Near Infrared Imaging of Tissue Heterogeneity: Probe Design and Sensitivity Analysis

Abstract

A CW type handheld near infrared tissue oximeter called P-Scan tissue imager was developed for real time imaging of tissue oxygen saturation ([StO2]) and hemoglobin concentration ([Hbt]). The probe consists of eight dual-wavelength light sources (690nm and 830nm) and eight photon detectors forming a 2.5cm X 2.5cm matrix. The local tissue oxygen saturation and hemoglobin concentration was calculated based on optical measurement of absorption coefficients for oxy and deoxy hemoglobin. A superimposition algorithm was developed for direct imaging of local tissue [StO2]/[Hbt] without complex inverse reconstruction. The measurement sensitivity of such a P-Scan device with respect to tumor size, tumor depth, tumor lateral location and tumor optical contrast was studied. First order Born approximation was used to simulate the photon migration in a 2D turbid model with an embedded absorber. The simulation results implied that the P-Scan imager is able to detect the tissue heterogeneity up to 1.5 cm deep with reasonably high sensitivity. Simulation also indicated that among multiple factors that may influence the P-Scan sensitivity, tumor size and tumor depth are dominant factors.^*

US-guided diffused optical tomography: a promising functional imaging technique in breast lesions

“…The reconstruction process used the Born approximation to relate the scattered field measured at the probe surface to absorption variations in each volume element within the tissue [10]. The scattered field that was used for optical imaging reconstruction was calculated as the difference between measurements obtained at the lesion site and those obtained at the reference site.…”

Hand-held based near-infrared optical imaging devices: A review

“…Parallelly, a different CW-based device (Device #7, Table 1) was developed by another research group at the University of Pennsylvania [51,62], employing a long coherence laser source (four sources) and fast photon-counting avalanche photodiodes as detectors (four of them) coupled via detector fibers. In contrast, a hand-held device (termed as a tissue oximeter) developed at the Ohio State University (Device #6, Table 1) contained embedded laser diode and photodiode modules for CW-based NIR imaging [48,49,64].…”

“…• A breast imaging device developed at Ohio State University and ViOptix, Inc. (Device #6a, Fig. 2) contained eight sources and eight detectors arranged in a 2.5 cm × 2.5 cm matrix [48,49] in order to image even larger areas. A second generation of the device was later developed (Device #6b, Table 1) that contained 16 sources and 8 detectors to form a 3 cm × 3 cm matrix [50].…”

Clinical Translation of a Novel Hand-held Optical Imager for Breast Cancer Diagnosis

“…Simulation experiments and sensitivity analysis were performed with respect to tumor size, tumor depth, tumor lateral location, and optical contrast [55]. The maximum measurement depth was 1.5 cm with absorption sensitivity of 0.1 cm.…”

“…� The hand-held device (termed as tissue oximeter by the researchers) designed by Xu, et al (Device #6, Table 3.1) was used for real time imaging of tissue oxygen saturation and hemoglobin concentrations [55][56][57]. Simulation experiments and sensitivity analysis were performed with respect to tumor size, tumor depth, tumor lateral location, and optical contrast [55].…”