W Paul Segars, PhD

Associate Professor in Radiology
Address: Box 2731 Med Ctr, 2424 Erwin Road
Durham, NC 27710
Phone: (919) 684-1473
Email: paul.segars@duke.edu

Research Interests

Our current research involves the use of computer-generated phantoms and simulation techniques to investigate and optimize medical imaging systems and methods. Medical imaging simulation involves virtual experiments carried out entirely on the computer using computational models for the patients as well as the imaging devices. Simulation is a powerful tool for characterizing, evaluating, and optimizing medical imaging systems. A vital aspect of simulation is to have realistic models of the subject's anatomy as well as accurate models for the physics of the imaging process. Without this, the results of the simulation may not be indicative of what would occur in actual clinical studies and would, therefore, have limited practical value. We are leading the development of realistic simulation tools for use toward human and small animal imaging research.

These tools have a wide variety of applications in many different imaging modalities to investigate the effects of anatomical, physiological, physical, and instrumentational factors on medical imaging and to research new image acquisition strategies, image processing and reconstruction methods, and image visualization and interpretation techniques. We are currently applying them to the field of x-ray CT. The motivation for this work is the lack of sufficiently rigorous methods for optimizing the image quality and radiation dose in x-ray CT to the clinical needs of a given procedure. The danger of unnecessary radiation exposure from CT applications, especially for pediatrics, is just now being addressed. Optimization is essential in order for new and emerging CT applications to be truly useful and not represent a danger to the patient. Given the relatively high radiation doses required of current CT systems, thorough optimization is unlikely to ever be done in live patients. It would be prohibitively expensive to fabricate physical phantoms to simulate a realistic range of patient sizes and clinical needs especially when physiologic motion needs to be considered. The only practical approach to the optimization problem is through the use of realistic computer simulation tools developed in our work.


Sugiura, Teruyo, et al. “Quantitative analysis of changes in lung density by dynamic chest radiography in association with CT values: a virtual imaging study and initial clinical corroboration.Radiol Phys Technol, vol. 15, no. 1, Mar. 2022, pp. 45–53. Pubmed, doi:10.1007/s12194-021-00648-w.

Sharma, Shobhit, et al. “A GPU-accelerated framework for individualized estimation of organ doses in digital tomosynthesis.Med Phys, vol. 49, no. 2, Feb. 2022, pp. 891–900. Pubmed, doi:10.1002/mp.15400.

Fu, Wanyi, et al. “Corrections to "iPhantom: A Framework for Automated Creation of Individualized Computational Phantoms and its Application to CT Organ Dosimetry".Ieee J Biomed Health Inform, vol. 26, no. 1, Jan. 2022, p. 478. Pubmed, doi:10.1109/JBHI.2021.3130397.

Fricks, Rafael B., et al. “Deep learning classification of COVID-19 in chest radiographs: performance and influence of supplemental training.J Med Imaging (Bellingham), vol. 8, no. 6, Nov. 2021, p. 064501. Pubmed, doi:10.1117/1.JMI.8.6.064501.

Ria, Francesco, et al. “Correction to: Comparison of 12 surrogates to characterize CT radiation risk across a clinical population.Eur Radiol, vol. 31, no. 10, Oct. 2021, p. 8068. Pubmed, doi:10.1007/s00330-021-07903-z.

Jadick, Giavanna, et al. “A scanner-specific framework for simulating CT images with tube current modulation.Phys Med Biol, vol. 66, no. 18, Sept. 2021. Pubmed, doi:10.1088/1361-6560/ac2269.

Ria, Francesco, et al. “Comparison of 12 surrogates to characterize CT radiation risk across a clinical population.Eur Radiol, vol. 31, no. 9, Sept. 2021, pp. 7022–30. Pubmed, doi:10.1007/s00330-021-07753-9.

Fu, Wanyi, et al. “iPhantom: A Framework for Automated Creation of Individualized Computational Phantoms and Its Application to CT Organ Dosimetry.Ieee J Biomed Health Inform, vol. 25, no. 8, Aug. 2021, pp. 3061–72. Pubmed, doi:10.1109/JBHI.2021.3063080.