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Current Fellows in the Radiation Epidemiology Branch

Meet the current fellows in the Radiation Epidemiology Branch and learn about research training opportunities.

Pragati Gole Advani, M.D., Dr.P.H., M.P.H. – Postdoctoral Fellow

Pragati Gole Advani, M.D., Dr.P.H., M.P.H. joined the Radiation Epidemiology Branch (REB) as a Cancer Research Training Award post-doctoral fellow in November 2017. Dr. Advani earned her doctoral degree from the University of Texas, School of Public Health in May 2016 with a major in health promotion and behavioral sciences and minor in cancer epidemiology. During doctoral program, she served as a Susan G. Komen pre-doctoral fellow and her dissertation examined disparities in patient adherence to surgical management of breast cancer and survivorship practices at the MD Anderson Cancer Center (MDACC). During the last year, Dr. Advani served as a first-year post-doctoral fellow in the Division of Radiation Oncology at the MDACC, where she worked on a population-based study examining the burden of local therapy (surgery and radiation) decisions and associated outcomes among older breast cancer patients. In May 2011, Dr. Advani earned her M.P.H from the Western Kentucky University with a concentration in Health education and Leadership studies. In October 2008, she earned her degree in Medicine from University of Seychelles. At the REB, Dr. Advani is working with Lindsay Morton, Ph.D., senior investigator, to broaden her experience in cancer survivorship research by investigating etiology for treatment-related second cancers.

 Scientific Publications – Pragati Advani

David Borrego, Ph.D. – Postdoctoral Fellow

David Borrego, Ph.D., joined the Radiation Epidemiology Branch (REB) as a postdoctoral fellow in June 2016. Dr. Borrego earned a B.S. in nuclear and radiological engineering (2010) and both an M.S. (2012) and Ph.D. (2016) in biomedical engineering with a concentration in medical physics from the University of Florida. His doctoral dissertation work focused on assessment of organ doses for fluoroscopically guided interventional procedures. Dr. Borrego’s main research interests are in Monte Carlo estimation of organ doses for patients undergoing radiography and fluoroscopy examinations and organ dose reconstruction based on occupational radiation exposure. In REB, Dr. Borrego is working closely with Choonsik Lee, Ph.D., investigator, REB, Martha Linet, M.D., M.P.H., senior investigator, REB, and Cari Kitahara, Ph.D., M.H.S., investigator, REB, on estimating organ and tissue-specific absorbed doses in members of the U.S. Radiologic Technologist Cohort and for use in epidemiological studies.

Scientific Publications – David Borrego

Yingxi (Cimo) Chen, M.D., Ph.D - Postdoctoral fellow

Yingxi (Cimo) Chen, M.D., Ph.D, joined the Radiation Epidemiology Branch (REB) as a postdoctoral fellow in September 2017. Dr. Chen received a Bachelor’s degree in Medicine (2011) from the Sichuan University and a M.P.H. (Res) (2013) and Ph.D in Epidemiology (2017) from the Australian National University. For her dissertation research, Dr. Chen estimated the burden of gastrointestinal infections in middle-aged and older adults, and investigated factors that were associated with adverse clinical outcomes using linked data from a large-scale cohort study to multiple administrative and clinical databases. In the Radiation Epidemiology Branch, Dr. Chen is working with Dr. Amy Berrington de González, D.Phil., Branch Chief and senior investigator, REB, on several projects with the goal of evaluating trends in disease incidence and mortality data.

Keith T. Griffin, M.S. – Postbaccalaureate Fellow

Keith T. Griffin, M.S., joined the Radiation Epidemiology Branch (REB) as a postbaccalaureate fellow in June 2017. He earned both his B.S. (2015) and M.S. (2016) in nuclear and radiological engineering from the Georgia Institute of Technology in Atlanta. Previously, Mr. Griffin worked two summers with the Center for Radiation Protection Knowledge team at Oak Ridge National Laboratory as an intern with the Nuclear Engineering Science Laboratory Synthesis Program. As part of his core research interests, he has employed Monte Carlo computational simulations to calculate dose coefficients associated with external exposure to hundreds of radionuclides in different environmental scenarios. Currently at NCI, he is working under the mentorship of Choonsik Lee, Ph.D, senior investigator, REB, to perform patient-specific computational dosimetry to explore the link between organ-absorbed dose and a patient’s body type during medical procedures or during environmental exposures.


Gleb Kuzmin, B.S. – Predoctoral Fellow

Gleb Kuzmin, B.S., joined the Radiation Epidemiology Branch (REB) as a predoctoral fellow in August 2015. Mr. Kuzmin received a B.S. in radiation physics from the University of Texas, Austin in May 2013. Currently, he is pursuing his Ph.D. in nuclear engineering with a specialization in health physics at Texas AM University. Throughout his education and research experience, Mr. Kuzmin has worked on various topics in medical physics, including medical dosimetry, computer phantoms, and Monte Carlo simulations. In REB, he is working under the mentorship of Choonsik Lee, Ph.D, investigator, and is focusing on projects related to organ dose reconstruction of proton therapy patients.

Byron Sigel, BA. – Postbaccalaureate Fellow

Byron Sigel, B.A., joined the Radiation Epidemiology Branch (REB) as a postbaccalaureate fellow in June 2017. Mr. Sigel graduated with a B.A. in biological chemistry from Grinnell College in May 2016. Prior to joining REB, he worked at the National Institute on Deafness and Other Communications Disorders with Dr. Thomas Friedman. Mr. Sigel previously worked as an intern at NTT Medical Center, Hiroshima University, Japan, and the Washington State University College of Pharmacy. At Washington State University College of Pharmacy, he worked on the formation of nanoparticles from 3LL lung carcinoma cells with Dr. Zhenjia Wang. Mr. Sigel is currently working with Lindsay Morton, Ph.D., Ph.D., senior investigator, REB, on the Long-Term Follow-Up Study of Retinoblastoma Survivors and the Childhood Cancer Survivor Study (CCSS).

Raquel Velazquez-Kronen, M.S. – Predoctoral Fellow

Raquel Velazquez-Kronen, M.S., joined the Radiation Epidemiology Branch (REB) as a predoctoral fellow in July 2016. She earned a B.S. in interdisciplinary studies at the University of Central Florida in 2012, and an M.S. in epidemiology in the Department of Epidemiology and Biostatistics from the University at Albany, SUNY (Year). Currently, she is pursuing her Ph.D. in cancer epidemiology at the University at Buffalo, SUNY. During her master’s training, she worked with the New York State Cancer Registry, assessing racial and ethnic disparities in breast and colorectal cancer diagnosis. Raquel was a previous summer fellow at REB. For her doctoral dissertation, she is working under the mentorship of Martha Linet, M.D., M.P.H., senior investigator, and Cari Kitahara, Ph.D., tenure-track investigator, on evaluating cancer risks associated with occupational radiation exposure in the United States Radiologic Technologists Cohort.

Scientific Publications - Raquel Velazquez-Kronen

Daphnée Villoing, Ph.D. – Postdoctoral Fellow

Daphnee Villoing, Ph.D.

Daphnée Villoing, Ph.D., joined the Radiation Epidemiology Branch (REB) as a postdoctoral fellow in April 2016. Dr. Villoing received an M.Sc. in biomedical engineering (2010), an M.Sc. in medical physics (2011), and a Ph.D. in medical physics (October 2015) from Paul Sabatier University, Toulouse, France.  Her doctoral dissertation work was focused on the impact of the Monte Carlo code GATE on imaging and dosimetric calculations for targeted radionuclide therapy. Dr. Villoing’s main research interests are Monte Carlo modelling, dosimetry of ionizing radiation in medical imaging and radiation therapy, radiation protection, and computational anthropomorphic models for medical imaging and radiation therapy. In REB, Dr. Villoing is working on the calculation of organ doses to patients who underwent diagnostic nuclear medicine procedures between the early 1960s and the present, under the supervision of Choonsik Lee, Ph.D. ,and Vladimir Drozdovitch, Ph.D. She is also involved in the evaluation of historical trends for occupational doses received by participants in the U.S. Radiologic Technologists Study and the U.S. Nuclear Medicine Technologists Pilot Study from 1960-2010, under the supervision of Cari Kitahara, Ph.D. Another component of her postdoctoral work is to estimate uncertainty and to increase dosimetric accuracy for organ doses for patients who underwent nuclear medicine procedures, using Monte Carlo radiation transport coupled with computational human phantoms, under Dr. Lee’s supervision.

Scientific Publications - Daphnée Villoing

Diana Withrow, Ph.D. – Research Fellow

Diana Withrow, Ph.D., joined the Radiation Epidemiology Branch (REB) as a postdoctoral fellow in May 2016 and promoted to Research Fellow in June 2018. Dr. Withrow earned her Ph.D. in epidemiology from the University of Toronto Dalla Lana School of Public Health in 2016. Working with Dr. Loraine Marrett, her doctoral research comprised the first national-level analysis of cancer survival among First Nations and Métis adults in Canada. In 2010, Dr. Withrow earned an M.Sc. in epidemiology from the London School of Hygiene and Tropical Medicine. Dr. Withrow’s research interests include socio-demographic and economic disparities in survival and survivorship, the role of therapy on second cancer risk, and the optimal application of survival analysis techniques to these research areas. At NCI, Dr. Withrow is working with Amy Berrington de González, D.Phil., Branch Chief and senior investigator, REB, and Lindsay Morton, Ph.D., senior investigator, REB. Dr. Withrow is currently working on several projects with the goal of characterizing patterns in second cancer incidence, particularly among breast cancer survivors. 

Scientific Publications - Diana Withrow

Yeon Soo Yeom, Ph.D. - Postdoctoral Fellow

Yeon Soo Yeom, Ph.D., joined the Radiation Epidemiology Branch (REB) as a postdoctoral fellow in March 2018. Dr. Yeom earned his B.S. (2011) and Ph.D. (2017) in nuclear engineering from Hanyang University, Seoul, South Korea, where he subsequently served as a postdoctoral researcher prior to joining REB. During his doctoral and postdoctoral training at Hanyang University, working with Prof. Chan Hyeong Kim, Dr. Yeom developed new adult male and female mesh-type reference computational phantoms for the International Commission on Radiological Protection (ICRP). Currently, Dr. Yeom is a full member on the International Commission of Radiological Protection (ICRP) Task Group 103 and a corresponding member on the ICRP Task Group 90. In REB, Dr. Yeom is working with Choonsik Lee, Ph.D., head of the Dosimetry Unit and senior investigator, REB, to expand his research experience to dosimetry studies for radiation epidemiology focusing on dose reconstruction for proton therapy patients.

Scientific Publications – Yeon Soo Yeom

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