IDEAL-OBSERVER ANALYSIS OF LESION DETECTABILITY IN PLANAR, CONVENTIONAL SPECT, AND DEDICATED SPECT SCINTIMAMMOGRAPHY USING EFFECTIVE MULTIDIMENSIONAL SMOOTHING

Scintimammography, a nuclear-medicine imaging technique that relies on the preferential uptake of Tc-99m-sestamibi and other radionuclides i n breast malignancies, has the potential to provide differentiation of mammographically suspicious lesions, as well as outright detection of malignancies in women with radiographically dense breasts. In this wo rk we use the ideal-observer framework to quantify the detectability o f a 1-cm lesion using three, different imaging geometries: the planar technique that is the current clinical standard, conventional single-p hoton emission computed tomography (SPECT), in which the scintillation cameras rotate around the entire torso, and dedicated breast SPECT, i n which the cameras rotate around the breast alone. We also introduce an adaptive smoothing technique for the processing of planar images an d of sinograms that exploits Fourier transforms to achieve effective m ultidimensional smoothing at a reasonable computational cost. For the detection of a 1-cm lesion with a clinically typical 6:1 tumor-backgro und ratio, we find ideal-observer signal-to-noise ratios (SNR) that su ggest that the dedicated breast SPECT geometry is the most effective o f the three, and that the adaptive, two-dimensional smoothing techniqu e should enhance lesion detectability in the tomographic reconstructio ns.