A digital x-ray tomosynthesis coupled near infrared spectral tomography system for dual-modality breast imaging

Abstract

A Near Infrared Spectral Tomography (NIRST) system has been developed and integrated into a commercial Digital Breast Tomosynthesis (DBT) scanner to allow structural and functional imaging of breast in vivo. The NIRST instrument uses an 8-wavelength continuous wave (CW) laserbased scanning source assembly and a 75-element silicon photodiode solidstate detector panel to produce dense spectral and spatial projection data from which spectrally constrained 3D tomographic images of tissue chromophores are produced. Integration of the optical imaging system into the DBT scanner allows direct co-registration of the optical and DBT images, while also facilitating the synergistic use of x-ray contrast as anatomical priors in optical image reconstruction. Currently, the total scan time for a combined NIRST-DBT exam is ~50s with data collection from 8 wavelengths in the optical scan requiring ~42s to complete. The system was tested in breast simulating phantoms constructed using intralipid and blood in an agarose matrix with a 3 cm x 2 cm cylindrical inclusion at 1 cm depth from the surface. Diffuse image reconstruction of total hemoglobin (HbT) concentration resulted in accurate recovery of the lateral size and position of the inclusion to within 6% and 8%, respectively. Use of DBT structural priors in the NIRST reconstruction process improved the quantitative accuracy of the HbT recovery, and led to linear changes in imaged versus actual contrast, underscoring the advantages of dual-modality optical imaging approaches. The quantitative accuracy of the system can be further improved with independent measurements of scattering properties through integration of frequency or time domain data. ©2012 Optical Society of America

Near-infrared spectral tomography integrated with digital breast tomosynthesis: Effects of tissue scattering on optical data acquisition design

“…More information on system performance can be found in concurrent work. 33 An analysis of the effects of scattering error on HbT concentration recovered from the phantom data showed similar results to the patient simulations in Fig. 7.…”

Digital Breast Tomosynthesis: State of the Art

“…Multiple research teams are investigating the combination of DBT with nearinfrared spectroscopy, or NIRS (157)(158)(159)(160). NIRS can estimate hemoglobin concentration and oxygen saturation, which have the potential to discriminate between benign and malignant lesions.…”

Integration of microwave tomography with magnetic resonance for improved breast imaging

“…We have experience at Dartmouth with multimodality combinations involving diffuse light in the near-infrared, termed Near InfraRed Spectral Tomography (NIRST), and have developed platforms with breast x-ray tomosynthesis 51,52 and MR. 53,54 Similar to MT, NIRST alone provides molecular specificity in terms of intrinsic breast tissue composition, but at poor spatial resolution, and when used in combination is significantly advantaged by the high-resolution spatial information provided by traditional breast imaging. The most robust and diagnostically significant NIRST parameter has been total hemoglobin concentration, Hb T , evidently because it is a surrogate for localized vascular density and associated angiogenic activity in cancers.…”