CSRI Seminar: Ariela Sofer

Title	Optimization in Medical Diagnosis
Speaker E-mail From	Ariela Sofer asofer@gmu.edu George Mason University
Date Time Location	Tuesday, June 5, 2001 10-11am (PST) Bldg. 940, Auditorium (Sandia - CA) Bldg. 980, Room 24 (Sandia - NM)
Abstract	In the past few years optimization has emerged as a promising tool in solving problems in medical diagnosis and treatment. This talk discusses the application of optimization to two problems in medical diagnosis: image reconstruction in positron emission tomography (PET), and biopsy protocols for diagnosis of prostate cancer. (PET) is a medical imaging technique used for studying blood flow and metabolism of an organ. PET is used in studying brain function, and in diagnosing Alzheimers's disease and certain forms of cancer. Maximum likelihood reconstructions of PET images often have improved resolution over nonstatistical reconstructions, yet they are generally considered to be too expensive. This talk investigates the solution of 3-D maximum likelihood reconstruction problems via a primal-dual interior point method. The algorithm uses an early-terminated conjugate gradient to obtain an approximate Newton direction. We discuss a variety of computational issues such as data structures, preconditioning techniques, scaling of variables and the line search,and present computational results on problems involving over a million variables. This research is joint with Calvin Johnson, NIH. Prostate needle biopsy is used for the detection of prostate cancer. The protocol of needle biopsy most commonly used in the clinical environment is a an empirical technique which defines six symmetric locations on the prostate surface for needle insertion. Recent studies, however, have shown that a significant number of patients are not diagnosed at their first biopsy. We develop an alternative optimized biopsy protocol based on a 3-D distribution map of prostate cancer. This research is joint with Jianchao Zeng and Brett Opell, Georgetown University Medical Center.
About the Speaker	Ariela Sofer is a Professor in the Systems Engineering and Operations Research Department at George Mason University. She is an expert on Nonlinear Programming, Numerical Analysis, and Software Reliability. She has co-authored two books and written several papers.

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