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Department of Radiology Heersink School of Medicine

Loretta M. Johnson, Ph.D., DABR

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Loretta M. Johnson, Ph.D., DABR, FAAPM

Division Director, Physics and Engineering
Assistant Professor, Division of Physics and Engineering
lorettajohnson@uabmc.edu
205-934-7592  | Location: GSB 301-E1

Loretta M. Johnson, Ph.D., earned a bachelor’s degree in physics from Grinnell College, followed by a Ph.D in physics from The University of Kansas. Enthusiasm for teaching led her to nearly ten years of teaching at small liberal arts colleges. Throughout this time, Dr. Johnson’s research focused on how existing experimental results limited models beyond the Standard Model of particle physics, specifically with respect to neutrinos.

Dr. Johnson then returned to school to earn an M.S. in medical physics from University of Oklahoma – Health Sciences Center, where a former UAB fellow’s advice led her to continue her clinical training in the post-doctoral fellowship/residency program at the University of Alabama at Birmingham.

After obtaining experience in consulting medical physics in the Kansas City area and in private hospital-based medical physics in the Dallas/Ft. Worth area (where she was also the radioactive materials Radiation Safety Officer for a hospital), Dr. Johnson has returned to UAB as an Assistant Professor in the Division of Medical Physics and Engineering.

Dr. Johnson is an active member of the American Association of Physicists in Medicine for which she serves on several committees, including being the Chair of the New Professionals Subcommittee and Vice Chair of the Physics Education Task Force Subcommittee (which produces RSNA/AAPM Physics Modules).

Dr. Johnson is also an active member of the ACR. She recently chaired the most recent update of the Technical Standard for Medical Physics Performance Monitoring of SPECT-CT Equipment (not yet released), and she participates in summarizing exam doses with the Subcommittee on Appropriateness Criteria - Radiation Exposure.

At UAB, she will be involved with radiography, fluoroscopy, CT, and MRI quality assurance programs and will assist with teaching residents. Her current research interests are optimization in radiography, fluoroscopy, and mammography, including how dual energy imaging, contrast enhancement, and tomosynthesis affect image quality and dose.

Contact Information

Administrative Support:
Teresa Worden
P: 205-934-0071

Xizeng Wu, Ph.D., DABR

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Xizeng Wu, Ph.D., DABR

Retired Professor Emeritus, Division of Physics and Engineering

Xizeng Wu, received his Ph. D. in theoretical high-energy physics in 1983 from City University of New York, and had his two-year postdoctoral training at Massachusetts Institute in 1983-1985, and another postdoctoral training at University of Cincinnati in 1985-1988. He received his medical physics fellowship training here at UAB in 1988, and he joined the faculty of the department in 1989.

Dr. Wu has a broad background and experiences in medical imaging physics. The mammography radiation dosimetry tables developed by him and colleagues have been adopted as the standard dosimetry tables in the U.S. since 1994. These dosimetry tables are used by medical physicists of this country in their routine works for the regulation compliance and mammography techniques optimization. In recent years his research focuses on the x-ray phase sensitive imaging, an emerging imaging field that attracts extensive research efforts over the world. He serves as the principal investigator or co-investigator for several federal grants to develop phase contrast imaging techniques. His works in this research field are widely cited. Dr. Wu participated in radiology resident teaching through several CT physics courses every year until his retirement in 2020.

Selected Publications:

Wu X, Barnes GT, Tucker DM: Spectral dependence of glandular tissue dose in screen-film mammography. Radiology 179:143-148, 1991.

Wu X: Line shapes of magnetization transfer via cross relaxation. Journal of Magnetic Resonance 94:186-190, 1991.

Wu X, Gingold EL, Barnes GT and Tucker DM: Normalized average glandular dose in Molybdenum target-Rhodium filter and Rhodium target-Rhodium filter mammography. Radiology 193:83-89, 1994.

Wu X and Liu H: A general theoretical formalism for X-ray phase contrast imaging, Journal of X-Ray Science and Technology 11: 33-42, 2003.

Wu X and Liu H: Clinical implementation of phase contrast x-ray imaging: theoretical foundation and design considerations, Medical Physics 30: 2169-2179, 2003.

Wu X, Liu H and Yan A, X-ray Phase-Attenuation Duality and Phase Retrieval, Optics Letters 30: 379-381, 2005.

Wu X, Liu H: X-Ray cone-beam phase tomography formulas based on phase-attenuation duality, Optical Express 13: 6000-6014, 2005.

Wu X, Liu H: Clarification of aspects in in-line phase-sensitive x-ray imaging, Medical Physics 34: 737-743, 2007.

Yan A, Wu X and Liu H, “Quantitative theory of X-ray interferometers based on dual phase grating: fringe period and visibility,” Optics Express 26: 23142-23155, 2018.

Yan A, Wu X, Liu H, “Sample phase gradient and fringe phase shift in dual phase grating X-ray interferometry,” Optics Express 27: 35437-35447, 2019.

M. Ghani, X. Wu, L. Fajardo, Z. Jing, B. Zheng, M. Wong, F. Omoumi, Y. Li, A. Yan, P. Jenkins, S. Hills, Y. Qiu, L. Linstroth, H. Liu, “Development and Pre-Clinical Evaluation of a Patient-Specific High Energy X-ray Phase Sensitive Breast Tomosynthesis System”, Medical Physics, 2020 , Accepted.

Daniel J. Staton, Ph.D., DABR

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Daniel J. Staton, Ph.D., DABR

Adjunct Instructor, Division of Physics and Engineering
staton@physica-imaging.com
Dr. Staton is a fellowship-trained medical physicist that teaches radiologic physics.  

Wlad T. Sobol, Ph.D., DABR, DABMP, FAAPM

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Wlad T. Sobol, Ph.D., DABR, DABMP, FAAPM

Retired Professor Emeritus, Division of Physics and Engineering
Dr. Sobol provides expertise in imaging physics, supporting the clinical, instructional and research activities in Magnetic Resonance Imaging. He teaches a course in MRI physics for radiology residents. His interests include studies of MRI artifacts and ways to minimize them, optimization of fast imaging techniques, NMR tissue characterization, and mechanisms of relaxation enhancement by MR contrast agents.

 

 

  1. David M. Gauntt, Ph.D., DABR, FAAPM
  2. Gary T. Barnes, Ph.D., DABR, FAAPM, FACR
  3. Jian-xiong Wang, Ph.D., CCPM-MRI

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