Brian A. Thomas, M.S.
Vice President, Senior Scientist
Mr. Thomas has a background in nuclear engineering with specific training in health physics and internal dosimetry concepts and calculation techniques. He has more than 26 years of experience in performing quantitative dose and risk assessment, including uncertainty analyses. He has expert capabilities in model development, programming, risk analysis, uncertainty analysis, and database management. He has assisted in the reconstruction of the models and assumptions used to calculate individual doses in reviews of historic dose reconstructions, as well as programming custom estimates of individual exposure, dose, and risk. He played an active role in a variety of risk assessments requiring extensive calculations, thorough uncertainty analyses, or interactive computer codes. He is the principal programmer at ORRisk responsible for all web-based implementations of scientific computer codes.
Mr. Thomas has been involved in numerous radiological dose and risk assessment studies. He was a lead person in the assessment of doses and risks to members of the public from releases of tritium from the National Tritium Labeling Facility (NTLF) at Lawrence Berkeley National Laboratory. As part of the Oak Ridge Dose Reconstruction, he performed a conservative screening analysis to identify radionuclides and exposure pathways resulting from contaminant release from the Oak Ridge National Laboratory to the Clinch River and developed user-friendly models to quantify the uncertainty in the offsite dose and health risks. He contributed to the development of an Interactive Risk and Dose calculator (IRAD) for the Oak Ridge community. He provided programming support to the University of Utah in the estimation of thyroid doses to approximately 4,000 individuals included in the NTS Thyroid Cohort Study. He has also participated in many research aspects related to the development of radiation risk models used in the online computational tools developed by ORRisk and was responsible for the quality assessment/quality control (QA/QC) efforts for these projects. He has programming expertise in the Analytica software environment for building, exploring, and sharing quantitative decision models. He also has expertise in many web-based languages, as well as familiarity with the management and manipulations of complex databases (e.g. SQL).
Mr. Thomas is currently providing support to the National Aeronautics and Space Administration (NASA) for the estimation of health risks due to exposures to space radiation. With ORRISK, he provided support for the development of a Risk Analysis Environment (RAE), which has adapted and integrated the NASA Space Cancer Risk Model (NSCR) into a new operational workflow to allow NASA’s Space Risk Analysis Group to perform assessments of risk of cancer incidence and mortality from exposures to radiation during space missions, training flights and diagnostic medical imaging necessary for flight certification. He provides ongoing support for the implementation of new features into the user interface, and for modeling, development, and testing of scientific aspects related to risk assessment in a research version of RAE.
Mr. Thomas is part of a scientific team that is investigating the impacts of radiation exposure to humans as part of the Canadian Fluoroscopy Cohort Study (CFCS), a cohort of approximately 64,000 patients from Canada who were treated for tuberculosis between 1930 and 1969. He was involved in programming the new Fluoroscopy X-rays Organ-Specific Dosimetry System (FLUXOR) for estimation of organ doses to members of the cohort. FLUXOR accounts for factors such as patient age, machine settings, timing of the exposures, and dose fractionation.
Mr. Thomas collaborated in programming the NCI Radiation Risk Assessment Tool (RadRAT) for estimating the lifetime risk of cancer incidence for members of the U.S. population and other selected countries from exposure to ionizing radiation.
Mr. Thomas provided the primary programming efforts for two independent web-based versions of the Interactive RadioEpidemiological Program (IREP), one for the National Cancer Institute (NCI) and one for the National Institute of Occupational Safety and Health (NIOSH). Both versions of IREP are available online (NIH-IREP and NIOSH-IREP). The NIOSH version of IREP is currently being used by NIOSH and Department of Labor for adjudicating claims of sick nuclear workers. He prepared user’s guides for these computer programs and trained DOL claims examiners in the use of IREP.
Mr. Thomas contributed to the development of an internet-based computer code to support NCI’s efforts in disseminating quantitative information about the thyroid dose and future lifetime risk of thyroid cancer incidence from exposure to radionuclides in fallout following atmospheric nuclear bomb tests at the Nevada test site and other global sites (Fallout Calculator).
In collaboration with the University of Utah, he created a special version of the NCI Fallout Calculator that runs in batch mode for estimation of thyroid doses and risks of thyroid cancer for an individual born in a given year (birth cohort) and living in the same U.S. county for their lifetime. He generated sets of results for store bought cow’s milk (for males and females) and for backyard cow milk (for males and females). All results have been stored in a database with a user interface allowing online access at the following link: http://fallout.orrisk.com/fallout.
Mr. Thomas supported the University of Utah in the reconstruction of models and assumptions used to calculate individual thyroid doses in the "Cohort Study of Thyroid Disease and Radioactive Fallout from the Nevada Test Site." He reprogrammed the entire suite of calculations, based on the intent of the authors of the study. The assumptions used in the original study to identify uncertainty shared among individual members of the cohort, as well as the uncertainty unique to each individual, were reevaluated. Through these efforts, he provided recommendations to upgrade and improve existing models and assumptions to more realistically account for uncertainty. This updated information was used to re-evaluate the association between exposure to I-131 and thyroid cancer.
E-mail Mr. Thomas at: brian@orrisk.com
