Papers by Robert Nordstrom
Radiology: Imaging Cancer
Tomography, 2020
The June 2020 special issue of Tomography is a collection of articles from over 20 research teams... more The June 2020 special issue of Tomography is a collection of articles from over 20 research teams that are members of the Quantitative Imaging Network (QIN) supported and organized by the National Institutes of Health (NIH).[...]
Tomography, 2016
Precision medicine is a healthcare model that seeks to incorporate a wealth of patient informatio... more Precision medicine is a healthcare model that seeks to incorporate a wealth of patient information to identify and classify disease progression and to provide tailored therapeutic solutions for individual patients. Interventions are based on knowledge of molecular and mechanistic causes, pathogenesis and pathology of disease. Individual characteristics of the patients are then used to select appropriate healthcare options. Imaging is playing an increasingly important role in identifying relevant characteristics that help to stratify patients for different interventions. However, lack of standards, limitations in image-processing interoperability, and errors in data collection can limit the applicability of imaging in clinical decision support. Quantitative imaging is the attempt to extract reliable, numerical information from images to eliminate qualitative judgments and errors for providing accurate measures of tumor response to therapy or for predicting future response. This issue...
Tomography, 2019
The Quantitative Imaging Network of the National Cancer Institute is in its 10th year of operatio... more The Quantitative Imaging Network of the National Cancer Institute is in its 10th year of operation, and research teams within the network are developing and validating clinical decision support software tools to measure or predict the response of cancers to various therapies. As projects progress from development activities to validation of quantitative imaging tools and methods, it is important to evaluate the performance and clinical readiness of the tools before committing them to prospective clinical trials. A variety of tests, including special challenges and tool benchmarking, have been instituted within the network to prepare the quantitative imaging tools for service in clinical trials. This article highlights the benchmarking process and provides a current evaluation of several tools in their transition from development to validation.
The Review of Laser Engineering
Stable and repetitive single-longitudinal-mode output from a pulsed TEA carbon dioxide laser has ... more Stable and repetitive single-longitudinal-mode output from a pulsed TEA carbon dioxide laser has been achieved using a time-gated gain cell. The gain cell is operated as an oscillator for the time periods between the laser pulses. Before the TEA laser is triggered, the gain cell is rapidly switched below threshold to avoid saturation of the gain-switched spike in the TEA laser pulse. Standard dither-stabilization techniques can be used during the CW operation of the gain cell to position the output coupler for single-mode operation. This method for obtaining single-mode output from a pulsed TEA laser is completely automatic and very straightforward to implement.
Journal de Physique Lettres, 1979
2014 Nous avons effectué l'étude spectroscopique de la molécule CF235Cl2 dans la région de 923 cm... more 2014 Nous avons effectué l'étude spectroscopique de la molécule CF235Cl2 dans la région de 923 cm-1 avec, d'une part, un spectre de laser à diode donnant la branche Q de la bande 03BD6 et, d'autre part, un spectre par transformée de Fourier de 910 à 935 cm-1. La superposition des nombreuses bandes d'absorption dans cette région donne une grande densité de raies non isolées qui rend leur identification très difficile même à la résolution du laser à diode (0,001 5 cm-1). Nous avons, à partir de la branche Q, déterminé des constantes rotationnelles qui permettent de reproduire les raies jusqu'à J = 78. A l'aide de ces constantes, nous avons calculé la branche R et le spectre calculé est en bon accord avec le spectre par transformée de Fourier enregistré avec une résolution de 0,04 cm-1. Abstract. 2014 The spectral region near 923 cm-1 is studied by using diode laser spectra of the dominant Q-branch belonging to the CF2 35Cl2 molecule along with Fourier transform spectra of the entire region from 910 to 935 cm-1. The overlap of the many absorption bands and also the large density of lines make quantum identification difficult because even at the resolving power of the diode laser (0.001 5 cm-1) the lines observed are not pure.
Measurements of the absorption of CO2 laser radiation in the 9.4 micron band by pressure broadene... more Measurements of the absorption of CO2 laser radiation in the 9.4 micron band by pressure broadened water vapor samples are summarized. The water vapor temperatures used were 25, 30, and 35 C.
Three-Dimensional Imaging and Remote Sensing Imaging, 1988
Frequency agility in remote-sensor lasers permits differential absorption and differential scatte... more Frequency agility in remote-sensor lasers permits differential absorption and differential scattering measurements to be conducted for quantitative studies of atmospheric molecules and aerosols. High spectral purity in laser transmitter pulses allows heterodyne detection to be used for improved SNR, and renders the study of small, Doppler-induced frequency shifts due to the relative motion between target and observer possible. Attention is
The Journal of Physical Chemistry, 1976
We report the results of a new technique for the determination of the equilibrium constant for th... more We report the results of a new technique for the determination of the equilibrium constant for the reactions N204 + 2N02. Fourier transform spectroscopy was used to record infrared spectra of the u2 band of NO2 near 13.3 I*. Spectra were recorded alternately through two absorption cells of different lengths. Working within the validity of the Beer-Lambert law of absorption of radiation, an equation is derived which relates the equilibrium constant to pairs of gas pressures which give the same spectral absorbance of NO2 in the two unequal cells. No knowledge of the absorption coefficient is needed using this technique. All samples were pressurized to 740 Torr with high-purity nitrogen and measurements were taken a t room temperature (296 f 1 K). Using this two cell technique, we have found K,, = 0.14 f 0.02 atm at room temperature.
Optical Diagnostics and Sensing XI: Toward Point-of-Care Diagnostics; and Design and Performance Validation of Phantoms Used in Conjunction with Optical Measurement of Tissue III, 2011
As optical technology progresses through the translational research pipeline, phantoms are becomi... more As optical technology progresses through the translational research pipeline, phantoms are becoming more important as verification tools to demonstrate proper performance of the devices before clinical studies. Because of the wide range of optical methodologies, there can be no single phantom that is useful for all modes of imaging, but protocols for phantom use should be organized to stand as
Fourier, Hadamard, and Hilbert Transforms in Chemistry, 1982
Fourier transform spectroscopy, a technique which Mertz1 once called “a disagreeable indirect met... more Fourier transform spectroscopy, a technique which Mertz1 once called “a disagreeable indirect method to record a spectrum”, has matured in recent years into a widely used and accepted spectroscopic technique. The rapid increase in the popularity of Fourier spectroscopy can be attributed, at least in part, to the technological advances in computer hardware and to the development of the Cooley-Tukey alogrithm2 for computing Fourier transforms quickly. Both of these developments have helped to popularize Fourier spectroscopy and have given strong impetus to its growing appeal and commercialization by significantly reducing the time required to compute a final spectrum from the recorded interferogram.
Molecular-Guided Surgery: Molecules, Devices, and Applications VI, 2020
The large growth in fluorescence guided surgical (FGS) imaging have radically different physical ... more The large growth in fluorescence guided surgical (FGS) imaging have radically different physical designs, image processing approaches and performance requirements, making it nearly impossible to specify uniform performance goals. Yet, utilization of different devices in clinical trials indicates some need for common knowledge bases and quality assessment goals to ensure accurate and effective translation occurs. This task group identified fundamental image quality characteristics corresponding objective test methods that should be determined across a variety of FGS devices. This report outlines a cohort of explicit test methods and specific tissue simulating phantom tests, with the goal of suggested guidelines that will allow evaluative and comparative studies on system performance. This initiative is expected to help users and developers focus on needs while converging towards future goals.
L'invention concerne un procede et un systeme permettant de normaliser des spectres optiques ... more L'invention concerne un procede et un systeme permettant de normaliser des spectres optiques par normalisation de segment non uniforme. Un spectre est obtenu et represente en fonction de longueur d'onde en tant qu'amplitude a chacune d'une pluralite de longueurs d'onde. On choisit au moins un segment du spectre, lequel segment est delimite par une longueur d'onde superieure et une longueur d'onde inferieure. On calcule un facteur de normalisation comme somme des surfaces pour chacun des segments choisis. On normalise le spectre en divisant au moins une amplitude de ce spectre par le facteur de normalisation. Les spectres peuvent etre choisis avec differentes gammes de longueurs d'onde, c'est-a-dire, les segments peuvent etre non uniformes. On peut categoriser des specimen d'essai sur la base d'une analyse des spectres normalises. En particulier, le specimen d'essai peut etre du tissu cervical humain et on peut en determiner l'etat ...
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Papers by Robert Nordstrom