An advanced hyper-spectral imaging (HSI) system has been developed for use in medical diagnostics. One such diagnostic, esophageal cancer is diagnosed currently through biopsy and subsequent pathology. The end goal of this research is to develop an optical-based technique to assist or replace biopsy. In this paper, we demonstrate an instrument that has the capability to optically diagnose cancer in laboratory mice. We have developed a real-time HSI
system based on state-of-the-art liquid crystal tunable filter (LCTF) technology coupled to an endoscope. This unique HSI technology is being developed to obtain spatially resolved images of the slight differences in luminescent properties of normal versus tumorous tissues. In this report, an in-vivo mouse study is shown. A predictive measure of cancer for the mice studied is developed and shown. It is hoped that the results of this study will lead to advances in the optical diagnosis of esophageal cancer in humans.
This paper describes the development of a compact, self-contained, and portable Raman Integrated Tunable Sensor (RAMiTS) for chemical and biosensing. The RAMiTS consists of a frequency-stabilized diode laser for excitation, an acousto-optic tunable filter (AOTF) for wavelength discrimination, and an avalanche photodiode (APD) for detection. It can provide direct identification and quantitative analysis of chemical and biological samples in a few seconds under field conditions. Instrument control and data acquisition was coordinated by software developed in house using the C language. Evaluation of this instrument was performed by analyzing several model compounds and the high spectral resolution of this instrument was demonstrated by the discrimination of several structurally similar molecules (benzene, toluene and naphthalene) as well as m-, o-, p- isomers of xylene. The potential applications of the RAMiTS coupled with the surface-enhanced Raman scattering (SERS) for the detection of chemical and biological warfare agents will also be discussed in this paper.
This paper presents hyperspectral fluorescence imaging and a support vector machine for detecting skin tumors. Skin cancers may not be visually obvious since the visual signature appears as shape distortion rather than discoloration. As a definitive test for cancer diagnosis, skin biopsy requires both trained professionals and significant waiting time. Hyperspectral fluorescence imaging offers an instant, non-invasive diagnostic procedure based on the analysis of the spectral signatures of skin tissue. A hyperspectral image contains spatial information measured at a sequence of individual wavelength across a sufficiently broad spectral band at high-resolution spectrum. Fluorescence is a phenomenon where light is absorbed at a given wavelength and then is normally followed by the emission of light at a longer wavelength. Fluorescence generated by the skin tissue is collected and analyzed to determine whether cancer exists. Oak Ridge National Laboratory developed an endoscopic hyperspectral imaging system capable of fluorescence imaging for skin cancer detection. This hyperspectral imaging system captures hyperspectral images of 21 spectral bands of wavelength ranging from 440 nm to 640 nm. Each band image is spatially co-registered to eliminate the spectral offset caused during the image capture procedure. Image smoothing by means of a local spatial filter with Gaussian kernel increases the classification accuracy and reduces false positives. Experiments show that the SVM classification with spatial filtering achieves high skin tumor detection accuracies.
This paper describes a compact, self-contained, cost effective, and portable Raman Integrated Tunable Sensor (RAMiTs) for screening a wide variety of chemical and biological agents for homeland defense applications. The instrument is a fully-integrated, tunable, "point-and-shoot" Raman monitor based on solid-state acousto-optic tunable filter (AOTF) technology. It can provide direct identification and quantitative analysis of chemical and biological samples in a few seconds under field conditions. It also consists of a 830-nm diode laser for excitation, and an avalanche photodiode for detection. Evaluation of this instrument has been performed by analyzing several standard samples and comparing the results those obtained using a conventional Raman system. In addition to system evaluation, this paper will also discuss potential applications of the RAMiTs for detection of chemical and biological warfare agents.
We present the principles and applications of our dual-modality fluorescence and reflectance hyperspectral imaging (DMHSI) system. In this paper we report on background work done using laser induced fluorescence (LIF) by the group in the early detection of esophageal cancer. We then demonstrate the capabilities of our new DMHSI system. The system consists of a laser, endoscope, AOTF, and two cameras coupled with optics and electronics. Preliminary results, performed on mouse tissue, show that the system can delineate normal and malignant tissue regions in real-time.
An integrated multi-functional biochip based on integrated circuit complementary metal oxide semiconductor (CMOS) sensor array for use in medical diagnostics and pathogen detection has been described. The usefulness and potential of the biochip as a rapid, inexpensive screening tool for detection of bioenvironmental pathogens will be demonstrated. Detection of aerosolized spores was achieved by coupling the miniature system to a portable bioaerosol sampler, and the performance of the antibody-based recognition and enzyme amplification method was evaluated. The bioassay performance was found to be compatible with the air sampling device, and the enzymatic amplification was found to be an attractive amplification method for detection of low spore concentrations. The combined portable bioaerosol sampler and miniature biochip system detected 100 B. globigii spores, corresponding to 17 aerosolized spores/L of air.
This paper describes a self-contained, portable Raman instrument that has been developed for environmental and homeland defense applications. The instrument consists of a 830-nm diode laser for excitation, an acousto-optic tunable filter (AOTF) for wavelength discrimination, and an avalanche photodiode for detection. The primary component of this system is the AOTF and it has been selected based on its spectral range along with its high resolution, ~7.5 cm-1. Software has been developed in house using C programming language for controlling the instrument (i.e. the AOTF frequency, the signal acquisition, etc.). Evaluation of this instrument has been performed by analyzing several standard samples and comparing to a conventional Raman system. In addition to system evaluation, this paper will also discuss potential applications of this instrument to trace detection of hazardous chemicals using the Raman Integrated Tunable Sensor (RAMiTs) coupled with surface-enhance Raman scattering process.