Optical Detection of Tumors In Vivo by Visible Light Tissue Oximetry

2005 ◽  
Vol 4 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Peter G. Maxim ◽  
Jeffrey J. L. Carson ◽  
David A. Benaron ◽  
Billy W. Loo ◽  
Lei Xing ◽  
...  
Keyword(s):  
Visible Light ◽  
Real Time ◽  
Normal Tissue ◽  
Tissue Oxygenation ◽  
Human Subjects ◽  
Standard Procedure ◽  
Human Tumor ◽  
Tumor Oxygenation ◽  
Local Ischemia ◽  
Tissue Oximetry

Endoscopy is a standard procedure for identifying tumors in patients suspected of having gastrointestinal (G.I.) cancer. The early detection of G.I. neoplasms during endoscopy is currently made by a subjective visual inspection that relies to a high degree on the experience of the examiner. This process can be difficult and unreliable, as tumor lesions may be visually indistinguishable from benign inflammatory conditions and the surrounding mucosa. In this study, we evaluated the ability of local ischemia detection using visible light spectroscopy (VLS) to differentiate neoplastic from normal tissue based on capillary tissue oxygenation during endoscopy. Real-time data were collected (i) from human subjects (N=34) monitored at various sites during endoscopy (enteric mucosa, malignant, and abnormal tissue such as polyps) and (ii) murine animal subjects with human tumor xenografts. Tissue oximetry in human subjects during endoscopy revealed a tissue oxygenation (StO2%, mean ± SD) of 46 ± 22% in tumors, which was significantly lower than for normal mucosal oxygenation (72 ± 4%; P ≤ 0.0001). No difference in tissue oxygenation was observed between normal and non-tumor abnormal tissues ( P = N.S.). Similarly, VLS tissue oximetry for murine tumors revealed a mean local tumor oxygenation of 45% in LNCaP, 50% in M21, and 24% in SCCVII tumors, all significantly lower than normal muscle tissue (74%, P < 0.001). These results were further substantiated by positive controls, where a rapid real-time drop in tumor oxygenation was measured during local ischemia induced by clamping or epinephrine. We conclude that VLS tissue oximetry can distinguish neoplastic tissue from normal tissue with a high specificity (though a low sensitivity), potentially aiding the endoscopic detection of gastrointestinal tumors.

scholarly journals Wireless, battery-free optoelectronic systems as subdermal implants for local tissue oximetry

2019 ◽  
Vol 5 (3) ◽  
pp. eaaw0873 ◽  
Author(s):  
Hao Zhang ◽  
Philipp Gutruf ◽  
Kathleen Meacham ◽  
Michael C. Montana ◽  
Xingyue Zhao ◽  
...  
Keyword(s):  
Animal Models ◽  
Tissue Oxygenation ◽  
Human Subjects ◽  
Brain Regions ◽  
Disease States ◽  
Data Output ◽  
Subdermal Implants ◽  
Underlying Mechanisms ◽  
Tissue Oximetry

Monitoring regional tissue oxygenation in animal models and potentially in human subjects can yield insights into the underlying mechanisms of local O2-mediated physiological processes and provide diagnostic and therapeutic guidance for relevant disease states. Existing technologies for tissue oxygenation assessments involve some combination of disadvantages in requirements for physical tethers, anesthetics, and special apparatus, often with confounding effects on the natural behaviors of test subjects. This work introduces an entirely wireless and fully implantable platform incorporating (i) microscale optoelectronics for continuous sensing of local hemoglobin dynamics and (ii) advanced designs in continuous, wireless power delivery and data output for tether-free operation. These features support in vivo, highly localized tissue oximetry at sites of interest, including deep brain regions of mice, on untethered, awake animal models. The results create many opportunities for studying various O2-mediated processes in naturally behaving subjects, with implications in biomedical research and clinical practice.

Real-Time Identification and Tracking of Infrared Markers Based on Kalman Filter

2012 ◽  
Vol 249-250 ◽  
pp. 1147-1153
Author(s):  
Qiao Na Xing ◽  
Da Yuan Yan ◽  
Xiao Ming Hu ◽  
Jun Qin Lin ◽  
Bo Yang
Keyword(s):  
Kalman Filter ◽  
Visible Light ◽  
Real Time ◽  
Complex Terrain ◽  
Experimental Results ◽  
Identification Method ◽  
In The Wild ◽  
Real Time Identification

Automatic equipmenttransportation in the wild complex terrain circumstances is very important in rescue or military. In this paper, an accompanying system based on the identification and tracking of infrared LEDmarkers is proposed. This system avoidsthe defect that visible-light identification method has. In addition, this paper presents a Kalman filter to predict where infraredmarkers may appear in the nextframe imageto reduce the searchingarea of infrared markers, which remarkablyimproves the identificationspeed of infrared markers. The experimental results show that the algorithm proposed in this paper is effective and feasible.

scholarly journals Digital dynamic discrimination of primary colorectal cancer using systemic indocyanine green with near-infrared endoscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeffrey Dalli ◽  
Eamon Loughman ◽  
Niall Hardy ◽  
Anwesha Sarkar ◽  
Mohammad Faraz Khan ◽  
...  
Keyword(s):  
Indocyanine Green ◽  
Real Time ◽  
Normal Tissue ◽  
Near Infrared ◽  
Malignant Lesion ◽  
Fluorescence Analysis ◽  
Video Tracking ◽  
Continuous Stream ◽  
Rich Data

AbstractAs indocyanine green (ICG) with near-infrared (NIR) endoscopy enhances real-time intraoperative tissue microperfusion appreciation, it may also dynamically reveal neoplasia distinctively from normal tissue especially with video software fluorescence analysis. Colorectal tumours of patients were imaged mucosally following ICG administration (0.25 mg/kg i.v.) using an endo-laparoscopic NIR system (PINPOINT Endoscopic Fluorescence System, Stryker) including immediate, continuous in situ visualization of rectal lesions transanally for up to 20 min. Spot and dynamic temporal fluorescence intensities (FI) were quantified using ImageJ (including videos at one frame/second, fps) and by a bespoke MATLAB® application that provided digitalized video tracking and signal logging at 30fps (Fluorescence Tracker App downloadable via MATLAB® file exchange). Statistical analysis of FI-time plots compared tumours (benign and malignant) against control during FI curve rise, peak and decline from apex. Early kinetic FI signal measurement delineated discriminative temporal signatures from tumours (n = 20, 9 cancers) offering rich data for analysis versus delayed spot measurement (n = 10 cancers). Malignant lesion dynamic curves peaked significantly later with a shallower gradient than normal tissue while benign lesions showed significantly greater and faster intensity drop from apex versus cancer. Automated tracker quantification efficiently expanded manual results and provided algorithmic KNN clustering. Photobleaching appeared clinically irrelevant. Analysis of a continuous stream of intraoperatively acquired early ICG fluorescence data can act as an in situ tumour-identifier with greater detail than later snapshot observation alone. Software quantification of such kinetic signatures may distinguish invasive from non-invasive neoplasia with potential for real-time in silico diagnosis.

scholarly journals Measurement of renal tissue oxygenation with blood oxygen level-dependent MRI and oxygen transit modeling

2014 ◽  
Vol 306 (6) ◽  
pp. F579-F587 ◽  
Author(s):  
Jeff L. Zhang ◽  
Glen Morrell ◽  
Henry Rusinek ◽  
Lizette Warner ◽  
Pierre-Hugues Vivier ◽  
...  
Keyword(s):  
Tissue Oxygenation ◽  
Human Subjects ◽  
Blood Oxygen Level Dependent ◽  
Renal Tissue ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level ◽  
Healthy Human ◽  
Bold Mri ◽  
Before And After

Blood oxygen level-dependent (BOLD) MRI data of kidney, while indicative of tissue oxygenation level (Po2), is in fact influenced by multiple confounding factors, such as R2, perfusion, oxygen permeability, and hematocrit. We aim to explore the feasibility of extracting tissue Po2 from renal BOLD data. A method of two steps was proposed: first, a Monte Carlo simulation to estimate blood oxygen saturation (SHb) from BOLD signals, and second, an oxygen transit model to convert SHb to tissue Po2. The proposed method was calibrated and validated with 20 pigs (12 before and after furosemide injection) in which BOLD-derived tissue Po2 was compared with microprobe-measured values. The method was then applied to nine healthy human subjects (age: 25.7 ± 3.0 yr) in whom BOLD was performed before and after furosemide. For the 12 pigs before furosemide injection, the proposed model estimated renal tissue Po2 with errors of 2.3 ± 5.2 mmHg (5.8 ± 13.4%) in cortex and −0.1 ± 4.5 mmHg (1.7 ± 18.1%) in medulla, compared with microprobe measurements. After injection of furosemide, the estimation errors were 6.9 ± 3.9 mmHg (14.2 ± 8.4%) for cortex and 2.6 ± 4.0 mmHg (7.7 ± 11.5%) for medulla. In the human subjects, BOLD-derived medullary Po2 increased from 16.0 ± 4.9 mmHg (SHb: 31 ± 11%) at baseline to 26.2 ± 3.1 mmHg (SHb: 53 ± 6%) at 5 min after furosemide injection, while cortical Po2 did not change significantly at ∼58 mmHg (SHb: 92 ± 1%). Our proposed method, validated with a porcine model, appears promising for estimating tissue Po2 from renal BOLD MRI data in human subjects.

Real-time Demonstration of 5G MMW Beamforming and Tracking Using Integrated Visible Light Positioning System

2021 ◽  
Author(s):  
Chin-Wei Hsu ◽  
Shang-Jen Su ◽  
You-Wei Chen ◽  
Qi Zhou ◽  
Yahya Alfadhli ◽  
...  
Keyword(s):  
Visible Light ◽  
Real Time ◽  
Positioning System
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