Optical mammography combined with fluorescence imaging: lesion detection using scatterplots.

Using scatterplots of 2 or 3 parameters, diffuse optical tomography and fluorescence imaging are combined to improve detectability of breast lesions. Small or low contrast phantom-lesions that were missed in the optical and fluorescence images were detected in the scatterplots. In patient measurements, all tumors were visible and easily differentiated from artifacts and areolas in the scatterplots. The different rate of intake and wash out of the fluorescent contrast agent in the healthy versus malignant tissues was also observed in the scatterplot: this information can be used to discriminate malignant lesion from normal structures.

Diffuse optical tomography of the breast: preliminary findings of a new prototype and comparison with magnetic resonance imaging.

This paper presents an evaluation of a prototype diffuse optical tomography (DOT) system. Seventeen women with 18 breast lesions (10 invasive carcinomas, 2 fibroadenomas, and 6 benign cysts; diameters 13-54 mm) were evaluated with DOT and magnetic resonance imaging (MRI). A substantial fraction of the original 36 recruited patients could not be examined using this prototype due to technical problems. A region of interest (ROI) was drawn at the lesion position as derived from MRI and at the mirror image site in the contralateral healthy breast. ROIs were assessed quantitatively and qualitatively by two observers independently in two separate readings. Intra- and interobserver agreements were calculated using kappa statistics (k) and intraclass correlation coefficients (ICCs). Discriminatory values for presence of malignancy were determined by receiver operating characteristic (ROC) analyses. Intraobserver agreements were excellent (k 0.88 and 0.88; ICC 0.978 and 0.987), interobserver agreements were good to excellent (k 0.77-0.95; ICC 0.96-0.98). Discriminatory values for presence of malignancy were 0.92-0.93 and 0.97-0.99 for quantitative and qualitative ROC analysis, respectively. This DOT system has the potential to discriminate malignant from benign breast tissue in a reproducible qualitative and quantitative manner. Important technical improvements are required before this technique is ready for clinical application.

Efficient coupling into and out of high-Q resonators.

The temporal-coupled-mode theory is directly applied to the design of devices that feature a resonator with a high quality factor. For the temporal-coupled-mode theory we calculate the decay rate of the resonator to determine the transmission properties of the device. The analysis using the decay rates requires little computational effort, and therefore the optimum device properties can be determined quickly. Two examples, a wavelength filter and a resonator crossing, are presented to illustrate the use of the analysis.