W Paul Segars, PhD

Associate Professor in Radiology
Department: Radiology
Division: Radiology - General
Address: Hock Plaza Suite 302
2424 Erwin Road
Durham, NC 27705
Office Phone: (919) 684-1473
Email: paul.segars@duke.edu
Web: http://railabs.duhs.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.

Publications

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. 2013;40:043701. Abstract

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. 2013;40:043703. Abstract

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. Medical Image Analysis. 2013;17:525-537. Abstract

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. 2012;39:6550-6571. Abstract

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. 2012;39:3404-3423. Abstract

Veress, AI; Segars, WP; Tsui, BMW; Gullberg, GT. Incorporation of a left ventricle finite element model defining infarction into the XCAT imaging phantom. IEEE Transactions on Medical Imaging. 2011;30:915-927. Abstract

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. 2011;38:397-407. Abstract

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. International Journal of Biomedical Imaging. 2011;2011:481064. Abstract

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. 2011;38:408-419. Abstract

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. 2011;38:5756-5770. Abstract

Segars, WP; Sturgeon, G; Mendonca, S; Grimes, J; Tsui, BMW. 4D XCAT phantom for multimodality imaging research. Medical physics. 2010;37:4902-4915. Abstract