods are necessary to prove the clinical potential. Active areas of research in this group include but are not limited to the following:

  • Dynamic electron arc beam therapy with synchronized couch motion for tumors at shallow depth

  • Application of volumetric modulated radiation therapy (VMAT) to partial breast irradiation

  • Image-guided single fraction partial breast radiotherapy

Funding Sources


Selected Publications

Jian-Jian Qiu, Zheng Chang, Q. Jackie Wu, Sua Yoo, Janet Horton, Fang-Fang Yin, Impact of Volumetric Modulated Arc Therapy (v-MAT) Treatment Technique for Partial Breast Irradiation, International journal of radiation oncology, biology, physics 2010; 78:288-296.

Manisha Palta, Sua Yoo, Justus D. Adamson, Leonard R. Prosnitz, Janet K. Horton, Preoperative Single Fraction Partial Breast Radiotherapy for Early-Stage Breast Cancer, International journal of radiation oncology, biology, physics 2012; 82:37-42.

3D Dosimetry and Optical Bio-Imaging

Mark Oldham


The lab pursues two main avenues of research. The first involves developing and applying new methods of high resolution 3D dosimetry. A range of uniquely capable state-of-the-art 3D dosimetry systems have been developed with funding support from the National Institute of Health. These systems are currently being applied to a diverse range of challenges in both the clinical (radiation therapy) and research domains. The second direction focuses on developing the new optical bio-imaging techniques of optical-computed-tomography (optical-CT), and optical-emission-computed-tomography (optical-ECT). These techniques have the potential to provide uniquely useful information on biological processes in bulk tumor and tissue samples.

4D Radiotherapy and Tumor Motion Management

Jing Cai, Fang-Fang Yin, Lei Ren, Zheng (Jim) Chang, Zhiheng Wang, Jackie Wu

Research Overview

The management of respiratory motion in radiation oncology is one subject of important physics research. Respiratory motion affects all tumor sites in the thorax and abdomen.

Our research aims to improve the management of tumor motion via developing and evaluating novel 4D imaging techniques (4D-MRI, 4D-CBCT, 4D-PET, 4D-DTS) and 4D dose calculation methodologies, modeling and predicting lung and tumor respiratory motion, assessing treatment outcome of moving tumors, investigating correlations between internal tumor motion and external surrogate motion and clinically implementing new motion management techniques.

Funding Sources

Golfers Against Cancer (GAC) Foundation
Philips Health System
Varian Medical System

Selected Publications

Cai J, Chang Z, O’Daniel J, Yoo S, Ge H, Kelsey C, Yin FF. Investigation of Sliced Body Area (SBA) as Respiratory Surrogate. J Am Clin Med Phys 2013;14(1):71-80.

Panta RK, Segars WP, Yin FF, Cai J. Implementing 4D-XCAT Phantom for 4D Radiotherapy Research. J Can Res Ther 2012;8:565-570.

Vergalasova I, Cai J, Yin FF. A novel technique for markerless, self-sorted 4D CBCT: feasibility study. Med Phys 2012 39(3):1442-1451.

Cai J, Chang Z, Wang Z, Segars WP, Yin FF. Four-dimensional Magnetic Resonance Imaging (4D-MRI) using Body Area as Internal Respiratory Surrogate: a Feasibility Study. Med. Phys 2011 38(12):6384-6394.

Wu QJ, Thongphiew D, Wang Z, Willett C, Marks L, Yin FF, Development of a 4D dosimetry simulation system in radiotherapy, Int. J. Biomedical Engineering and Technology, Vol. 8, Nos. 2/3, 201, 230-244 2012.

Quality Assurance of Radiotherapy

Jennifer O’Daniel, Zheng (Jim) Chang, Mark Oldham, Lei Ren, Jackie Wu, Ph.D., Fang-Fang Yin, Sua Yoo

Research Overview

Quality assurance (QA), both equipment-specific and patient-specific, is an essential component of safe radiotherapy treatments.


Our research team is focused on (1) improving the efficiency and effectiveness of current QA techniques and (2) developing new QA methods for novel technology. Current research projects include developing 3D QA tools, determining the correlation between traditional QA analysis criteria and the accuracy of patient treatment, quantifying the accuracy of novel radiotherapy devices (ex. flattening-filter free linear accelerator for breast radiotherapy), and creating methods for the QA of adaptive radiotherapy.

Funding Sources

Scandidos, Inc.

Selected Publications

Dube S, O’Daniel J, and Orton C. Point/Counterpoint: TG-142 is unwarranted for IGRT QA. Med Phys 2013; 40(1): 3987.

Chang Z, Bowsher J, Cai J, Yoo S, Wang S, Adamson J, Ren L, and Yin FF. Imaging system QA of a medical accelerator, Novalis Tx, for IGRT as per TG 142: Our 1 year experience. J Appl Clin Med Phys 2012; 13:113-140.

Oldham M, Thomas A, O’Daniel J, Juang T, Ibbott G, Adamovics J, and Kirkpatrick JP. A quality assurance method that utilitzes 3D dosimetry and facilitates clinical interpretation. Int J Radiat Oncol Biol Phys 2012; 84(2): 540-546.

O’Daniel J, Das S, Wu QJ, and Yin FF. Volumetric-Modulated Arc Therapy: Effective and Efficient End-to-End Patient-Specific Quality Assurance. Int J Radiat Oncol Biol Phys 2012; 84(5): 1567-74.

Chang Z, O’Daniel J, Yin FF. Quality assurance in adaptive radiation therapy, in Adaptive Radiation Therapy, edited by X. Allen Li. CRC Press, Taylor & Francis Group LLC, 2011.

Chang Z, Liu T, Cai J, Chen Q, Wang Z, and Yin FF. Evaluation of integrated respiratory gating systems on a Novalis Tx system. J Appl Clin Med Phys 2011; 12: 71-79.


Oana Craciunescu, Jing Cai, Justus Adamson, Beverly Steffey, Sheridan Meltsner, Mark Oldham

Research Overview

Image-guidance plays an important role in modern radiation therapy, predominantly in external beam planning and delivery. In recent years, with the advent of high/pulsed dose rate afterloading technology, advanced treatment planning systems, and CT and MRI compatible applicators, image-guided adaptive brachytherapy treatments (IGABT) are now achievable. With image guidance, the target can be delineated more precisely, resulting in delivering more controlled doses of radiation to the target while sparing surrounding healthy tissue.

Our group has been active in understand the benefits of IGARBT in general, MR-based in particular with emphasis on: applicator characterization, image registration, planning techniques in general, and the use of inverse planning in particular, role of model-based dose calculation algorithms, adaptive strategies, intrafraction variability, in-vivo dosimetry, dose summation with external beam treatments.

Funding Sources

Radiation Oncology Department Support

Selected Publications

R. McMahon, T. Zhuang, B. Steffey, H. Song, O. Craciunescu,” Commissioning of Varian Ring & Tandem HDR Applicators: Reproducibility and Inter-Observer Variability of Dwell Position Offsets”, Journal of Applied Medical Physics, vol 12, (4), 50-62, 2011.

Justus Adamson, Joseph Newton, Beverly Steffey, Jing Cai, Mark Oldham, Junzo Chino, and Oana Craciunescu, “Commissioning a CT compatible LDR tandem and ovoid applicator using 3D dosimetry, Medical Physics, 39, 4515-4523, 2012.

Pierquet M, Craciunescu O, Steffey B, Song H, Oldham M, “On the Feasibility of Verification of 3D Dosimetry Near Brachytherapy Sources Using PRESAGE/Optical-CT”, J. Phys.: Conf. Ser. 250 012091, 2010.

Chino J, Maurer J, Steffey B, Cai J, Adamson J, Craciunescu O, “IS AN MRI REQUIRED ON EACH FRACTION? AN EXPERIENCE WITH MRI GUIDED BRACHYTHERAPY FOR CERVICAL CANCER”, O. Radiotherapy and Oncology vol. 103 May, 2012. p. S107.

Craciunescu, J. Sánchez Mazón, L. Lan, J. Maurer, B. Steffey, J. Cai, J. Adamson, J. Chino, DOSIMETRIC IMPACT OF NOT CORRECTING FOR THE DISTAL SHIFT REPORTED IN VARIAN TANDEM AND RING (T&R) APPLICATORS”, J. Radiotherapy and Oncology vol. 103 May, 2012. p. S137

B. Steffey, O. Craciunescu, J. Cai, J. Adamson, J. Chino, “CLINICAL ASSESSMENT OF THE HDR CAPRI APPLICATOR”, Radiotherapy and Oncology vol. 103 May, 2012. p. S142.

J Adamson, J Newton, B Steffey, J Cai, J Adamovics, M Oldham, J Chino, and O Craciunescu, “Commissioning a CT Compatible LDR T&O Applicator Using Analytical Calculation with ID and 3D Dosimetry”, Med. Phys. 39, 3612 (2012).

J. Cai, J. Chino, Y. Qin, T.R. De Oliveira, J. Adamson, B. Steffey, O. Craciunescu, Feasibility of MR-alone-based Brachytherapy Treatment Planning Using a Titanium Tandem and Ring Applicator for Cervical Cancer, International Journal of Radiation Oncology*Biology*Physics, Volume 84, Issue 3, Supplement, 1 November 2012, Page S803.

Junzo Chino MD, Sheridan Meltsner PhD, Yun Yang PhD, Beverley Steffey MS, Jing Cai PhD, and Oana Craciunescu PhD, “Vaginal Dose in the Era of Image Guided Brachytherapy”, ABS 2013.

Oana Craciunescu PhD , Lei Ding, Jing Cai PhD, Beverley Steffey MS, Sheridan Meltsner PhD, Yun Yang PhD, Junzo Chino MD, “Intelligent Dose Summation from Multimodality Treatment of Cervical Cancer: A Case Study”, ABS 2013.

Y. Yang, S. Yan, J. Cai, B. Steffey, S. Meltsner, A. Thomas, F. Yin, O. Craciunescu, “Comprehensive Assessment Of Dose Variation Due to Ir-192 Source Position Within Varian Ring Using Monte Carlo Methods”, AAPM 2013.

Adria Vidovici et al, “Evaluation of a novel radiochromic dosimetry system for in-vivo dose verification in organs at risk in HDR intracavitary gynecological brachytherapy”, AAM 2013.

Research and Education Symposia

Craciunescu, O, Cai, J, Kirisits, C., de Leeuw, A., “Image Guided Adaptive Brachytherapy for Cervical Cancer”, AAPM, July 2012.

Craciunescu, O,Cai, J., Chino, J., “Implementing MR-Guided Adaptive Brachytherapy for Cervical Cancer”, AAPM 2013.

Knowledge Planning and Decision Support

Q. Jackie Wu, * Yaorong Ge, Qiuwen Wu, Fang-Fang Yin
* College of Computing and Informatics, UNC-Charlotte, Charlotte, NC

Research Overview

In current practice, IMRT/VMAT planning takes an experienced planner 1-6 hours, using an iterative, trial-and-error approach. Even with this effort the search for patient-specific optimal organ sparing is still strongly influenced by planner’s experience. Significant variations in plan quality have been observed at different institutions. Experienced centers are generally more capable of maximizing the dosimetric advantages of IMRT/VMAT. The knowledge and experience of an IMRT/VMAT treatment team is of great importance to realize the full benefits of this advanced technology.

This project focuses on developing knowledge models for guiding IMRTVMAT planning. The models are carefully developed from databases of high quality clinical plans, guidelines from clinical studies, as well as personal experience of expert planners. This comprehensive modeling approach with a strong focus on clinical practice is a distinguishing feature of this technology. These advanced models, will (1) capture human expert knowledge in designing high quality plans, (2) predict the optimal organ sparing that is specific to an individual patient, and (3) guide the design of the treatment plan to achieve optimal dose distribution with improved efficiency.

Funding Sources

Varian Medical System

Selected Publications

Wu QJ, Li T, Wu Q, and Yin FF. Adaptive radiation therapy: technical components and clinical applications. Cancer J 17:182-9, 2011.

Li T, Thongphiew D, Zhu X, Lee WR, Vujaskovic Z, Yin FF, and Wu QJ. Adaptive prostate IGRT combining online re-optimization and re-positioning: a feasibility study. Phys. Med. Biol. 56: 1243, 2011.

Zhu X, Ge Y, Li T, Thongphiew D, Yin FF, and Wu QJ. A planning quality evaluation tool for prostate adaptive IMRT based on machine learning, Med. Phys. 38, 719: 723, 2011.

Li T, Zhu X, Thongphiew D, Lee WR, Vujaskovic Z, Wu Q, Yin FF, and Wu QJ. On-line Adaptive Radiation Therapy (ART): Feasibility And Clinical Study, J Oncol., vol. 2011.

Yuan L, Ge Y, Lee WR, Yin FF, Kirkpatrick JP, Wu QJ. Quantitative analysis of the factors which affect the interpatient organ-at-risk dose sparing variation in IMRT plans. Med Phys. 2012 Nov; 39(11):6868-78.

Robotic SPECT for Functional and Molecular Imaging Onboard Radiation Therapy Machines

James Bowsher, Fang-Fang Yin

Research Overview

Onboard imaging – as the patient is in position for treatment – is essential in radiation therapy. Currently onboard imaging is performed predominantly by cone-beam CT, which has limited capability for functional and molecular (F&M) imaging. Yet cancer is distinguished from surrounding healthy tissue largely by F&M characteristics. The purpose of this work is to develop single-photon emission computed tomography (SPECT) methods for F&M imaging onboard radiation therapy machines. These methods may also improve imaging for other tasks in which only a limited region of the full patient cross-section is of primary interest, such as in nuclear cardiology.

Funding Sources

NIH National Cancer Institute

Selected Publications

S Yan, J Bowsher, F Yin: Respiratory Sorted Imaging Using Region-Of-Interest Robotic Multi-Pinhole SPECT System. Presentation at the 55th Annual Meeting of the American Association of Physicists in Medicine, August 4-8, Indianapolis, IN, 2013. Medical Physics, 2013.

S Yan, J Bowsher, S Yoo, F Yin: On-Board Robotic Multi-Pinhole SPECT System for Prone Breast Imaging. Presentation at the 55th Annual Meeting of the American Association of Physicists in Medicine, August 4-8, Indianapolis, IN, 2013. Medical Physics, 2013.

J Bowsher, S Yan, F Yin: Robotic Multi-Pinhole Scenarios for SPECT Molecular and Functional Imaging Onboard and in Other Applications. Presentation at the 55th Annual Meeting of the American Association of Physicists in Medicine, August 4-8, Indianapolis, IN, 2013. Medical Physics, 2013.

S Yan, J Bowsher, F Yin: Functional and Molecular Imaging of the Axilla as the Patient Is in Position for Radiation Therapy Using a Robotic Multi-pinhole SPECT System. International Journal of Radiation Oncology Biology Physics 84(3) S247-S8, 2012.

S Yan, J Bowsher, W Giles, F Yin: A Line-Source Method for Aligning Onboard-Robotic-Pinhole and Other SPECT-Pinhole Systems. Presented at the 54th Annual Meeting of the American Association of Physicists in Medicine, July 29 - Aug 2, Charlotte, NC, 2012. Medical Physics 39(6) 4011, 2012.

J Bowsher, S Yan, J Roper, W Giles, F Yin: A Robotic Multi-Pinhole SPECT System for Onboard and Other Region-Of-Interest Imaging. Presented at the 54th Annual Meeting of the American Association of Physicists in Medicine, July 29 - Aug 2, Charlotte, NC, 2012. Medical Physics 39(6) 3887, 2012.

JE Bowsher, S Yan, JR Roper, WM Giles, F Yin: SPECT Imaging Onboard Radiation Therapy Machines. Invited Talk at SPIE Optics and Photonics: Optical Engineering and Applications: Medical Applications of Radiation Detectors, August 21-25, 2011, San Diego, CA.

Radiosurgery Research

Justus Adamson, William Giles, Fang-Fang Yin

Research Overview

The radiosurgery research group is focused on improving treatment planning techniques and quality assurance methods for linear accelerator based radiosurgery.  

Conformal Arc Informed Volumetric Modulated Arc Therapy (CAVMAT)
One current direction includes developing and refining a novel approach to stereotactic radiosurgery treatment planning for multiple brain metastases called Conformal Arc Informed VMAT (CAVMAT). When treating brain metastases there are several techniques that may be used, such as dynamic conformal arcs and VMAT. While effective and intuitive, dynamic conformal arcs suffer from a lack of modulation flexibility and extended treatment times. Conversely, VMAT is highly flexible and conformal, but may produce overly modulated and unintuitive MLC trajectories. In multi-target cases these unintuitive trajectories can lead to dose bridging between targets and irregular shaped isodose distributions. 

CAVMAT is a hybrid technique, combining the intuitive MLC motions of dynamic conformal arc plans with the flexibility of VMAT inverse optimization. CAVMAT produces more intuitive dose distributions, reduces dose bridging and substantially spares healthy tissue without compromising plan quality.

Whereas VMAT may partially block targets or create unnecessary MLC openings, CAVMAT divides targets into subgroups, prioritizing effective collimation. The subgroups serve as a starting point for inverse optimization.


VMAT dose bridging (left) and more intuitive and concentric distribution of CAVMAT (right)

Fast and Comprehensive Verification of Radiation and Imaging Isocenter
We are also working on developing a fast and comprehensive method to directly measure radiation isocenter uncertainty and coincidence with the kV-CBCT imaging system using 3D polymer gel dosimetry. We utilize novel N-isopropylacrylamide (NIPAM) gel dosimeters which have the unique characteristic of manifesting delivered dose as a change in density, and can thus be read out using CT and on-board CBCT.  For comprehensive isocenter verification, a NIPAM dosimeter is irradiated at eight unique couch/gantry combinations, CBCT images are immediately acquired, radiation profile is detected per beam and the displacement from the imaging isocenter is quantified using MATLAB analysis. Setup, irradiation and CBCT readout can be performed within a typical QA slot. 


Left: Image of NIPAM gel dosimeter immediately after irradiation. Right: Orthogonal views (top) through the dosimeter for the isocenter verification of a 5mm diameter MLC field.

3D plots of each beam for (a) an ideal case with no uncertainty in radiation isocenter and perfect alignment with imaging isocenter and (b) the measured beam trajectories for the 5mm diameter MLC field

Advanced Techniques for Stereotactic Radiosurgery

Zhiheng Wang, Fang-Fang Yin, Jim Chang, Justus Adamson, Hui Yan, Lei Ren, Qing Chen

Research Overview

Stereotactic rediosurgery (SRS) requires treatment with high precision. It's always a challenge during SRS planning, localization and delivery to ensure the required high accuracy. This work aims to use advanced technologies such as image guidance and high definition MLC to develop techniques for precise and efficient SRS treatment.

Funding Sources

Brainlab AG
Varian Medical System

Selected Publications

Z. Wang, J. Kirkpatrick, Z. Chang, J. O’Daniel, C. Willett, F-F. Yin. RapidArc for Treatment of Intracranial Multi-Focal Stereotactic Radiosurgery. ISRS 2009
Z. Wang, J. Nelson, S. Yoo, Q. J. Wu, J. Kirkpatrick, L. B. Marks, F-F Yin.

Refinement of Treatment set up and Target Localization Accuracy Using 3D Cone Beam CT for Stereotactic Body Radiation Therapy. Int. J. Radiat. Oncol. Biol. Phys. 73(2), p.571-7, (2009).

F-F. Yin, Z. Wang, S. Yoo, Q. J. Wu, J. Kirkpatrick, N. Larrier, J. Meyer, C. G. Willett, L. B. Marks, Integration of Cone-Beam CT in Stereotactic Body Radiation Therapy. Tech. Cancer Res. Treat. 7 (2), p.133-140, (2008).

Wang Z, Thomas A, Newton J, Ibbott G, Deasy J, Oldham M. Dose Verification of Stereotactic Radiosurgery Treatment for Trigeminal Neuralgia with Presage 3D Dosimetry System. J Phys Conf Ser. 2010 Dec 7;250(1). pii: 012058.

Z. Wang, Q. J. Wu, L. B. Marks, N. Larrier, and F-F. Yin. Cone-Beam CT Localization of Internal Target Volumes for Stereotactic Body Radiotherapy of Lung Lesions. Int. J. Radiat. Oncol. Biol. Phys. 69(5), p.1618-24, (2007).

Image-Guided Radiation Therapy

Zheng Chang, Qiuwen Wu, Sua Yoo, Fang-Fang Yin

Research Overview

Recent developments in image-guidance and immobilization enable target localization with increased accuracy, in order to deliver radiation more precisely to the tumor while sparing adjacent healthy tissue. With such improvements in imaging techniques, image guided radiation therapy (IGRT) has been widely adopted into clinical practice. Current active research projects includes 6 degree-of-freedom image guided SRS/SBRT, deformable registration for breast SBRT and 3D surface imaging for head and neck cancer radiotherapy.


Selected Publications

Jinli Ma, Zheng Chang, Q. Jackie Wu , Zhiheng Wang, John P. Kirkpatrick, Fang-Fang Yin, ExacTrac X-ray 6 Degree-of-Freedom Image Guidance for Intracranial Noninvasive Stereotactic Radiotherapy: Comparison with kilo-voltage Cone-beam CT, Radiotherapy and Oncology 2009; 93:602–608.

Zheng Chang, Zhiheng Wang, Jinli Ma, Jennifer C. O’Daniel, John Kirkpatrick, and Fang-Fang Yin, 6D Image Guidance for Spinal Noninvasive Stereotactic Body Radiation Therapy: comparison between Exactrac X-ray 6D with Kilo-voltage Cone Beam CT, Radiotherapy and Oncology. 2010; 95: 116–121.

Olga Gopan, Qiuwen Wu, Evaluation of the accuracy of a 3D surface imaging system for patient setup in head and neck cancer radiotherapy.Int J Radiat Oncol Biol Phys. 2012;84(2):547-52.

Novel Image Acquisition and Reconstruction Techniques for IGRT

Lei Ren, Devon Godfrey, Hui Yan, Jing Cai, Zheng Chang, Jackie Wu, Sua Yoo, James Bowsher, Fang-Fang Yin

Research Overview

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.
Funding Sources

Varian Medical System

Selected Publications

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.