CRP Faculty and Staff

CRP Faculty

Dr. Sun

Xiankai Sun, Ph.D.

Associate Professor, Radiology
Director, Cyclotron and Radiochemistry Program

Dr. Sun obtained his Ph.D. in supramolecular chemistry from the University of New Hampshire in 2000, under the supervision of Edward Wong, Ph.D. He conducted three years of postdoctoral training with Drs. Michael Welch and Carolyn Anderson and served on the junior faculty at Washington University School of Medicine in St. Louis. Dr. Sun joined the UT Southwestern faculty in 2004 and holds the Dr. Jack Krohmer Professorship in Radiation Physics.

Dr. Sun specializes in designing and synthesizing imaging probes and therapeutic agents for various diseases, including cancer and diabetes. His research focuses on developing biocompatible nanoscale scaffolds to enable multi-presentation of functionalities for detection and intervention of disease states; designing and synthesizing bifunctional chelator scaffolds for imaging signal amplification; and preparing targeted imaging probes for noninvasive assessment of pancreatic beta-cell mass and function. Dr. Sun's work is funded by the National Institutes of Health, the Juvenile Diabetes Research Foundation International, and the Cancer Prevention Research Institute of Texas.

Marianna Dakanali, Ph.D.

Marianna Dakanali, Ph.D.

Instructor, Radiology
Regulatory Affairs Officer, Cyclotron and Radiochemistry Program

Dr. Dakanali obtained her Ph.D. in total synthesis of bioactive natural products from the Agricultural University of Athens, Greece and National Center of Scientific Research “Democritos” in 2008, under the supervision of Professor E.A. Couladouros. She moved to the United States in 2009 and did three years of postdoctoral training with Professor E.A. Theodorakis at the University of California, San Diego in total synthesis of bioactive natural products, as well as the design and synthesis of fluorescent tracers.

She joined Dr. Xiankai Sun’s group at UT Southwestern in 2012 and was involved in the design and synthesis of Positron Emission Tomography (PET) tracers.

Immediately after joining UT Southwestern, Dr. Dakanali was involved with the design of the new cyclotron facility and was appointed as the regulatory affairs officer and as a research instructor at UT Southwestern in early 2015. Her primary role involves the oversight and coordination of the Cyclotron and Radiochemistry Program’s regulatory compliance, and is responsible for the preparation, assembly, and Food and Drug Administration (FDA) and Radioactive Drug Research Committee (RDRC) filings. Furthermore, she maintains the regulatory records and facilitates the clinical research of radiotracers.

Dr. Dakanali’s research interests involve the design and synthesis of novel radiotracers for the diagnosis of liver and lung fibrosis and cancer.

Guiyang Hao, Ph.D.

Guiyang Hao, Ph.D.

Assistant Professor, Radiology
Research Radiochemist, Cyclotron and Radiochemistry Program

Dr. Hao obtained his Ph.D. in radiopharmaceutical chemistry from Beijing Normal University, China. After two years of postdoctoral study in the National Institute of Radiological Sciences, Chiba, Japan, he joined Dr. Sun’s group in 2008. Dr. Hao is primarily responsible for the solid target work and new radiotracer development. His research focuses on the design and evaluation of novel imaging probes for oncology, neuroscience, and cardiovascular/metabolic diseases via nuclear and fluorescence imaging techniques.

Bob Hallgren

Robert Hallgren

Cyclotron Facility Manager

With an associate degree in aeronautics from Pittsburgh Institute of Aeronautics, Mr. Hallgren worked in the radiopharmaceutical industry for more than 30 years before he joined the CRP as the Cyclotron Facility Manager in 2013. An experienced engineer in cyclotron operations, maintenance, and design, Mr. Hallgren also has expertise in the GMP production of radioisotopes and radiotracers, design and implementation of new process and automation instruments. Mr. Hallgren’s responsibilities include maintaining the cyclotron, coordinating the production schedules of clinical and research isotopes, implementing radiation safety policies, exerting first-line administrative controls over the equipment and operation of the facility, and coordinating preventive maintenance services with manufacturers.

Khaled Nasr, Ph.D.

Khaled Nasr, Ph.D.

Senior Research Scientist
Radiochemistry Specialist, Cyclotron and Radiochemistry Program

Dr. Nasr earned his Ph.D. in Chemistry from the University of Massachusetts at Amherst in 2005. He then joined Massachusetts Institute of Technology for his postdoctoral training in biochemistry with research focus on design and characterization of superhelical peptides and proteins. In 2007, he joined Harvard Medical School and Beth Israel Deaconess Medical Center as a fellow in medicine gaining experience in design, synthesis of disease-specific NIR, MRI and SPECT imaging agents for cancer screening and staging. During that time, he developed and synthesized a small-molecule combinatorial library for cancer targeting and therapeutics, synthesized NIR Nerve-Specific contrast agents for image-guided surgery, and developed a high-throughput radioactive assay to measure antibody-binding kinetics.

He was recruited to UT Southwestern in 2011 where he has been in charge of the Translational Chemistry Laboratory for novel molecular imaging agent development and holds the position of Radiochemistry Specialist of the Cyclotron and Radiochemistry Program.

Nicklas Rydberg

Nicklas Rydberg, B.S.

Research Technician II, Radiology
Production Radiochemist, Cyclotron and Radiochemistry Program

Mr. Rydberg obtained his B.S. degree in Chemistry at the University of North Texas where he studied in an electrochemistry and materials research lab. He joined the Cyclotron and Radiochemistry Program at UT Southwestern in June 2016.

His primary responsibilities include operating and maintaining the quality control laboratory for the release of radiotracers, production of radiometals such as 64Cu and 89Zr, and preclinical tracer production. Mr. Rydberg also lends a hand with facility and equipment preventive maintenance and provides support for quality assurance and compliance with the facility GMP.

Rathan Subramaniam, M.D., Ph.D.

Rathan Subramaniam, M.D., Ph.D., M.P.H., FRANZCR, FACNM

Professor, Radiology
Medical Director, Cyclotron and Molecular Imaging Program

Dr. Subramaniam is the medical director of the Cyclotron and Molecular Imaging Program and holds the Robert W. Parkey, M.D. Distinguished Professorship in Radiology. He holds a Medical Degree (M.B.B.S.) from the Faculty of Medicine, University of Melbourne (Australia); a Master’s Degree in Clinical Education from the University of New South Wales (Sydney, Australia); a Master’s Degree in Public Health from Harvard University; and a Doctoral Degree in Radiology and Anatomy from the University of Auckland (New Zealand).

He completed his radiology residency training at Waikato Hospital (Hamilton, New Zealand), and then received advanced training in clinical trials of imaging through a fellowship program with the American College of Radiology Imaging Network, in magnetic resonance imaging (MRI) through a fellowship program at Canberra Hospital (Australia), and in nuclear radiology and neuroradiology through fellowship programs at Mayo Clinic College of Medicine.

Before becoming Chief of the Nuclear Medicine Division, Dr. Subramaniam was an Associate Professor of Radiology and Radiological Sciences, with secondary faculty appointments in Oncology, Otolaryngology and Head and Neck Surgery, and Health Policy and Management at Johns Hopkins University, where he also served as the director of the PET/CT clinical center and the program director of PET/CT fellowships.

His main research focus is translating novel PET radiopharmaceuticals in humans for oncology and neurological diseases and developing and standardizing therapy response assessment using PET/CT. He has been funded by industry, foundations, academic institutions, the National Institute of Health (NIH), and the Agency for Health Care Research and Quality (AHRQ).

He is the current Vice Chair for the American College of Radiology Commission on Nuclear Medicine and Molecular Imaging, and a past president of the American College of Nuclear Medicine and the Radiology Research Alliance.

Cristalla Edwards

Cristalla Edwards

Senior Administrative Assistant

Supporting Faculty and Staff

Jon Anderson, Ph.D.
Professor of Radiology
Director of Clinical Medical Physics

Sylvia Revell, CRM, CHES, RSO
Director, Business Continuity/Radiation Safety Program

Dan Crawley, M.B.A.
Administrative Director, Department of Radiology