TITLE: Simulations to Evaluate Accuracy and Patient Dose in Neutron-Stimulated, Emission-Computed Tomography (NSECT) for Diagnosis of Breast Cancer PRINCIPAL INVESTIGATOR:

Neutron stimulated emission computed tomography (NSECT) is being developed as a non-invasive spectroscopic technique to determine element concentrations in the human body. We have implemented an NSECT system that uses a beam of high-energy neutrons to identify element concentrations in tissue and create 2-dimensional maps of elemental distribution through a single non-invasive tomographic scan. Neutrons scatter inelastically with atomic nuclei in tissue, causing them to emit characteristic gamma photons. These gamma photons are detected and identified using an energy-sensitive gamma detector. By measuring the energy and number of emitted gamma photons, the system can determine the elemental composition of the target tissue. NSECT has the advantage of being able to detect breast cancer at very early stages compared to anatomic screening techniques, as it detects changes in trace element concentrations in the breast, which usually occur before anatomical features such as tumors and micro-calcifications appear. The tomographic scanning system eliminates the need for breast compression and patient disrobing. The system design can be made portable by using a commercially available portable neutron source with a gamma detector. From our preliminary results, NSECT shows significant promise in early diagnosis of breast cancer. It has the potential to evolve into an easily accessible screening modality and diagnostic technique for breast Manuscript received November 13, 2006. This work was supported by the NIH/NCI grant 1-R21-CA106873-01 and in part by Department of Defense (Breast Cancer Research Program) under award number W81XWH-06-10484. A. J. Kapadia is with the Department of Biomedical Engineering and the Duke Advanced Imaging Laboratories (DAILabs) of the Department of Radiology, Duke University, Durham, NC 27710, USA (phone: 919-6841470; fax: 919-684-1491; email: [email protected]). A.C. Sharma is with the Department of Biomedical Engineering and the DAILabs of the Department of Radiology, Duke University, Durham, NC 27710, USA (phone: 919-684-1471; fax: 919-684-1491; email: [email protected]). G.D. Tourassi is with the DAILabs of the Department of Radiology, Duke University, Durham, NC 27710, USA (phone: 919-684-1447; fax: 919-6841491; email: [email protected]). J. E. Bender is with the Department of Biomedical Engineering, Duke University, Durham, NC 27710, USA (email: [email protected]). A. S. Crowell is with the Department of Physics, Duke University and the Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA (phone: 919-660-2639; fax: 919-660-2634; email: [email protected]). M. R. Kiser is with the Department of Physics, Duke University and the Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA (phone: 919-660-2639; fax: 919-660-2634; email: [email protected]). C. R. Howell is with the Department of Physics, Duke University and the Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA (phone: 919-660-2632; fax: 919-660-2634; email: [email protected]). C. E. Floyd Jr. is with the DAILabs of the Department of Radiology, Duke University Medical Center and the Department of Biomedical Engineering Duke University, Durham, NC 27710. cancer, which can detect and identify malignant tissue in the breast and generate a two-dimensional image through a single non-invasive tomographic scan. Patient dose levels from NSECT are comparable to those of screening mammography. Efforts are under way to achieve the micro-gram sensitivity required for invivo trace element detection in the breast at the lowest possible patient dose levels. Our final goal is to implement a portable, low-dose tomographic screening system for breast cancer which does not require breast compression or invasive biopsies.