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Discovering the causes of cancer and the means of prevention

David Borrego, Ph.D.

Independent Research Scholar
Division of Cancer Epidemiology and Genetics

NCI Shady Grove | 7E438


Dr. Borrego earned his Ph.D. in biomedical engineering with a concentration in medical physics from the University of Florida. He joined the Radiation Epidemiology Branch in 2016 as a postdoctoral fellow and became an Independent Research Scholar in 2019. Dr. Borrego’s research focuses on quantifying the radiation exposure to both patients and staff from medical imaging. His work and contributions to the field have been recognized by several awards, including the DCEG Fellowship Achievement award, DCEG Intramural Research Award, NCI Director’s Award for Population Science, and inaugural selection to the Independent Research Scholar Program of the NIH Office of Intramural Research. 

Research Interests

Dr. Borrego’s research focuses on improving our understanding of ionizing radiation, associated health risks, and the development of models to clarify how ionizing radiation, like medical x-rays from radiography and fluoroscopy, deposits energy in the tissues of the human body.

Medical Radiation Exposures

Fluoroscopically guided interventional (FGI) procedures utilize real-time fields of ionizing radiation to guide catheters through blood vessels to an interventional site during medical procedures. The number of FGI procedures performed within the U.S. has risen sharply – a threefold increase from 1970 to 2010. This increase is attributed to improved patient outcomes, decreased morbidity compared to surgery, and improvements in x-ray imaging systems.

Dr. Borrego is addressing concerns about FGI by developing models of exposure assessment that consider demographic and procedural information, literature-reported radiation exposure data, and physical measurements of x-ray tube output. These data are then used in Monte Carlo simulations of radiation transport coupled with computational models of the human anatomy to estimate the radiation dose in organs and radiosensitive tissues. This work may 1) improve future epidemiological studies of radiogenic risks and 2) inform interventional cardiologists in strategizing and implementing changes in imaging techniques to reduce radiation risks without compromising medical benefits.

Occupational Radiation Exposures

The radiation exposure to medical staff performing or assisting with FGI procedures is among the highest in medical practice. Working in this environment for a prolonged period without proper radiation safety training or the use of personal protective equipment may lead to occupational doses in excess of regulatory limits. High-quality dosimetry information for occupational exposure is needed to better inform radiation protection practices and for application in epidemiological studies on radiation-related risks of cataracts, cancer, and other serious diseases. However, past studies of these workers reported doses per-procedure and not annual occupational doses or trends in doses over time.

Dr. Borrego conducted the largest study in the U.S. on occupational doses and trends over time for medical staff assisting or performing FGI procedures. This study has revealed the importance of compliance and accurate badge placement, to reduce uncertainties in exposure assessment. Currently, Dr. Borrego is leading an effort to use readings from personal monitoring devices and Monte Carlo methods to better inform the exposure assessment in large cohorts of occupationally exposed workers, such as the U.S. Radiologic Technologists Study.