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Journal articles on the topic 'Tomography'

To see the other types of publications on this topic, follow the link: Tomography.

Author: Grafiati

Published: 4 June 2021

Last updated: 30 July 2024

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1

Cristini, Valentino, Jan Tippner, Barbora Vojáčková, and Vinko Paulić. "Comparison of variability in results of acoustic tomographs in pedunculate oak (Quercus robur L.)." BioResources 16, no. 2 (March 5, 2021): 3046–58. http://dx.doi.org/10.15376/biores.16.2.3046-3058.

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Tree acoustic tomography is a widely used device supported method for tree stability assessment. In this work, the results of the three most commonly used devices for acoustic tomography of standing trees (ARBOTOM®, ArborSonic®, and PiCUS®) were compared on selected individuals of sessile oak in Brno, Czech Republic. According to the statistical analysis, there was a significant difference between values measured by the PiCUS® acoustic tomograph and those measured by both the ARBOTOM and ArborSonic® acoustic tomographs. Based on the measured data, velocities measured by PiCUS® were considerably lower than those recorded by the other acoustic tomographs (ARBOTOM® and ARBORSONIC®). Measured radial and tangential velocities differed from each other. In data obtained from the defective cross-sections, this difference was attenuated. Image reconstructions (tomograms) from the acoustic tomographs differed from each other. Complex shapes of defects in standing trees can significantly influence acoustic tomography results. According to the statistical analysis, there was no significant relationship between sound velocity and density, while there was a relatively strong positive correlation between sound velocity and moisture content.

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2

Prettyraan, T. H., R. P. Gardner, J. C. Russ, and K. Verghese. "Evaluation of a Combined Transmission and Scattering Approach to Composition Imaging of Industrial Samples." Advances in X-ray Analysis 35, B (1991): 1235–41. http://dx.doi.org/10.1154/s0376030800013549.

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Composition imaging of industrial samples has been reported using dual energy and multiple energy transmission computed tomography [1,2]. The simplest approach utilizes monoenergetic sources to obtain tomographs of a sample at two different energies. Each tomograph represents the linear attenuation coefficient distribution of the sample at the given source energy.

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3

Amelina, Inna D., Lev N. Shevkunov, Aleksey M. Karachun, Alexander E. Mikhnin, and Denis V. Nesterov. "Diagnosis and t-staging of gastric cancer: comparison of standard computed tomography and computed-tomographic pneumogastrography." Bulletin of the Russian Military Medical Academy 23, no. 2 (July 12, 2021): 99–106. http://dx.doi.org/10.17816/brmma70384.

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The advantages of computed tomographic pneumogastrography with the possibility of three-dimensional visualization and virtual gastroscopy in diagnosing gastric cancer are considered. The study included 479 patients with histologically diagnosed gastric cancer who were treated at the National Medical Research Center of Oncology named after N.N. Petrov from 2011 to 2018. 232 patients received preoperative chemotherapy. All patients underwent surgery: 70 in the volume of endoscopic dissection, 40 proximal subtotal resection, 166 distal subtotal resection, 203 gastrectomy. All patients at the preoperative stage underwent staging computed tomography on a 64-slice X-ray computed tomograph: 208 patients underwent computed tomography according to the standard protocol without targeted preparation of the stomach for the study, 271 patients with targeted preparation of the stomach for the study according to the computed tomographic pneumogastrography protocol. The sensitivity of the computed tomography in assessing the T-stage was assessed by comparison with pathomorphological data. Of the 208 patients who underwent computed tomography according to the standard protocol, a gastric cancer was detected in 111 (53.4%), out of 271 patients who underwent computed tomography pneumogastrography, a gastric cancer was detected in 267 (98.52%), which is a statistically significant difference in comparing computed tomography methods (Pearson, 144.223, df = 1; p 0.001). There are statistically significant differences when comparing computed tomography according to the standard protocol and computed tomographic pneumogastrography in detecting gastric cancer for all tumor categories: T/yT1 8.2 and 94.4% (Pearson, 99.205, df = 1; p 0.001), T/yT2 47.8 and 100% (Pearson, 24.681, df = 1; p 0.001), T/yT3 72.3 and 100% (Pearson, 33.114, df = 1; p 0.001), T/yT4 90.0 and 100% (Pearson, 4.789, df = 1; p = 0.029) respectively. There are also statistically significant differences when comparing the sensitivity of computed tomography according to the standard protocol and computed tomographic pneumogastrography in determining tumor invasion for all tumor categories: T/yT1 0 and 69.4% (Pearson, 67.880, df = 1; p 0.001), T/yT2 26.1 and 71.1% (Pearson, 11.666, df = 1; p 0.001), T/yT3 32.9 and 84.6% (Pearson, 54.900, df = 1; p 0.001), T/yT4 73.3 and 95.7% (Pearson, 7.916, df = 1; p = 0.005) respectively. In general, the sensitivity of the computed tomography according to the standard protocol for determining the T-stage of gastric cancer was 28.4%, computed tomographic pneumogastrography 77.1% (Pearson, 113.505, df = 1; p 0.001). Computed tomographic pneumogastrography with the possibility of three-dimensional visualization and virtual gastroscopy significantly increases the indicators of the effectiveness of diagnosing gastric cancer both early forms (category T1) and with deeper invasion (categories T2T4), demonstrates high sensitivity in determining T/yT-stages.

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4

Kłosowski, Grzegorz, Tomasz Rymarczyk, Tomasz Cieplak, Konrad Niderla, and Łukasz Skowron. "Quality Assessment of the Neural Algorithms on the Example of EIT-UST Hybrid Tomography." Sensors 20, no. 11 (June 11, 2020): 3324. http://dx.doi.org/10.3390/s20113324.

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The paper presents the results of research on the hybrid industrial tomograph electrical impedance tomography (EIT) and ultrasonic tomography (UST) (EIT-UST), operating on the basis of electrical and ultrasonic data. The emphasis of the research was placed on the algorithmic domain. However, it should be emphasized that all hardware components of the hybrid tomograph, including electronics, sensors and transducers, have been designed and mostly made in the Netrix S.A. laboratory. The test object was a tank filled with water with several dozen percent concentration. As part of the study, the original multiple neural networks system was trained, the characteristic feature of which is the generation of each of the individual pixels of the tomographic image, using an independent artificial neural network (ANN), with the input vector for all ANNs being the same. Despite the same measurement vector, each of the ANNs generates its own independent output value for a given tomogram pixel, because, during training, the networks get their respective weights and biases. During the tests, the results of three tomographic methods were compared: EIT, UST and EIT-UST hybrid. The results confirm that the use of heterogeneous tomographic systems (hybrids) increases the reliability of reconstruction in various measuring cases, which is used to solve quality problems in managing production processes.

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5

Davis, Cole, and Wayne Kuang. "Optical coherence tomography: a novel modality for scrotal imaging." Canadian Urological Association Journal 3, no. 4 (May 1, 2013): 319. http://dx.doi.org/10.5489/cuaj.1128.

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Background: For patients with nonobstructive azoospermia,sperm retrieval rates remain modest. We describe the use ofoptical coherence tomography to improve retrieval rates and todecrease tissue destruction.Methods: Four patients underwent diagnostic testicular biopsyand imaging with the Niris optical coherence tomography de -vice. We performed a descriptive comparison between optic alcoherence tomographic images and conventional histology.Results: The measured seminiferous tubule diameter differed by16 μm between comparative imaging from optical coherencetomography and conventional histology using hematoxylin andeosin staining.Conclusion: We illustrate the usefulness of optical coherencetomography in the setting of testicular biopsy and the managementof nonobstructive azoospermia.Contexte : Chez les patients atteints d'azoospermie non obstructive,les taux de collecte de spermatozoïdes demeurent modestes.Nous décrivons le recours à une tomographie optiquecohérente pour améliorer les taux de collecte et réduire ladestruction tissulaire.Méthodes : Quatre patients ont subi une biopsie testiculaire diagnostiqueet une épreuve d'imagerie à l'aide d'un appareil Nirisde tomographie optique cohérente. Une comparaison descriptivea été effectuée entre les images obtenues par tomographieoptique cohérente et les résultats des épreuves histologiquesstandard.Résultats : La différence dans le diamètre des tubules séminifèresmesuré par tomographie optique cohérente et par coloration histologiqueà l'hématoxyline-éosine n'était que de 16 μm.Conclusion : Nous présentons une étude descriptive illustrant l’uti -lité de la tomographie optique cohérente pendant une biopsietesticulaire en vue de la prise en charge d'une azoospermie nonobstructive.

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6

Kitazawa, Takahiro, and Takanori Nomura. "Refractive index tomography based on optical coherence tomography and tomographic reconstruction algorithm." Japanese Journal of Applied Physics 56, no. 9S (August 24, 2017): 09NB03. http://dx.doi.org/10.7567/jjap.56.09nb03.

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7

Machnio, Piotr, Michał Ziemczonok, and Małgorzata Kujawińska. "Reconstruction enhancement via projection screening in holographic tomography." Photonics Letters of Poland 13, no. 2 (June 30, 2021): 37. http://dx.doi.org/10.4302/plp.v13i2.1104.

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This paper presents an algorithm for automatic detection of erroneous amplitude and phase components of a sample’s optical field, acquired by a holographic tomograph with a limited angle of projection. By applying image processing methods and statistical analysis to find and remove unfit projections, the quality of tomographic reconstruction of a 3D refractive index distribution of an object is greatly improved. The proposed methods can find their application in preprocessing of data in holographic tomography. Full Text: PDF ReferencesA. Kuś, W. Krauze, P. L. Makowski, and M. Kujawińska, "Holographic tomography: hardware and software solutions for 3D quantitative biomedical imaging (Invited paper)", ETRI Journal, 41, 1 (2019). CrossRef V. Balasubramani et al., "Phase unwrapping in ICF target interferometric measurement via deep learning", Appl. Opt., 60, 10 (2021). CrossRef Y. Park, C. Depeursinge, and G. Popescu, "Quantitative phase imaging in biomedicine", Nature Photonics, 12, 10 (2018). CrossRef W. Krauze, P. Makowski, M. Kujawińska, and A. Kuś, "Generalized total variation iterative constraint strategy in limited angle optical diffraction tomography", Opt. Express, 24, 5 (2016). CrossRef D. Ryu et al., "A non-calorimetric approach for investigating the moisture-induced ageing of a pyrotechnic delay material using spectroscopies", Sci Rep, 9, 1 (2019). CrossRef B. S. Lipkin, Picture Processing and Psychopictorics. (Saint Louis, Elsevier Science 2014). DirectLink A. M. Taddese, N. Verrier, M. Debailleul, J.-B. Courbot, and O. Haeberlé, "Optimizing sample illumination scanning in transmission tomographic diffractive microscopy", Appl. Opt., 60, 6 (2021). CrossRef

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8

Takiguchi, Takashi. "Ultrasonic Tomographic Technique and Its Applications." Applied Sciences 9, no. 5 (March 11, 2019): 1005. http://dx.doi.org/10.3390/app9051005.

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X-ray tomography and magnetic resonance imaging (MRI) are excellent techniques for non-destructive or non-invasive inspections, however, they have shotcomings including the expensive cost in both the devices themselves and their protection facilities, the harmful side effects of the X-rays to human bodies and to the environment. In view of this argument, it is necessary to develop new, inexpensive, safe and reliable tomographic techniques, especially in medical imaging and non-destructive inspections. There are new tomographic techniques under development such as optical tomography, photo-acoustic tomography, ultrasonic tomography and so on, from which we take ultrasonic tomography as the topic in this paper. We introduce a review of the known ultrasonic tomographic techniques and discuss their future development.

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9

Kalnaya, O. A., and Yu S. Kurskoy. "Femtosecond Optical Tomography." Metrology and instruments, no. 2 (May 21, 2020): 57–60. http://dx.doi.org/10.33955/2307-2180(2)2020.57-60.

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The aim of the work is development of medical optical tomography technologies. The physical principles, tasks, and boundary possibilities of the optical tomography systems are considered. The autors propose to use the femtosecond lasers, operating in the «optical comb» mode, as a lught source in optical tomography system. The advantages of this source uses were analyzed and resolution power of femtosecond optical tomographs was calculated in the artical.

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10

Kitazawa, Takahiro, and Takanori Nomura. "Erratum: “Refractive index tomography based on optical coherence tomography and tomographic reconstruction algorithm”." Japanese Journal of Applied Physics 57, no. 8 (July 10, 2018): 089201. http://dx.doi.org/10.7567/jjap.57.089201.

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11

Natterer, Frank. "Numerical methods in tomography." Acta Numerica 8 (January 1999): 107–41. http://dx.doi.org/10.1017/s0962492900002907.

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In this article we review the image reconstruction algorithms used in tomography. We restrict ourselves to the standard problems in the reconstruction of function from line or plane integrals as they occur in X-ray tomography, nuclear medicine, magnetic resonance imaging, and electron microscopy. Nonstandard situations, such as incomplete data, unknown orientations, local tomography, and discrete tomography are not dealt with. Nor do we treat nonlinear tomographic techniques such as impedance, ultrasound, and near-infrared imaging.

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12

Klebanov, Lev B., and Svetlozar T. Rachev. "Computer Tomography and Quantum Mechanics." Advances in Applied Probability 29, no. 3 (September 1997): 595–606. http://dx.doi.org/10.2307/1428078.

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In this paper we study some topics of interest to specialists in computer tomography. These are the following. (a) The Radon transform and its applications to computer tomography. (b) Problems of computer tomography with partially known data. Estimates of stability will be given for different types of distance in the space of probability distributions. We consider the problem with partially known tomographic data as a stability problem for appropriately chosen distances. This approach allows us to give a solution of the so-called computer tomography paradox. (c) The relation of quantum mechanics to computer tomography. An intriguing method for ‘measuring' wavefunctions by tomographic methods (CAT scans) opens a new approach to various problems in quantum mechanics. Using the method outlined for the solution of the computer tomography paradox, we derive inequalities that estimate the amount of information on the wavefunctions resulting from real CAT scans, i.e. CAT scans based on the finite number of measured marginals (projections) of the Wigner distributions. In conclusion, we propose a new version of the mathematical justification of CAT scans.

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Klebanov, Lev B., and Svetlozar T. Rachev. "Computer Tomography and Quantum Mechanics." Advances in Applied Probability 29, no. 03 (September 1997): 595–606. http://dx.doi.org/10.1017/s0001867800028263.

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In this paper we study some topics of interest to specialists in computer tomography. These are the following. (a) The Radon transform and its applications to computer tomography. (b) Problems of computer tomography with partially known data. Estimates of stability will be given for different types of distance in the space of probability distributions. We consider the problem with partially known tomographic data as a stability problem for appropriately chosen distances. This approach allows us to give a solution of the so-called computer tomography paradox. (c) The relation of quantum mechanics to computer tomography. An intriguing method for ‘measuring' wavefunctions by tomographic methods (CAT scans) opens a new approach to various problems in quantum mechanics. Using the method outlined for the solution of the computer tomography paradox, we derive inequalities that estimate the amount of information on the wavefunctions resulting from real CAT scans, i.e. CAT scans based on the finite number of measured marginals (projections) of the Wigner distributions. In conclusion, we propose a new version of the mathematical justification of CAT scans.

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14

Vamvakeros, Antonios, Simon D. M. Jacques, Marco Di Michiel, Pierre Senecal, Vesna Middelkoop, Robert J. Cernik, and Andrew M. Beale. "Interlaced X-ray diffraction computed tomography." Journal of Applied Crystallography 49, no. 2 (March 1, 2016): 485–96. http://dx.doi.org/10.1107/s160057671600131x.

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An X-ray diffraction computed tomography data-collection strategy that allows, post experiment, a choice between temporal and spatial resolution is reported. This strategy enables time-resolved studies on comparatively short timescales, or alternatively allows for improved spatial resolution if the system under study, or components within it, appear to be unchanging. The application of the method for studying an Mn–Na–W/SiO2 fixed-bed reactor in situ is demonstrated. Additionally, the opportunities to improve the data-collection strategy further, enabling post-collection tuning between statistical, temporal and spatial resolutions, are discussed. In principle, the interlaced scanning approach can also be applied to other pencil-beam tomographic techniques, like X-ray fluorescence computed tomography, X-ray absorption fine structure computed tomography, pair distribution function computed tomography and tomographic scanning transmission X-ray microscopy.

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15

Druzhinina, P. S., L. A. Chipiga, V. Yu Golikov, A. V. Vodovatov, S. Yu Bazhin, E. N. Shleenkova, G. V. Berkovich, I. V. Soldatov, Z. A. Lantukh, and K. V. Tolkachev. "Improving the approach to calculating shielding in computed tomography rooms." Radiatsionnaya Gygiena = Radiation Hygiene 17, no. 2 (July 7, 2024): 64–75. http://dx.doi.org/10.21514/1998-426x-2024-17-2-64-75.

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The study assessed the acceptability of the currently existing approach to calculating shielding in computed tomography rooms and formulated proposals for its improvement, taking into account the parameters of research in domestic medical practice. It is proposed to use the dose-length product as the main measured parameter in the new approach to calculating shielding. Typical tomograph workload values of dose-length product, typical for examinations in the Russian Federation, were assessed. Using thermoluminescent detectors, the experimental assessment of the distribution of absorbed dose in the air in a computed tomography room was carried out. The experimental results showed that the distribution of of X-ray exposure in the central plane is not isotropic. Due to the attenuation of exposure by the gantry design, “shadow” zones are observed, where the absorbed dose reduction in the air reaches 10-13 times compared to its level in the direction of couch movement. Based on the results of measurements of the distribution of absorbed dose in air, the relative scatter coefficients were calculated. The workload was determined for 7 tomographs (1 in St. Petersburg and 6 in Moscow). For each tomograph, the average weekly number of head and body examinations and the values of dose-length product for these areas were assessed, taking into account the number of multiphase examinations. The obtained workload values turned out to be one or two orders of magnitude higher than those currently used in calculating shielding. Based on the results of the study and literature data, the work proposes a new approach to calculating shielding in computed tomography rooms, based on the value of measured dose-length product during the examination and allowing to take into account the specifics of the operation of the device.

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Wen, Debao, Dengkui Mei, and Yanan Du. "Imaging the Three-Dimensional Ionospheric Structure with a Blob Basis Functional Ionospheric Tomography Model." Sensors 20, no. 8 (April 12, 2020): 2182. http://dx.doi.org/10.3390/s20082182.

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A new ionospheric tomography model is presented in this work. In the new model, the traditional voxel basis function is replaced by the blob basis function. Due to the overlapping nature of their rotational symmetric basis functions, the new model introduces certain weighting from nearby tomographic spherical blobs. To confirm the feasibility of the new tomography model, a numerical simulation scheme is devised, and the simulation demonstrates that the reconstructed quality of the blob basis tomographic model is higher than that of the voxel basis tomographic model. Meanwhile, the variable blob radius is adopted in order to improve the efficiency of the new model. Finally, the new ionospheric tomography model is applied to reconstruct the temporal-spatial distribution of ionospheric electron density using actual global navigation satellite system observations. The comparisons between the tomographic profiles and those obtained from ionosonde data further demonstrate the reliability and the superiority of the new ionospheric tomography model.

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Barbey, N., C. Guennou, and F. Auchère. "TomograPy: A Fast, Instrument-Independent, Solar Tomography Software." Solar Physics 283, no. 1 (July 1, 2011): 227–45. http://dx.doi.org/10.1007/s11207-011-9792-8.

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18

Tassiopoulou, Styliani, Georgia Koukiou, and Vassilis Anastassopoulos. "Algorithms in Tomography and Related Inverse Problems—A Review." Algorithms 17, no. 2 (February 5, 2024): 71. http://dx.doi.org/10.3390/a17020071.

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In the ever-evolving landscape of tomographic imaging algorithms, this literature review explores a diverse array of themes shaping the field’s progress. It encompasses foundational principles, special innovative approaches, tomographic implementation algorithms, and applications of tomography in medicine, natural sciences, remote sensing, and seismology. This choice is to show off the diversity of tomographic applications and simultaneously the new trends in tomography in recent years. Accordingly, the evaluation of backprojection methods for breast tomographic reconstruction is highlighted. After that, multi-slice fusion takes center stage, promising real-time insights into dynamic processes and advanced diagnosis. Computational efficiency, especially in methods for accelerating tomographic reconstruction algorithms on commodity PC graphics hardware, is also presented. In geophysics, a deep learning-based approach to ground-penetrating radar (GPR) data inversion propels us into the future of geological and environmental sciences. We venture into Earth sciences with global seismic tomography: the inverse problem and beyond, understanding the Earth’s subsurface through advanced inverse problem solutions and pushing boundaries. Lastly, optical coherence tomography is reviewed in basic applications for revealing tiny biological tissue structures. This review presents the main categories of applications of tomography, providing a deep insight into the methods and algorithms that have been developed so far so that the reader who wants to deal with the subject is fully informed.

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Bayford, R. H. "BIOIMPEDANCE TOMOGRAPHY (ELECTRICAL IMPEDANCE TOMOGRAPHY)." Annual Review of Biomedical Engineering 8, no. 1 (August 2006): 63–91. http://dx.doi.org/10.1146/annurev.bioeng.8.061505.095716.

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20

Townsend, David W. "Positron Emission Tomography/Computed Tomography." Seminars in Nuclear Medicine 38, no. 3 (May 2008): 152–66. http://dx.doi.org/10.1053/j.semnuclmed.2008.01.003.

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21

Kelly, Thomas F. "Atomic-Scale Analytical Tomography." Microscopy and Microanalysis 23, no. 1 (February 2017): 34–45. http://dx.doi.org/10.1017/s1431927617000125.

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AbstractThe concept of atomic-scale tomography has been proposed in the past decade as a technique that could deliver the position of all atoms with high precision and their elemental (isotopic) identity. The technique was never intended to be limited to merely structural information and there is clearly a rich array of additional analytical information that can be brought to bear on such tomographs. In this paper, some of these types of information are considered and the implications are explored. The fuller realm of this analytical and structural information may be called atomic-scale analytical tomography.

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22

Zatoń, Patrycja, Paweł Kozakiewicz, and Piotr Mańkowski. "Investigation of round Scots pine wood WC01 class using X-ray computer tomography." Annals of WULS, Forestry and Wood Technology 117 (April 30, 2022): 97–105. http://dx.doi.org/10.5604/01.3001.0016.0487.

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Investigation of round Scots pine wood WC01 class using X-ray computer tomography. Scots pine is the most widespread type of wood in Poland with wide industrial use. The typical starting material used for the production of layered floor elements are logs of WC01 class (class according to the Polish Standard PN-D-95008: 1992 and Order no 72 - GM-900-5 / 2013 of General Director of the State Forests in Poland). Using X-ray computed tomography, tests of fresh wood in the bark were carried out, confirming the full suitability of this technique for the precise assessment of wood density as well as its grain and distribution of anatomical defects (knots). The different level of humidity of sapwood and heartwood in fresh wood is visible in tomographic images and translates into a much higher recorded density of the wetter zone of sapwood. Calibration of the tomograph used made it possible to convert the Hounsfield density scale into actual densities expressed in kg/m3.

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Kübel, Christian, Dirk Niemeyer, Robert Cieslinski, and Steve Rozeveld. "Electron Tomography of Nanostructured Materials – Towards a Quantitative 3D Analysis with Nanometer Resolution." Materials Science Forum 638-642 (January 2010): 2517–22. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.2517.

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Electron tomography has developed into a powerful technique to image the 3D structure of complex materials with nanometer resolution. Both, TEM and HAADF-STEM tomography exhibit tremendous possibilities to visualize nanostructured materials for a wide range of applications. Electron tomography is not only a qualitative tool to visualize nano¬structures, but recently electron tomographic results are also exploited to obtain quantitative measurements in 3D. We evaluated the reconstruction and segmentation process for a heterogeneous catalyst and, in particular, tried to assess the reliability and accuracy of the quantification process. Furthermore, a quantitative analysis of electron tomographic results was compared to macroscopic measurements.

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Skvortsova, E. B., E. V. Shein, K. N. Abrosimov, K. M. Gerke, D. V. Korost, K. A. Romanenko, V. S. Belokhin, and A. V. Dembovetskii. "Tomography in soil science." Dokuchaev Soil Bulletin 86 (December 15, 2016): 28–34. http://dx.doi.org/10.19047/0136-1694-2016-86-28-34.

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Jørgensen, J. S., E. Ametova, G. Burca, G. Fardell, E. Papoutsellis, E. Pasca, K. Thielemans, et al. "Core Imaging Library - Part I: a versatile Python framework for tomographic imaging." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2204 (July 5, 2021): 20200192. http://dx.doi.org/10.1098/rsta.2020.0192.

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We present the Core Imaging Library (CIL), an open-source Python framework for tomographic imaging with particular emphasis on reconstruction of challenging datasets. Conventional filtered back-projection reconstruction tends to be insufficient for highly noisy, incomplete, non-standard or multi-channel data arising for example in dynamic, spectral and in situ tomography. CIL provides an extensive modular optimization framework for prototyping reconstruction methods including sparsity and total variation regularization, as well as tools for loading, preprocessing and visualizing tomographic data. The capabilities of CIL are demonstrated on a synchrotron example dataset and three challenging cases spanning golden-ratio neutron tomography, cone-beam X-ray laminography and positron emission tomography. This article is part of the theme issue ‘Synergistic tomographic image reconstruction: part 2’.

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Zatoń, Patrycja, Paweł Kozakiewicz, and Piotr Mańkowski. "Relationship between the compressive strength, density and the width of the annual rings in a high-guality part of timber of Scots pine (Pinus sylvestris L.) wood." Annals of WULS, Forestry and Wood Technology 121 (March 29, 2023): 135–41. http://dx.doi.org/10.5604/01.3001.0054.4391.

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Investigation of round Scots pine wood WC01 class using X-ray computer tomography. Scots pine is the most widespread type of wood in Poland with wide industrial use. The typical starting material used for the production of layered floor elements are logs of WC01 class (class according to the Polish Standard PN-D-95008: 1992 and Order no 72 - GM-900-5 / 2013 of General Director of the State Forests in Poland). Using X-ray computed tomography, tests of fresh wood in the bark were carried out, confirming the full suitability of this technique for the precise assessment of wood density as well as its grain and distribution of anatomical defects (knots). The different level of humidity of sapwood and heartwood in fresh wood is visible in tomographic images and translates into a much higher recorded density of the wetter zone of sapwood. Calibration of the tomograph used made it possible to convert the Hounsfield density scale into actual densities expressed in kg/m3.

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27

Luan, Tian, Zetong Li, Congcong Zheng, Xueheng Kuang, Xutao Yu, and Zaichen Zhang. "Quantum Tomography: From Markovianity to Non-Markovianity." Symmetry 16, no. 2 (February 2, 2024): 180. http://dx.doi.org/10.3390/sym16020180.

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The engineering of quantum computers requires the reliable characterization of qubits, quantum operations, and even the entire hardware. Quantum tomography is an indispensable framework in quantum characterization, verification, and validation (QCVV), which has been widely accepted by researchers. According to the tomographic target, quantum tomography can be categorized into quantum state tomography (QST), quantum process tomography (QPT), gate set tomography (GST), process tensor tomography (PTT), and instrument set tomography (IST). Standard quantum tomography toolkits generally consist of basic linear inverse methods and statistical maximum likelihood estimation (MLE)-based methods. Furthermore, the performance of standard methods, including effectiveness and efficiency, has been further developed by exploiting Bayesian estimation, neural networks, matrix completion techniques, etc. In this review, we introduce the fundamental quantum tomography techniques, including QST, QPT, GST, PTT, and IST. We first introduce the details of basic linear inverse methods. Then, the framework of MLE methods with constraints is summarized. Finally, we briefly introduce recent further research in developing the performance of tomography, utilizing some symmetry properties of the target. This review provides a primary getting-start in developing quantum tomography, which promotes quantum computer development.

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Di Matteo, Olivia, John Gamble, Chris Granade, Kenneth Rudinger, and Nathan Wiebe. "Operational, gauge-free quantum tomography." Quantum 4 (November 17, 2020): 364. http://dx.doi.org/10.22331/q-2020-11-17-364.

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As increasingly impressive quantum information processors are realized in laboratories around the world, robust and reliable characterization of these devices is now more urgent than ever. These diagnostics can take many forms, but one of the most popular categories is tomography, where an underlying parameterized model is proposed for a device and inferred by experiments. Here, we introduce and implement efficient operational tomography, which uses experimental observables as these model parameters. This addresses a problem of ambiguity in representation that arises in current tomographic approaches (the gauge problem). Solving the gauge problem enables us to efficiently implement operational tomography in a Bayesian framework computationally, and hence gives us a natural way to include prior information and discuss uncertainty in fit parameters. We demonstrate this new tomography in a variety of different experimentally-relevant scenarios, including standard process tomography, Ramsey interferometry, randomized benchmarking, and gate set tomography.

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Sutton, Mark, Imran Rahman, and Russell Garwood. "VIRTUAL PALEONTOLOGY—AN OVERVIEW." Paleontological Society Papers 22 (September 2016): 1–20. http://dx.doi.org/10.1017/scs.2017.5.

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AbstractVirtual paleontology is the study of fossils through three-dimensional digital visualizations; it represents a powerful and well-established set of tools for the analysis and dissemination of fossil data. Techniques are divisible into tomographic (i.e., slice-based) and surface-based types. Tomography has a long predigital history, but the recent explosion of virtual paleontology has resulted primarily from developments in X-ray computed tomography (CT), and of surface-based technologies (e.g., laser scanning). Destructive tomographic methods include forms of physical-optical tomography (e.g., serial grinding); these are powerful but problematic techniques. Focused Ion Beam (FIB) tomography is a modern alternative for microfossils; it is also destructive but is capable of extremely high resolutions. Nondestructive tomographic methods include the many forms of CT, which are the most widely used data-capture techniques at present, but are not universally applicable. Where CT is inappropriate, other nondestructive technologies (e.g., neutron tomography, magnetic resonance imaging, optical tomography) can prove suitable. Surface-based methods provide portable and convenient data capture for surface topography and texture, and might be appropriate when internal morphology is not of interest; technologies include laser scanning, photogrammetry, and mechanical digitization. Reconstruction methods that produce visualizations from raw data are many and various; selection of an appropriate workflow will depend on many factors, but is an important consideration that should be addressed prior to any study. The vast majority of three-dimensional fossils can now be studied using some form of virtual paleontology, and barriers to broader adaptation are being eroded. Technical issues regarding data sharing remain problematic. Technological developments continue; those promising tomographic recovery of compositional data are of particular relevance to paleontology.

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Frolovtsev, Dmitry N., Sergey A. Magnitskiy, and Andrey V. Demin. "Quantum tomograph for measurement and characterization of quantum states of biphoton sources." Izmeritel`naya Tekhnika, no. 4 (April 2020): 20–26. http://dx.doi.org/10.32446/0368-1025it.2020-4-20-26.

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The method and prototype of a device for characterizing of biphoton light sources based on spontaneous parametric downdonversion by quantum tomography are described. The prototype is an experimental implementation of a specialized quantum tomograph designed to measure the quantum polarization states of radiation generated by biphoton sources. Specially developed software will determine the statistical characteristics of the measured quantum state, calculate the tomographic and likelihood estimations of the density matrix, calculate the measurement errors of the density matrix elements and evaluate the quality of the quantum state of biphotons.

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Yao, Yibin, Chen Liu, Chaoqian Xu, Yu Tan, and Mingshan Fang. "A Refined Tomographic Window for GNSS-Derived Water Vapor Tomography." Remote Sensing 12, no. 18 (September 15, 2020): 2999. http://dx.doi.org/10.3390/rs12182999.

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Global navigation satellite system (GNSS) tomography can effectively sense the three-dimensional structure of tropospheric water vapor (WV) using the GNSS observations. Numerous studies have utilized a tomographic window to include more epochs of observations, which significantly increases the number of valid signals. However, considering the tomography grid limits, a massive number of valid signals inevitably exhibits linear dependence. This dependence makes it impossible to improve the rank score of the tomography coefficient matrix by blindly introducing a large number of valid rays. Furthermore, excessive valid signals may lead to a high condition number in the coefficient matrix (ill-condition problem), which causes unstable results using the GNSS-WV tomography. Considering these problems, we proposed an improved tomographic approach, which applies a refined tomographic window. It differs from the general tomographic window in that the window is refined to traverse the valid signals available 15 min before and after the target epoch while retaining only the linearly independent parts (characteristic signal). Compared to the conventional method, the proposed method can filter the characteristic signal, which increases the rank score of the coefficient matrix and improves the stability of the tomography model. In this paper, we used GNSS observations from the Hong Kong Satellite Positioning Reference Station Network (SatRef) to validate the performance of the proposed method over the day-of-year (DOY) periods of 130–132, 2019 and 146–148, 2019. The numerical results showed that, by using a refined tomographic window, the proposed method obtained superior WV products in comparison with that of the conventional method.

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32

Ko, Dae-Sik. "Multiple-Transducer Scheme for Scanning Tomographic Acoustic Microscopy Using Transverse Waves." Ultrasonic Imaging 19, no. 4 (October 1997): 294–304. http://dx.doi.org/10.1177/016173469701900405.

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We propose a new type of multiple-transducer scheme with functions of multiple-angle and multiple-frequency tomography for scanning tomographic acoustic microscopy (STAM) using transverse waves. We review the data acquisition system and mode conversion of the acoustic waves for STAM and the multiple-angle and multiple-frequency tomography. Our multiple-transducer scheme has three insonification angles and three resonance frequencies in order to operate, in the transverse wave mode, multiple-angle and multiple frequency tomography for STAM. In order to evaluate the performance of our transducer scheme, we have simulated tomographic reconstruction with a back-and-forth propagation algorithm. Simulation results show that our multiple-transducer scheme is capable of obtaining good resolution with transverse wave mode and multiple-frequency tomography. We also show that our multiple-transducer scheme is an efficient rotation tool for a number of projections.

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33

Woodcock, C. L. "Practical Electron Tomography." Microscopy Today 4, no. 1 (February 1996): 30–38. http://dx.doi.org/10.1017/s155192950006702x.

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Despite the potential of the technique, electron tomography has yet to be widely used by biologists. This is in part related to the rather daunting list of equipment and expertise that are required. Thanks to continuing advances in theory and instrumentation, tomography is now more feasible for the non-specialist. One barrier that has essentially disappeared is the expense of computational resources. In view of this progress, it is time to give more attention to practical issues that need to be considered when embarking on a tomographic project. The following recommendations and comments are derived from experience gained during two long-term collaborative projects.

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34

Pattan, Anusha U., and Shubhangi D.C. "Optical Tomography: The Survey on Optical Tomographic Techniques." International Journal of Advanced Research in Computer Science and Software Engineering 7, no. 6 (June 30, 2017): 376–81. http://dx.doi.org/10.23956/ijarcsse/v7i6/0300.

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Arslan, Ilke, Toby Sanders, Peter Binev, Bruce C. Gates, and Alexander Katz. "New Discrete Tomographic Reconstruction Method for Electron Tomography." Microscopy and Microanalysis 21, S3 (August 2015): 2331–32. http://dx.doi.org/10.1017/s143192761501243x.

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36

Troyan, V. N., and G. A. Ryzhikov. "Diffraction tomography: Construction and interpretation of tomographic functionals." Journal of Mathematical Sciences 86, no. 3 (September 1997): 2773–86. http://dx.doi.org/10.1007/bf02355168.

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37

Aknoun, Sherazade, Benoit Wattellier, Pierre Bon, and Serge Monneret. "Tomographic Incoherent Phase Imaging, a Diffraction Tomography Alternative." Biophysical Journal 106, no. 2 (January 2014): 603a. http://dx.doi.org/10.1016/j.bpj.2013.11.3336.

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38

Zhai, Yuhu, and Steven A. Cummer. "Fast tomographic reconstruction strategy for diffuse optical tomography." Optics Express 17, no. 7 (March 19, 2009): 5285. http://dx.doi.org/10.1364/oe.17.005285.

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Kuś, Arkadiusz, Wojciech Krauze, and Małgorzata Kujawińska. "From digital holographic microscopy to optical coherence tomography – separate past and a common goal." Photonics Letters of Poland 13, no. 4 (December 30, 2021): 91. http://dx.doi.org/10.4302/plp.v13i4.1130.

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In this paper we briefly present the history and outlook on the development of two seemingly distant techniques which may be brought close together with a unified theoretical model described as common k-space theory. This theory also known as the Fourier diffraction theorem is much less common in optical coherence tomography than its traditional mathematical model, but it has been extensively studied in digital holography and, more importantly, optical diffraction tomography. As demonstrated with several examples, this link is one of the important factors for future development of both techniques. Full Text: PDF ReferencesN. Leith, J. Upatnieks, "Reconstructed Wavefronts and Communication Theory", J. Opt. Soc. Am. 52(10), 1123 (1962). CrossRef Y. Park, C. Depeursinge, G. Popescu, "Quantitative phase imaging in biomedicine", Nat. Photonics 12, 578 (2018). CrossRef D. Huang et al., "Optical Coherence Tomography", Science 254(5035), 1178 (1991). CrossRef D. P. Popescu, C. Flueraru, S. Chang, J. Disano, S. Sherif, M.G. Sowa, "Optical coherence tomography: fundamental principles, instrumental designs and biomedical applications", Biophys. Rev. 3(3), 155 (2011). CrossRef M. Wojtkowski, V. Srinivasan, J.G. Fujimoto, T. Ko, J.S. Schuman, A. Kowalczyk, J.S. Duker, "Three-dimensional Retinal Imaging with High-Speed Ultrahigh-Resolution Optical Coherence Tomography", Ophthalmology 112(10), 1734 (2005). CrossRef K.C. Zhou, R. Qian, A.-H. Dhalla, S. Farsiu, J.A. Izatt, "Unified k-space theory of optical coherence tomography", Adv. Opt. Photon. 13(2), 462 (2021). CrossRef A.F. Fercher, C.K. Hitzenberger, G. Kamp, S.Y. El-Zaiat, "Measurement of intraocular distances by backscattering spectral interferometry", Opt. Comm. 117(1-2), 43 (1995). CrossRef E. Wolf, "Determination of the Amplitude and the Phase of Scattered Fields by Holography", J. Opt. Soc. Am. 60(1), 18 (1970). CrossRef E. Wolf, "Three-dimensional structure determination of semi-transparent objects from holographic data", Opt. Comm. 1(4), 153 (1969). CrossRef V. Balasubramani et al., "Roadmap on Digital Holography-Based Quantitative Phase Imaging", J. Imaging 7(12), 252 (2021). CrossRef A. Kuś, W. Krauze, P.L. Makowski, M. Kujawińska, "Holographic tomography: hardware and software solutions for 3D quantitative biomedical imaging (Invited paper)", ETRI J. 41(1), 61 (2019). CrossRef A. Kuś, M. Dudek, M. Kujawińska, B. Kemper, A. Vollmer, "Tomographic phase microscopy of living three-dimensional cell cultures", J. Biomed. Opt. 19(4), 46009 (2014). CrossRef O. Haeberlé, K. Belkebir, H. Giovaninni, A. Sentenac, "Tomographic diffractive microscopy: basics, techniques and perspectives", J. Mod. Opt. 57(9), 686 (2010). CrossRef B. Simon et al., "Tomographic diffractive microscopy with isotropic resolution", Optica 4(4), 460 (2017). CrossRef B.A. Roberts, A.C. Kak, "Reflection Mode Diffraction Tomography", Ultrason. Imag. 7, 300 (1985). CrossRef M. Sarmis et al., "High resolution reflection tomographic diffractive microscopy", J. Mod. Opt. 57(9), 740 (2010). CrossRef L. Foucault et al., "Versatile transmission/reflection tomographic diffractive microscopy approach", J. Opt. Soc. Am. A 36(11), C18 (2019). CrossRef W. Krauze, P. Ossowski, M. Nowakowski, M. Szkulmowski, M. Kujawińska, "Enhanced QPI functionality by combining OCT and ODT methods", Proc. SPIE 11653, 116530B (2021). CrossRef E. Mudry, P.C. Chaumet, K. Belkebir, G. Maire, A. Sentenac, "Mirror-assisted tomographic diffractive microscopy with isotropic resolution", Opt. Lett. 35(11), 1857 (2010). CrossRef P. Hosseini, Y. Sung, Y. Choi, N. Lue, Z. Yaqoob, P. So, "Scanning color optical tomography (SCOT)", Opt. Expr. 23(15), 19752 (2015). CrossRef J. Jung, K. Kim, J. Yoon, Y. Park, "Hyperspectral optical diffraction tomography", Opt. Expr. 24(3), 1881 (2016). CrossRef T. Zhang et al., Biomed. "Multi-wavelength multi-angle reflection tomography", Opt. Expr. 26(20), 26093 (2018). CrossRef R.A. Leitgeb, "En face optical coherence tomography: a technology review [Invited]", Biomed. Opt. Expr. 10(5), 2177 (2019). CrossRef J.F. de Boer, R. Leitgeb, M. Wojtkowski, "Twenty-five years of optical coherence tomography: the paradigm shift in sensitivity and speed provided by Fourier domain OCT [Invited]", Biomed. Opt. Expr. 8(7), 3248 (2017). CrossRef T. Anna, V. Srivastava, C. Shakher, "Transmission Mode Full-Field Swept-Source Optical Coherence Tomography for Simultaneous Amplitude and Quantitative Phase Imaging of Transparent Objects", IEEE Photon. Technol. Lett. 23(11), 899 (2011). CrossRef M.T. Rinehart, V. Jaedicke, A. Wax, "Quantitative phase microscopy with off-axis optical coherence tomography", Opt. Lett. 39(7), 1996 (2014). CrossRef C. Photiou, C. Pitris, "Dual-angle optical coherence tomography for index of refraction estimation using rigid registration and cross-correlation", J. Biomed. Opt. 24(10), 1 (2019). CrossRef Y. Zhou, K.K.H. Chan, T. Lai, S. Tang, "Characterizing refractive index and thickness of biological tissues using combined multiphoton microscopy and optical coherence tomography", Biomed. Opt. Expr. 4(1), 38 (2013). CrossRef K.C. Zhou, R. Qian, S. Degan, S. Farsiu, J.A. Izatt, "Optical coherence refraction tomography", Nat. Photon. 13, 794 (2019). CrossRef

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40

Shang, E. C. "A new method of ocean acoustic tomographym—“Phase tomography.”." Journal of the Acoustical Society of America 83, S1 (May 1988): S102. http://dx.doi.org/10.1121/1.2025101.

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41

Carrion, Philip, Jesse Costa, Jose E. Ferrer Pinheiro, and Michael Schoenberg. "Cross‐borehole tomography in anisotropic media." GEOPHYSICS 57, no. 9 (September 1992): 1194–98. http://dx.doi.org/10.1190/1.1443333.

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Anisotropy has significant effect on traveltime cross‐borehole tomography. Even relatively weak anisotropy cannot be ignored if accurate velocity estimates are desired, since isotropic traveltime tomography treats anisotropy as inhomogeneity. Traveltime data in our examples were synthetically generated by a ray‐tracing code for anisotropic media, and the computed quasi‐P‐wave traveltimes were subsequently inverted using the “dual tomography” technique (Carrion, 1991). The results of the tomographic inversion show typical artifacts due to the anisotropy, and that accurate imaging is impossible without taking the anisotropy into account.

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42

Martone, M. E., S. Peltier, S. Lamont, A. Gupta, B. Ludaescher, S. Khetani, T. Molina, and M. H. Ellisman. "Increasing Access to Tomographic Resources: Web-based Telemicroscopy and Database." Microscopy and Microanalysis 7, S2 (August 2001): 92–93. http://dx.doi.org/10.1017/s1431927600026532.

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The application of electron tomography to cell biology has led to important insights into the 3D fine structure of subcellular processes and organelles. Tomography has been particularly useful for studying relatively large, multi-component structures such as the Golgi apparatus, mitochondria and synaptic complexes. When combined with very powerful high voltage electron microscopes, tomography has also provided high resolution quantitative views of extended structures such as neuronal dendrites in very thick sections (4 μm) at electron microscopic resolution. The utility of tomography is twofold: first, it provides 3D examination of subcellular structure without the need for serial section analysis; second, because the computed slices through the tomographic volumes can be much thinner than is possible to produce by physical sectioning, it reveals structural detail in the range of 5-30 nm that tends to be obscured in conventional thin sections. Tomographic analysis has forced re-assessment of long-standing views of organelles such as mitochondria and the Golgi apparatus and as the technique advances, additional insights are likely forthcoming.Electron tomography is an expensive technique, both in terms of the instruments used and the computational resources required. The three major high voltage electron microscope resources in the United States, San Diego, Boulder and Albany, all are actively engaged in tomographic research and offer this important technology to the scientific community at large.

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43

REZAEE, M., M. A. JAFARIZADEH, and M. MIRZAEE. "GROUP THEORETICAL APPROACH TO QUANTUM ENTANGLEMENT AND TOMOGRAPHY WITH WAVELET TRANSFORM IN BANACH SPACES." International Journal of Quantum Information 05, no. 03 (June 2007): 367–86. http://dx.doi.org/10.1142/s0219749907002967.

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The intimate connection between the Banach space wavelet reconstruction method for each unitary representation of a given group and some of well-known quantum tomographies, such as tomography of rotation group, spinor tomography and tomography of unitary group, is established. Also both the atomic decomposition and Banach frame nature of these quantum tomographic examples are revealed in detail. Finally, we consider separability criteria for any state with group theoretical wavelet transform on Banach spaces.

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44

Vermelho, Marli Batista Fernandes, Ademir Silva Correia, Tânia Cibele de Almeida Michailowsky, Elizete Kazumi Kuniyoshi Suzart, Aline Santos Ibanês, Lanamar Aparecida Almeida, Zarifa Khoury, and Mário Flores Barba. "Abdominal alterations in disseminated paracoccidioidomycosis: computed tomography findings." Radiologia Brasileira 48, no. 2 (April 2015): 81–85. http://dx.doi.org/10.1590/0100-3984.2013.0025.

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Objective:To evaluate the incidence and spectrum of abdominal computed tomography imaging findings in patients with paracoccidioidomycosis.Materials and Methods:Retrospective analysis of abdominal computed tomography images of 26 patients with disseminated paracoccidioidomycosis.Results:Abnormal abdominal tomographic findings were observed in 18 patients (69.2%), while no significant finding was observed in the other 8 (30.8%) patients.Conclusion:Computed tomography has demonstrated to play a relevant role in the screening and detection of abdominal abnormalities in patients with disseminated paracoccidioidomycosis.

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45

Woodcock, C. L. "Practical electron tomography." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 742–43. http://dx.doi.org/10.1017/s0424820100140087.

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Despite the potential of the technique, electron tomography has yet to be widely used by biologists. This is in part related to the rather daunting list of equipment and expertise that are required. Thanks to continuing advances in theory and instrumentation, tomography is now more feasible for the non-specialist. One barrier that has essentially disappeared is the expense of computational resources. In view of this progress, it is time to give more attention to practical issues that need to be considered when embarking on a tomographic project. The following recommendations and comments are derived from experience gained during two long-term collaborative projects.Tomographic reconstruction results in a three dimensional description of an individual EM specimen, most commonly a section, and is therefore applicable to problems in which ultrastructural details within the thickness of the specimen are obscured in single micrographs. Information that can be recovered using tomography includes the 3D shape of particles, and the arrangement and dispostion of overlapping fibrous and membranous structures.

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46

Kassebaum, Denise K., and John D. McDowell. "TOMOGRAPHY." Dental Clinics of North America 37, no. 4 (October 1993): 567–74. http://dx.doi.org/10.1016/s0011-8532(22)00242-7.

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47

Phillips, Emilia. "Tomography." Cream City Review 37, no. 2 (2013): 31–32. http://dx.doi.org/10.1353/ccr.2013.0065.

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48

Munshi, Prabhat. "Tomography." Resonance 12, no. 11 (November 2007): 54–62. http://dx.doi.org/10.1007/s12045-007-0114-2.

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49

Tsai, Victor C., Christian Huber, and Colleen A. Dalton. "Towards the geological parametrization of seismic tomography." Geophysical Journal International 234, no. 2 (March 24, 2023): 1447–62. http://dx.doi.org/10.1093/gji/ggad140.

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SUMMARY Seismic tomography is a cornerstone of geophysics and has led to a number of important discoveries about the interior of the Earth. However, seismic tomography remains plagued by the large number of unknown parameters in most tomographic applications. This leads to the inverse problem being underdetermined and requiring significant non-geologically motivated smoothing in order to achieve unique answers. Although this solution is acceptable when using tomography as an explorative tool in discovery mode, it presents a significant problem to use of tomography in distinguishing between acceptable geological models or in estimating geologically relevant parameters since typically none of the geological models considered are fit by the tomographic results, even when uncertainties are accounted for. To address this challenge, when seismic tomography is to be used for geological model selection or parameter estimation purposes, we advocate that the tomography can be explicitly parametrized in terms of the geological models being tested instead of using more mathematically convenient formulations like voxels, splines or spherical harmonics. Our proposition has a number of technical difficulties associated with it, with some of the most important ones being the move from a linear to a non-linear inverse problem, the need to choose a geological parametrization that fits each specific problem and is commensurate with the expected data quality and structure, and the need to use a supporting framework to identify which model is preferred by the tomographic data. In this contribution, we introduce geological parametrization of tomography with a few simple synthetic examples applied to imaging sedimentary basins and subduction zones, and one real-world example of inferring basin and crustal properties across the continental United States. We explain the challenges in moving towards more realistic examples, and discuss the main technical difficulties and how they may be overcome. Although it may take a number of years for the scientific program suggested here to reach maturity, it is necessary to take steps in this direction if seismic tomography is to develop from a tool for discovering plausible structures to one in which distinct scientific inferences can be made regarding the presence or absence of structures and their physical characteristics.

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Wang, G., and H. Yu. "Can interior tomography outperform lambda tomography?" Proceedings of the National Academy of Sciences 107, no. 22 (May 12, 2010): E92—E93. http://dx.doi.org/10.1073/pnas.1002473107.

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