Wavelength Optimization for Quantitative Spectral Imaging of Breast Tumor Margins

Abstract

A wavelength selection method that combines an inverse Monte Carlo model of reflectance and a genetic algorithm for global optimization was developed for the application of spectral imaging of breast tumor margins. The selection of wavelengths impacts system design in cost, size, and accuracy of tissue quantitation. The minimum number of wavelengths required for the accurate quantitation of tissue optical properties is 8, with diminishing gains for additional wavelengths. The resulting wavelength choices for the specific probe geometry used for the breast tumor margin spectral imaging application were tested in an independent pathology-confirmed ex vivo breast tissue data set and in tissue-mimicking phantoms. In breast tissue, the optical endpoints (hemoglobin, β-carotene, and scattering) that provide the contrast between normal and malignant tissue specimens are extracted with the optimized 8-wavelength set with <9% error compared to the full spectrum (450–600 nm). A multi-absorber liquid phantom study was also performed to show the improved extraction accuracy with optimization and without optimization. This technique for selecting wavelengths can be used for designing spectral imaging systems for other clinical applications.

Optimal wavelength combinations for near-infrared spectroscopic monitoring of changes in brain tissue hemoglobin and cytochrome c oxidase concentrations

“…Various strategies have recently been proposed to identify optimal wavelength combinations for analysis of different tissue sites using NIRS or other optical modalities. These include adoption of analytical or model-driven performance metrics to minimize chromophore cross-talk and to maximize separability [22][23][24][25][26][27][28][29], recursive elimination of extraneous wavelengths [30], and implementation of GA-based search routines that can be applied to experimental, clinical, or model-generated data [31]. Our group has collected a significant amount of cerebral NIRS measurements from newborn piglets over the past several years; this has motivated us to implement a GA-based routine and to perform a heuristic search for wavelength combinations that can provide accurate information on HI-induced changes in cerebral chromophore concentrations.…”

Length-free near infrared measurement of newborn malnutrition

“…The selection of wavelengths was still referred to absorption peaks of water and fat. The increases of R which resulted from increasing the number of wavelength ratios used agrees with a study of breast imaging by Lo et al ., which they found that adding more wavelengths up to eight improved extraction errors24. Although the R continues to increase with the number of wavelength ratios used, the increase is leveling off and the inclusion of these additional wavelengths would involve more cost in the final device which is intended for use with discrete diodes for low cost.…”

Miniature spectral imaging device for wide-field quantitative functional imaging of the morphological landscape of breast tumor margins

“…Compressive sensing is achieved through optimized bandpass filter center wavelengths (470, 480, 490, 500, 510, 560, 580, and 600 nm) informed by a genetic algorithm analysis of previous clinical data. 11 The lamp, imaging platform, and amplifier system are daisy chained to a universal serial bus (USB) hub within the amplifier box, allowing full system control via a laptop and a single USB connection. The control software was developed using the LabVIEW™G language; an object oriented framework was chosen to maintain scalability and incorporate a hardware abstraction layer.…”