Tomographic Profile Research Articles

Soft glass optical fiber characterization with X-ray computed microtomography

The high loss due to the presence of strong phonon resonances makes silica fibers unfit for applications in the mid-infrared spectral range. This has led to the development of specialty optical fibers, based on novel materials and manufacturing techniques. In some cases, the characterization of these new fibers by means of standard techniques may be challenging. Fiber manufacturers would strongly benefit from a tool, which is capable of checking the geometrical and optical properties of fibers (either after fiber drawing, or even in real-time, during the drawing process). Here, we propose and demonstrate that absorption contrast X-ray computed microtomography is a non-destructive technique, capable of characterizing both geometrical and optical properties of specialty optical fibers. We experimentally verified that the tomographic intensity profile in the fiber core has the same shape as the refractive index profile, which we determined via energy-dispersed X-ray spectroscopy. We tested step- and graded-index soft glass fibers, both purchased and made in-house. Owing to the presence of high atomic number elements, which provide higher X-ray cross-section, soft glasses were more suitable than silica for their characterization via X-ray computed microtomography.

Self-Sustained Constant Anodic Dissolution Rate on Iron Electrode Under a Magnetic Field

The evolution of the wavy surface of an iron electrode with anodic polarization time in a sulfuric acid solution under a 0.4 T magnetic field is quantified by 3D tomographic depth profile measurements. The electrode surface after anodic dissolution under a magnetic field is irregular and the 3D profile changes with the anodic polarization time. The anodic dissolution rate is specific to the geometrical location on the electrode, which is, in general, insensitive to the polarization time as well as the surface irregularity.

Assessment of underlying topography and forest height inversion based on TomoSAR methods

ABSTRACT Due to the strong penetrability, long-wavelength synthetic aperture radar (SAR) can provide an opportunity to reconstruct the three-dimensional structure of the penetrable media. SAR tomography (TomoSAR) technology can resynthesize aperture perpendicular to the slant-range direction and then obtain the tomographic profile consisting of power distribution of different heights, providing a powerful technical tool for reconstructing the three-dimensional structure of the penetrable ground objects. As an emerging technology, it is different from the traditional interferometric SAR (InSAR) technology and has advantages in reconstructing the three-dimensional structure of the illuminated media. Over the past two decades, many TomoSAR methods have been proposed to improve the vertical resolution, aiming to distinguish the locations of different scatters in the unit pixel. In order to cope with the forest mission of European Space Agency (ESA) that is designed to provide P-band SAR measurements to determine the amount of biomass and carbon stored in forests, it is necessary to systematically evaluate the performance of forest height and underlying topography inversion using TomoSAR technology. In this paper, we adopt three typical algorithms, namely, Capon, Multiple Signal Classification (MUSIC), and Compressed Sensing (CS), to evaluate the performance in forest height and underlying topography inversion. The P-band airborne full-polarization (FP) SAR data of Lopè National Park in the AfriSAR campaign implemented by ESA in 2016 is adopted to verify the experiment. Furthermore, we explore the effects of different baseline designs and filter methods on the reconstruction of the tomographic profile. The results show that a better tomographic profile can be obtained by using Hamming window filter and Capon algorithm in uniform baseline distribution and a certain number of acquisitions. Compared with LiDAR results, the root-mean-square error (RMSE) of forest height and underlying topography obtained by Capon algorithm is 2.17 m and 1.58 m, which performs the best among the three algorithms.

Clinical and Brain Computed Tomographic Profile of Stroke Patients in a Tertiary Hospital, North Central Nigeria

Background: Stroke is a common neurological disorder associated with high morbidity and mortality worldwide. Aim: The study set out to characterize the clinico-radiologic pattern of stroke patients as well as to determine the correlation between the clinical and computed tomographic (CT) scan findings in a tertiary hospital in Makurdi, North central Nigeria. Method: This was a retrospective study of 145 patients with clinically suspected stroke, who underwent CT imaging at the Benue State University Teaching Hospital, Makurdi Nigeria between December 2020 and June 2022. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 26. Results: Of the 145 clinically diagnosed cases of stroke, 122 (84.1%) were confirmed on CT. 7 (4.8%) were stroke mimics and 16 (11.0%) were normal. There were 65 (53.3%) males and 57 (46.7%) females with a male: female ratio of 1.1:1. The mean age at presentation was 58.7 ± 12.87 years with age range of 69 - 78 years being affected most. Few cases of stroke were seen below the age of fifty years. Ischaemic stroke was the commonest 77 (63.1%) followed by primary intracerebral haemorrhage (ICH) 38 (31.4%) then sub arachnoid haemorrhage (SAH) 5 (4.1%). Most infarcts were below 10 cm2, while for ICH volume those below 10 cm3 and above 100 cm3 occurred in equal proportion. Hypertension was the main risk factor for stroke with respective frequency of 31 (21.4%) and 94 (64.8%) in isolation or associated with other risk factors like Diabetes mellitus (DM), hyperlipidemia, alcohol, and smoking among others. There was significant correlation between clinical and radiological diagnosis of stroke (p Conclusion: The result showed slight male preponderance with majority of suspected stroke confirmed by CT; these were mostly of ischaemic type. There was significant correlation between clinical and radiologic diagnosis of stroke while hypertension was the main risk factor identified.

Profil des trous maculaires à Cotonou

To establish the epidemiological and tomographic profile of macular holes in the Beninese subject. This cross-sectional study included consecutive patients seen for macular testing during the period from January 2016 to August 2017 at the St. Anthony of Padua Retinal Testing Center in Cotonou (Benin). All patients who had a macular hole and macular OCT were included. To define macular hole types, we used the 2013 DUKER New Classification and analyzed for each case: age sex, history, involved eye, fellow eye, visual acuity, hole type, hole diameter, status of the vitreous cortex, edge edema, mean macular thickness, presence of vitreomacular traction, epimacular membrane, and retrofoveal choroidal thickness. Patients with a pseudo-macular hole or lamellar hole were excluded. During this study period, 401 patients underwent a macular OCT procedure at the Retinal Testing Center, with 22 patients having a macular hole, of which 15 women and 07 men for a sex ratio of 2.14 women to men. The mean age of the patients was 61±10 years, with a median age of 63 years. The mean diameter of the holes was 705μm±232μm. No small holes were found. The mean central macular thickness was 272μm±39μm. In 52.4% of cases, the condition of the felloweye indicated the presence of vitreomacular traction. The etiological profile of the macular hole found in 72.7% a primary origin, and a secondary origin (diabetic and traumatic) in 13.6% and 9.09% respectively. The majority of the macular holes observed were large macular holes, which could be explained by the progressive course of these macular holes as well as late detection. Over half of the fellow eyes showed vitreomacular traction, reflecting the potential risk of bilateralization. Macular hole is a pathology of the vitreomacular interface, tending to be large in our geographic context. On OCT, the data found remain comparable those reported in the literature.

UAVSAR Tomography for Vertical Profile Generation of Tropical Forest of Mondah National Park, Gabon

AbstractPolarimetric synthetic‐aperture radar (SAR) remote sensing has been widely used for structural and biophysical parameters retrieval of forest vegetation. It has been found that the combination of polarimetric properties and interferometric characteristics of SAR remote sensing provides the capacity to retrieve forest height. The prime objective of this research was to investigate the potential of Polarimetric Synthetic Aperture Radar Tomography (PolTomSAR) for the forested and river region of Mondah National Park, Gabon. SAR tomography is an improved method for acquiring the height of geographical features. UAVSAR L‐band fully polarimetric multibaseline data have been used in this research (1.275 GHz). SAR data and ground data over the area have been collected in the year 2016. With the superresolution‐based Capon algorithm, multiple scatterers located at a different vertical position in the same azimuth range cell has been resolved and reconstructed. This work provides a framework for Capon‐based tomographic processing of multibaseline UAVSAR data for vertical profile retrieval of forest vegetation. The height profile of the forest patch having sparse, as well as dense vegetation, were retrieved. The vertical profile for a single azimuthal bin was obtained in range direction. The tomographic profile obtained was cross‐checked with the field‐measured forest height for the 16 locations in Mondah National Park, Gabon. To check the accuracy of the applied method, the statistical method of R2 and root‐mean‐square error (RMSE) is employed. The obtained RMSE of the result is 4.21 m and R2 is 0.92. The obtained results were concluded to find the potential of the Capon algorithm for the tomographic reconstruction of UAVSAR data.

The use of L‐PRF and A‐PRF for three‐dimensional gain in implantation sites – The open wound technique

Background Since the discovery of osseointegration in the 1960s, the greatest challenge for the placement of functional implants is the presence of an implantation site - a muco-osseous envelope that guarantees these proper three-dimensional positioning. Several strategies to overcome this quest have been proposed in the last decades, most notably techniques of Tissue Engineering (Langer and Vacanti, 1993). In recent years dentists have seen a primordial shift in regenerative and reconstructive techniques such as the inductive and conductive function of potential of blood concentrates. Through the fundamental use of Tissue Engineering in clinical procedures, technical and conceptual modifications have contributed to the adoption of more scientifically efficient, less-invasive and less-morbid solutions. These have substantially improved the outcomes of surgical procedures with the use of three-dimensional blood transitory matrix. Nonetheless, achieving clinical results would require a revolution in current surgical techniques. Obtaining of maximum efficiency when using blood concentrate matrices can be conquered through principals of biomodulation with biofunctional sutures and biotensegrity. In this scenario, the aim of this work is to present and describe of procedures that we call Biologically Intelligent Tissue Engineering (BITE), through a series of clinical cases using a new procedure called the Open Wound Technique. Aim/Hypothesis The aim of this work is to evaluate the gain of keratinized mucosa+ phenotype modification+ bone profile in twenty implantation sites. This will be performed with the use of BITE (Biologically Intelligent Tissue Engineering) methodology, using the technique of the Open Wound. Material and Methods Twenty edentulous sites of immediate and late placement of implants were evaluated by calibrate examination in a probe measuring the thickness of peri-implant mucosa. After the implant's placement, the surgical site was filled with L-PRF or A-PRF plugs and covered by six to eight PRF membranes inserted in bone-mucoperiosteal flap interface. These were left exposed to the oral environment. The flaps were stabilized by layered sutures. The evolution of the wound repair was registered periodically (3 days, 7 days, 15 days, 30 days and 1-year follow-up), as well as the thickness of keratinized mucosa and tomographic profile were measured within 30 and 60 days and after 1 year. Results In all cases the PRF plugs and membranes were replaced by healthy keratinized tissue with 1.5–4 mm thickness (average of 3 mm) and modified with peri-implant phenotype. The bone profile average gain was identified by tomographic evaluation and ranged in thickness from 0.5 to 1.5 mm. The value remained the same after 1 year of follow-up. Conclusion and Clinical Implications The Biologically Intelligent Tissue Engineering (BITE), can and will improve the peri-implant tissues with three-dimensional gain through a series of a new procedure called the Open Wound Technique. The outcome will be a less morbid and invasive strategy for development and correction of small defects in implantation sites

Forest Above-Ground Biomass Estimation Using Single-Baseline Polarization Coherence Tomography with P-Band PolInSAR Data

Forest above ground biomass (AGB) extraction using Synthetic Aperture Radar (SAR) images has been widely used in global carbon cycle research. Classical AGB inversion methods using SAR images are mainly based on backscattering coefficients. The polarization coherence tomography (PCT) technology which can generate vertical profiles of forest relative reflectivity, has the potential to improve the accuracy of biomass inversion. The relationship between vertical profiles and forest AGB is modeled by some parameters defined based on geometric characteristics of the relative reflectivity distribution curve. But these parameters are defined without physical characteristics. Among these parameters, tomographic height (TomoH) is considered as the most important one. However, TomoH only corresponds to the highest volume relative reflectivity, which is lower than the actual forest height, affecting the accuracy of forest height and AGB inversion. In this paper, we introduce a new parameter, the canopy height (Hac), for AGB inversion by analyzing the vertical backscatter power loss. Then, we construct an inversion model based on the combination of the new parameter (Hac) and other parameters from the tomographic profile. The P-band polarimetric SAR datasets of the European Space Agency (ESA) BioSAR 2008 campaign acquired over Krycklan Catchment are selected for the verification experiment at two different flight directions. The results show that Hac performs better in estimating forest height and AGB than TomoH does. The inversion root mean square error (RMSE) of the proposed method is 18.325 t ha−1, and the result of using TomoH is 21.126 t ha−1.

Fast and Reliable Measurement of Thin Film Thickness Profile Based on Wavelet Transform in Spectrally Resolved White-Light Interferometry

We describe an improved version of spectrally resolved white-light interferometry that enables us to measure thin film thickness profile in a faster and more reliable way. Both the interferometric phase and the spectral reflectance of thin films are monitored at the same time in order to obtain accurate thickness and top surface height of thin films, leading to the complete reconstruction of the 3D tomographic profile of thin films. To do that, information related to the layers of thin films and top surface height of thin films must be decoupled and, based on wavelet transform, allowing it to be achieved without introducing two troublesome measurement steps or spectral carrier frequency. The experimental results for a prepared specimen showed that thin film thickness profile could be determined within an error range of 9 nm compared to well-known techniques. Due to the rigorous approach used in the proposed method, it is well suited for the in-line high-speed inspection of microelectronic devices produced in large quantities as is done in the semiconductor and flat-panel display industries.

Comparison of methods for the reduction of reconstructed layers in atmospheric tomography.

For the new generation of extremely large telescopes (ELTs), the computational effort for adaptive optics (AO) systems is demanding even for fast reconstruction algorithms. In wide-field AO, atmospheric tomography, i.e., the reconstruction of turbulent atmospheric layers from wavefront sensor data in several directions of view, is the crucial step for an overall reconstruction. Along with the number of deformable mirrors, wavefront sensors and their resolution, as well as the guide star separation, the number of reconstruction layers contributes significantly to the numerical effort. To reduce the computational cost, a sparse reconstruction profile which still yields good reconstruction quality is needed. In this paper, we analyze existing methods and present new approaches to determine optimal layer heights and turbulence weights for the tomographic reconstruction. Two classes of methods are discussed. On the one hand, we have compression methods that downsample a given input profile to fewer layers. Among other methods, a new compression method based on discrete optimization of collecting atmospheric layers to subgroups and the compression by means of conserving turbulence moments is presented. On the other hand, we take a look at a joint optimization of tomographic reconstruction and reconstruction profile during atmospheric tomography, which is independent of any a priori information on the underlying input profile. We analyze and study the qualitative performance of these methods for different input profiles and varying fields of view in an ELT-sized multi-object AO setting on the European Southern Observatory end-to-end simulation tool OCTOPUS.

Spaceborne PolInSAR tomography for vertical profile retrieval of forest vegetation

Forest height plays a crucial role in investigating the biophysical parameters of forests and the terrestrial carbon. PolInSAR-based inversion modeling has been successfully implemented on airborne and spaceborne synthetic aperture radar (SAR) data. SAR tomography is a recent approach to separate scatterers in the cross-range direction and generate its vertical profile. This study highlights the potential of tomographic processing of multibaseline fully polarimetric Radarsat-2 C-band SAR data to estimate radar reflectivity at different forest height levels. A teak patch of Haldwani forest in Uttarakhand state of India was chosen as the test site to perform tomography. Since SAR tomography is a spectral estimation problem, Fourier transform (FT), beamforming (BF), and Capon-based spectral estimators were applied on the dataset to obtain the backscattering power contributions at different forest height levels. Fourier showed high backscatter power retrieval at different forest heights. The radar reflectivities at different heights were significantly reduced by BF followed by Capon. Tomographic profile of FT severely suffered from high sidelobes, which was drastically reduced by implementing BF. Capon further reduced the sidelobes and achieved a substantially improved tomographic profile. The height maps were generated for these algorithms and validated with ground truth data.

SU‐C‐209‐07: Phantoms for Digital Breast Tomosynthesis Imaging System Evaluation

Purpose:Digital Breast Tomosynthesis (DBT) is gaining importance in breast imaging. There is a need for phantoms that can be used for image evaluation and comparison. Existing commercially available phantoms for DBT are expensive and may lack clinically relevant test objects. The purpose of this study is to develop phantoms for DBT evaluation.MethodsFour phantoms have been designed and constructed to assess the image quality (IQ) of two DBT systems. The first contains a spiral of 0.3 mm SiC beads in gelatin to measure the tomographic slice thickness profile and uniformity of coverage in a series of tomographic planes. The second contains simulated tumors inclined with respect to the phantom base to assess tomographic image quality. The third has a tilted array of discs with varying contrast and diameter. This phantom was imaged alone and in a stack of TE slabs giving 2 to 10 cm thickness. The fourth has a dual wedge of glandular and adipose simulating materials. One wedge contains discs with varying diameter and thickness; the other supports a mass with six simulated spicules of varying size and a cluster of simulated calcifications. The simulated glandular tissue material varies between 35 and 100% of the total thickness (5.5 cm).Results:All phantoms were scanned successfully. The best IQ comparison was achieved with the dual wedge phantom as demonstrated by the spiculated mass and calcifications. Images were evaluated by two radiologists and one physicist. The projection images and corresponding set of tomographic planes were comparable and the synthesized projection images were inferior to the projection images for both systems.Conclusion:Four phantoms were designed, constructed and imaged on two DBT systems. They successfully demonstrated performance differences between two systems, and between true and synthesized projection images. Future work will incorporate these designs into a single phantom.

Computerised tomographic profile of ethmoid roof on basis of keros classification among ethnic Kashmiri’s

<p class="abstract"><strong><span lang="EN-US">Background: </span></strong>The purpose of this study was to evaluate the ethmoid roof on computerized tomography of nose and paranasal sinuses of Kashmiri people and distribute them on basis of KEROS classification.</p><p class="abstract"><strong><span lang="EN-US">Methods: </span></strong>Cross sectional descriptive study, the randomly selected paranasal sinus computed tomography (PNS CT) scans coronal cuts .Total of One hundred PNS CT scans done at the SMHS Hospital from April 2015 to September 2015 were reviewed, and selected for study. The bilateral heights of the lateral lamellae of the cribriform plate were obtained, independently coded, and classified according to keros.</p><p class="abstract"><strong><span lang="EN-US">Results: </span></strong>The mean height of the lateral lamella among Kashmir’s was seen to be 5.08mm and 29% of patient’s CT PNS were classified as Keros I, 61% were classified as Keros II and 10% were classified as Keros III. There was significant difference in the distribution of Keros classification between the right and left lateral lamella. There was no significant difference in the height of the lateral lamella (t-test: p=0.98 on right side & p =0.89 on left side) and the distribution of Keros classification (Fisher’s Exact test: p = 0.823) among younger (1-14 year) and older (>14 year) Kashmiri age groups. There is significant difference in the height (t-test: p=0.03 on right side and p=0.03 on left side) and the distribution of Keros classification is statistically insignificant (Fishers Exact Test: p=0.11) between Kashmiri females and males.</p><p class="abstract"><strong><span lang="EN-US">Conclusions: </span></strong>Preoperative assessment of ethmoid roof anatomy and keros level is mandatory for alerting the surgeon of the potential iatrogenic injury during endoscopic sinus surgeries to minimize the grave complications during ESS.</p>

Forest aboveground biomass estimation using polarization coherence tomography and PolSAR segmentation

Forest aboveground biomass (AGB) is essential for monitoring the carbon cycle budget and climate change. This study proposes a method for the estimation of forest AGB based on polarization coherence tomography (PCT) and polarimetric synthetic aperture radar (PolSAR) segmentation. The data used are the single-baseline polarimetric SAR interferometry data acquired by the German Aerospace Center’s E-SAR sensor at the L-band over the city of Traunstein and its vicinity in 2003. First, vertical structure tomographic profiles (relative reflectivity distribution in vertical direction) were produced by PCT for each pixel and then averaged within each field-surveyed forest stand to obtain the mean tomographic profile. Next, the mean vertical tomographic profiles were parameterized by 10 shape parameters. Several models for biomass estimation were designed based on the relationships between the definition parameters and the in situ measurements using backward step-wise regression and the M-fold (10-fold) cross-validation method. The best model was chosen by evaluation criteria such as R, root mean square error (RMSE), R2, etc. Forest polygons (objects) were produced by image segmentation using forest heights, (produced by coherence optimization representing double-bounce scattering mechanism), (produced by coherence optimization representing the volume scattering mechanism), and the volume scattering mechanism class (produced by Freeman–Durden decomposition and Whishart classification). Finally, the selected model was used to estimate the AGB of each forest polygon and was validated using ground-measured biomass with R2 of 0.883 and RMSE of 39.98 tons ha−1. The results show that the proposed method works well for the estimation of forest AGB. No saturation phenomena have been observed even for the forest stands with AGB larger than 500 tons ha−1.

Development of gamma-ray diagnostics for ITER

Gamma-ray spectrometry is a diagnostic tool for fast ions in large tokamak plasmas. The information provided allows us to identify and simultaneously distinguish the presence of fast α-particles and other ions (H, D, T, 3He) to obtain information on their energy distribution and relative densities, in addition to performing a tomographic radial profile reconstruction of the γ-emission sources. The lack of vertical diagnostic ports in ITER makes the implementation of tomographic neutron and γ-ray systems more complicated. The use of a vertical divertor port for the implementation of a vertical viewpoint is currently suggested. The strong magnetic field (∼2 T) found there makes it hard to use conventional multi-dynode photomultipliers as light detectors. Instead, the use of micro-channel plate photomultipliers is suggested here. Investigations of the magnetic field impact on the performance of the γ-spectrometer with a micro-channel photomultiplier are carried out. A high-speed pulse height analysis technique, which allows us to trace gain changes in the photomultiplier tube, is developed at the Ioffe Institute. The tests demonstrate the feasibility of γ-spectrometric measurements in the divertor port provided that micro-channel photomultiplier detectors and the developed high-speed technique are used.

Gamma-Ray Spectrometry of Hot Plasmas

Gamma-ray spectrometry provides diagnostics of fast ion behavior in plasmas of large tokamaks. Information acquiring with the gamma-ray diagnostics gives possibility to identify and distinguish simultaneously presence of fast alpha-particles and other ions (H, D, T, 3He), to obtain its relative densities and also to perform tomographic radial profile reconstruction of the gamma-emission sources.

Ionospheric measurement with GPS: Receiver techniques and methods

Accurate characterization of ionospheric parameters such as total electron content (TEC) and scintillation (signal fluctuation due to ionospheric irregularities) is critical to all users of GPS, whether the ultimate goal is measurement in navigation, geodesy, ionospheric, or atmospheric studies. Improved absolute TEC measurement accuracy is demanded by many global ionospheric characterization schemes, where small errors can be magnified in 3‐D tomographic profile reconstructions. We present research showing that there are three errors, or biases that typically result from characterizing TEC with GPS receiver data. These biases are (1) estimation, instead of measurement of receiver differential code bias (DCB); (2) ionospheric divergence of pseudorange‐code‐derived TEC resulting from code smoothing; and (3) delay of pseudorange TEC as a result of code smoothing. We present results of ionospheric data collected with a receiver that mitigates these biases to demonstrate the utility of improved accuracy, particularly for ingestion into tomographic reconstructions, but also for conversion from slant to vertical TEC.

Pneumonia eosinofílica crônica secundária ao uso prolongado de nitrofurantoína: achados da tomografia computadorizada de alta resolução do tórax

The authors report the case of a female patient who developed chronic eosinophilic pneumonia secondary to long-term use of nitrofurantoin for prophylaxis of recurrent urinary tract infections due to urethral stenosis. On high-resolution computed tomography scans, the pulmonary reaction to nitrofurantoin most commonly manifests as an interstitial-alveolar pattern in both lung bases. However, in this case, the alterations were most pronounced in the periphery of the upper lobes. In itself, this tomographic profile is strongly indicative of chronic eosinophilic pneumonia. The patient had previously been submitted to an open lung biopsy. The diagnosis of chronic eosinophilic pneumonia was confirmed through a review of the biopsy.

Velocity and Mass Flow Rate Profiles of Particle Conveying Using Electrical Charge Tomography

This paper describes measurements made on a gravity drop conveyor using two arrays of axially spaced electrodynamic sensors to measure axial velocities close to the wall of the conveyor and velocity profiles of both flowing sand and plastic beads. The level of correlation obtained using pixels is investigated. The velocity profile is combined with a tomographic concentration profile to estimate the mass flow profile, which is summed over the measurement cross-section to estimate the mass flow rate. A calibration of tomographically determined mass flow rate versus actual mass flow rate is presented.

Velocity and mass flow rate profiles of dry powders in a gravity drop conveyor using an electrodynamic tomography system

This paper describes measurements made on a gravity drop conveyor using two arrays of axially spaced electrodynamic sensors to measure axial velocities close to the wall of the conveyor and velocity profiles both of flowing sand and of plastic beads. The level of correlation obtained using pixels is investigated. The velocity profile is combined with a tomographic concentration profile to estimate the mass flow profile, which is summed over the measurement cross section to estimate the mass flow rate. A calibration of the tomographically determined mass flow rate versus the actual mass flow rate is presented.