William Paul Segars
Associate Professor in Radiology
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.
Appointments and Affiliations
- Associate Professor in Radiology
- Office Location: Hock Plaza Suite 302, 2424 Erwin Road, Durham, NC 27705
- Office Phone: (919) 684-1473
- Email Address: firstname.lastname@example.org
- Ph.D. University of North Carolina - Chapel Hill, 2001
Computer-generated phantoms and simulation techniques to investigate and optimize medical imaging systems and methods; development of computational models of patients and imaging devices.
Awards, Honors, and Distinctions
- Farrington Daniels Award. American Association of Physicists in Medicine. 2013
- BME 791: Graduate Independent Study
- BME 792: Continuation of Graduate Independent Study
- Gonzales, MJ; Sturgeon, G; Krishnamurthy, A; Hake, J; Jonas, R; Stark, P; Rappel, W-J; Narayan, SM; Zhang, Y; Segars, WP; McCulloch, AD, A three-dimensional finite element model of human atrial anatomy: new methods for cubic Hermite meshes with extraordinary vertices., Med Image Anal, vol 17 no. 5 (2013), pp. 525-537 [10.1016/j.media.2013.03.005] [abs].
- Hsu, CML; Palmeri, ML; Segars, WP; Veress, AI; Dobbins, JT, Generation of a suite of 3D computer-generated breast phantoms from a limited set of human subject data., Med Phys, vol 40 no. 4 (2013) [10.1118/1.4794924] [abs].
- Segars, WP; Bond, J; Frush, J; Hon, S; Eckersley, C; Williams, CH; Feng, J; Tward, DJ; Ratnanather, JT; Miller, MI; Frush, D; Samei, E, Population of anatomically variable 4D XCAT adult phantoms for imaging research and optimization., Med Phys, vol 40 no. 4 (2013) [10.1118/1.4794178] [abs].
- Li, X; Samei, E; Williams, CH; Segars, WP; Tward, DJ; Miller, MI; Ratnanather, JT; Paulson, EK; Frush, DP, Effects of protocol and obesity on dose conversion factors in adult body CT., Medical Physics, vol 39 no. 11 (2012), pp. 6550-6571 [10.1118/1.4754584] [abs].
- Zhang, Y; Li, X; Segars, WP; Samei, E, Organ doses, effective doses, and risk indices in adult CT: comparison of four types of reference phantoms across different examination protocols., Medical Physics, vol 39 no. 6 (2012), pp. 3404-3423 [10.1118/1.4718710] [abs].
- Hsu, CML; Palmeri, ML; Segars, WP; Veress, AI; Dobbins, JT, An analysis of the mechanical parameters used for finite element compression of a high-resolution 3D breast phantom., Medical Physics, vol 38 no. 10 (2011), pp. 5756-5770 [10.1118/1.3637500] [abs].
- Veress, AI; Segars, WP; Tsui, BMW; Gullberg, GT, Incorporation of a left ventricle finite element model defining infarction into the XCAT imaging phantom., Ieee Trans Med Imaging, vol 30 no. 4 (2011), pp. 915-927 [10.1109/TMI.2010.2089801] [abs].
- Li, X; Samei, E; Segars, WP; Sturgeon, GM; Colsher, JG; Toncheva, G; Yoshizumi, TT; Frush, DP, Patient-specific radiation dose and cancer risk estimation in CT: part II. Application to patients., Medical Physics, vol 38 no. 1 (2011), pp. 408-419 [10.1118/1.3515864] [abs].
- Li, X; Samei, E; Segars, WP; Sturgeon, GM; Colsher, JG; Toncheva, G; Yoshizumi, TT; Frush, DP, Patient-specific radiation dose and cancer risk estimation in CT: part I. development and validation of a Monte Carlo program., Medical Physics, vol 38 no. 1 (2011), pp. 397-407 [10.1118/1.3515839] [abs].
- Tward, DJ; Ceritoglu, C; Kolasny, A; Sturgeon, GM; Segars, WP; Miller, MI; Ratnanather, JT, Patient Specific Dosimetry Phantoms Using Multichannel LDDMM of the Whole Body., Int J Biomed Imaging, vol 2011 (2011) [10.1155/2011/481064] [abs].
- Segars, WP; Sturgeon, G; Mendonca, S; Grimes, J; Tsui, BMW, 4D XCAT phantom for multimodality imaging research., Med Phys, vol 37 no. 9 (2010), pp. 4902-4915 [10.1118/1.3480985] [abs].