Neutron stimulated emission computed tomography (NSECT) is being developed to noninvasively determine concentrations of
trace elements in
biological tissue. Studies have shown prominent differences in the
trace element concentration of normal and malignant breast tissue. NSECT has the potential to detect these differences and diagnose
malignancy with high accuracy with dose comparable to that of a single mammogram. In this study, NSECT imaging was simulated for normal and malignant human breast tissue samples to determine the significance of individual elements in determining
malignancy. The normal and malignant models were designed with different elemental compositions, and each was scanned spectroscopically using a simulated 2.5 MeV neutron beam. The number of incident neutrons was varied from 0.5 million to 10 million neutrons. The resulting gamma spectra were evaluated through receiver operating characteristic (ROC) analysis to determine which
trace elements were prominent enough to be considered markers for
breast cancer detection. Four elemental
isotopes (133Cs, 81Br, 79Br, and 87Rb) at five energy levels were shown to be promising features for
breast cancer detection with an area under the ROC curve (A(Z)) above 0.85. One of these elements--87Rb at 1338 keV--achieved perfect classification
at 10 million incident neutrons and could be detected with as low as 3 million incident neutrons. Patient dose was calculated for each gamma spectrum obtained and was found to range from between 0.05 and 0.112 mSv depending on the number of neutrons. This simulation demonstrates that NSECT has the potential to noninvasively detect
breast cancer through five prominent
trace element energy levels, at dose levels comparable to other
breast cancer screening techniques.